Tag: heart rate variability

Threshold Versus VO2max Training: Are We Asking the Right Question?

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Kate Oldham racing the 10 k freestyle at the Trondheim World Cup in December 2025. Races of 5 to 15 kilometers, Jim Galanes points out, are not raced at threshold. (Photo: Modica/NordicFocus)

For the last couple of decades, the priority for high-intensity training has shifted from threshold, to VO2max, and now back to threshold again. Nowadays threshold training is increasingly presented as the ideal endurance training intensity. The suggestion is a high aerobic stimulus at a low recovery cost, repeatable and sustainable. VO2max is often portrayed as the opposite: a very high stimulus, high stress, very high fatigue, and something to be used carefully, if at all. Folks, we have seen this story before, in the threshold boom of the mid to late ’90s.

From some perspectives this may be intuitively correct and perhaps logical. If we compare one minute of threshold work to one minute at VO2max intensity, the VO2max work is more demanding. That is a no-brainer. There is more carbohydrate use, higher oxygen demand, higher lactate production, greater perceived exertion and generally a greater physiological disturbance. But is that the way training really works? We build training plans around individual workouts and daily and weekly loads, not per minute of high-intensity training.

For example, we might plan 5 x 4 minutes at VO2max intensity, or 20 minutes of total work. Or it might be 4 x 10 minutes at threshold, or 40 minutes of total work. When we look at the load of the whole session, things become far less clear. Both types of training produce similar adaptations, although the adaptive signal from the higher-intensity work is much stronger, and there is little evidence that a threshold session creates less recovery demand than an appropriately controlled VO2max session.

This is really the point I want to make. We need to stop confusing intensity with training load, and, perhaps more important, we need to stop confusing training load with the recovery timeline. They are related, but they are not the same thing.

As I have written before, threshold is a moving target, and defining it is problematic. There are perhaps a dozen or more methods used to determine threshold, and they can produce very different speeds, heart rates, power outputs and lactate values. Some athletes are working just above LT1 and calling it threshold. Others are working around 4 mmol, and others are using ventilatory threshold, critical power, some percentage of race pace, or simply an intensity that feels controlled and hard. So when people say “threshold training,” I am not sure we are even talking about the same thing. That alone should make us careful about assigning a fixed physiological cost or benefit to threshold training.

The generally accepted training model is usually described like this: easy endurance training provides a relatively small stimulus at a relatively low cost, so we need a lot of it. Threshold gives us a much larger aerobic stimulus, still at a manageable recovery cost. VO2max gives us a very large stimulus, but at a very high recovery cost. Again, that makes intuitive sense, but is it true when we compare realistic sessions? I am not convinced it is. In fact, I am certain it is not.

If we think of training load in simple terms, it is a combination of intensity and duration. Higher intensity produces greater load per minute, while longer duration produces more total load. A 3-hour easy workout, for example, produces a bigger training load than a 75-minute workout with 5 x 4 minutes of VO2max intervals. This is obvious, but somehow we often forget it when discussing threshold and VO2max training.

Take a typical VO2max workout of five by four minutes, 20 minutes of work. Using Firstbeat’s TRIMP model, that might create about 55 to 60 TRIMP. Now take a threshold workout of four by ten minutes, 40 minutes of work. That might generate something in the 95 to 100 TRIMP range. With Firstbeat we can also look at EPOC as an estimate of the disturbance of homeostasis. Again, these are estimates and certainly not perfect measures, but 20 minutes at around 90 percent of VO2max might produce an EPOC of around 175 ml/kg, while 40 minutes at around 85 percent might produce an EPOC of 225 ml/kg. Once again the threshold workout produces a significantly higher stress load.

I don’t want to get hung up on whether those exact Firstbeat numbers are accurate, because that is not really the point. The point is that it is entirely possible for the lower-intensity session to produce the larger total load, and that should not surprise anyone, because it is twice as long.

The same thing happens if we use session RPE. Twenty minutes of VO2max work at an RPE of 9 gives us 180 AU (arbitrary units), while forty minutes of threshold at an RPE of 6 gives us 240 AU. Again, the threshold session creates the larger estimated training load. That does not prove threshold is more stressful or that it takes longer to recover from. TRIMP and session RPE are measures or estimates of training load, not measurements of recovery time.

We have at least three different things being discussed as if they were the same: the intensity of the exercise, the total load of the workout, and how long it takes the athlete to recover. A VO2max interval clearly creates greater physiological disturbance per minute. A longer threshold session may create a greater total training load. Neither one, by itself, tells us which athlete will be better recovered 24 or 48 hours later.

High cost per minute is not the same thing as high cost per session, and high session load is not necessarily the same thing as longer recovery.

Otto Invenius, Campbell Wright, Maxime Germain and Adam Runnalls climbing the Stelvio Pass on rollerskis above Livigno, Italy, in July 2025. The adaptations from threshold and VO2max work overlap far more than the zone names suggest. (Photo: Manzoni/NordicFocus)

What Are We Actually Trying to Adapt?

The other issue is that we spend far too much time talking about training zones and not enough time talking about desired adaptations. What adaptations are we trying to create? That should come first.

VO2max training provides a very strong aerobic stimulus at near-maximal oxidative capacity. It can increase maximal cardiac output, improve oxygen transport, create very high muscular oxygen demand and expose the athlete to speeds and power outputs similar to race demands. Threshold training lets us accumulate a large amount of work at a high aerobic fractional utilization. It can improve sustainable speed or power, oxidative capacity at that intensity, and the ability to maintain a high percentage of maximal aerobic power for a longer period of time.

These adaptations overlap a great deal. I sometimes hear people talk as if threshold develops lactate clearance and the muscles’ ability to sustain work, while VO2max develops the central cardiovascular system. But VO2max training creates a large muscular stimulus as well. ATP turnover is very high, calcium flux is high, metabolic disturbance is high, and the signaling associated with mitochondrial biogenesis is substantial. VO2max training is not simply “central cardiovascular training.” It also provides a significant peripheral training stimulus.

Threshold training obviously produces a similar but slightly smaller mitochondrial and muscular signal for adaptation. But I think its real advantage may be something much simpler. Because the intensity is lower, we can normally do considerably more of it. That allows us to accumulate a large amount of work at a high aerobic fractional utilization, with substantial muscular recruitment and a large amount of sport-specific work.

That may be threshold training’s most important characteristic. Not that it creates some unique physiological adaptation unavailable at other intensities, but that it allows us to accumulate considerably more work while still creating a high oxidative demand.

This can be particularly important for an athlete who already has a high VO2max and whose limitation is the fraction of that VO2max that can be sustained. If fractional utilization is relatively low, increasing sustainable aerobic power may be far more important than trying to push VO2max another few percent. For that athlete, a greater amount of threshold work may make very good sense.

But that is an argument based on the needs of the athlete, not an argument that threshold is inherently a better training intensity or that we recover from it more quickly.

Lactate clearance and resynthesis is another area where I think training discussions have become confused. We often hear that threshold training is necessary because the athlete needs to train to “clear lactate.” I have always had a problem with this explanation, because it is neither accurate nor scientifically valid. Remember, it is lactate we are talking about, not lactic acid, as many refer to it.

Lactate is not a waste product that suddenly appears at threshold and then needs to be removed. It is being produced, transported and oxidized all the time, at all intensities, and it is an important fuel. Endurance training improves the ability to transport and oxidize lactate, but there is no reason to believe this only happens at threshold. High-intensity interval training also improves lactate transport and can move lactate threshold substantially.

VO2max intervals also create very high lactate production and turnover. So if we are looking at the lactate shuttle, why would it only, or even preferentially, adapt when lactate is sitting around 2, 3 or 4 mmol? That doesn’t make much physiological sense to me. Producing higher levels of lactate will stimulate resynthesis.

The same is true for mitochondrial biogenesis, oxidative enzymes and capillarization. We cannot neatly assign these adaptations to one training zone, because there is considerable overlap between endurance, threshold and high-intensity training.

That doesn’t mean all intensities are the same. They clearly aren’t. It means we should be careful about inventing unique adaptations for a training zone simply because we have given that zone a name. Threshold training is not the only method, or even the optimal method, to improve lactate oxidation and resynthesis.

A University of Vermont skier on rollerskis at Craftsbury Outdoor Center in October 2025. Autonomic, glycogen, muscular and mechanical recovery all run on different clocks. (Photo: Phillip Belena/EISA)

What Is Recovery?

Another problem in this discussion is recovery. People will say that threshold is easier to recover from. Maybe, but recover from what? Autonomic disturbance, glycogen depletion, neuromuscular fatigue, muscle damage, mechanical load, dehydration or psychological fatigue? These are not the same thing, and they do not necessarily recover at the same rate. A 2-hour run and a 2-hour rollerski at the same intensity, for example, carry very different mechanical loads to recover from.

HRV may tell us something about autonomic recovery, which should also reflect other aspects of recovery but does not specifically measure them. Resting heart rate can tell us something, but again not everything. Blood lactate tells us something about what is happening during and immediately after the workout, but remarkably little about whether the athlete is going to train well 24 or 48 hours later. Creatine kinase may tell us something about muscle damage, but there is huge individual variation. So when we talk about recovery cost as if it were one number, I think we are being too simplistic.

This is also why I don’t think we can simply use TRIMP, EPOC, duration, distance or session RPE to say one workout takes longer to recover from than another. They can give us useful information about internal load or physiological disturbance, but they are not recovery measurements. Ultimately, recovery must be considered in terms of which physiological systems were stressed and, more practically, what the athlete can do in the days immediately after a hard workout.

Carbohydrate use is another good example. VO2max exercise clearly has a higher rate of carbohydrate use per minute than threshold exercise. But once again, the session matters more than the minute. Twenty minutes at VO2max intensity may have a very high glycogen cost per minute. Forty, fifty or sixty minutes at threshold has a somewhat lower rate, but it is sustained for two or three times as long. We cannot automatically assume that the shorter VO2max workout creates greater total glycogen depletion.

This becomes particularly important when athletes are doing regular quality sessions. If glycogen restoration is an important part of recovery, a long threshold session may impose a very substantial recovery requirement despite producing lower lactate concentrations and feeling much more controlled. An athlete does not have to be lying on the ground after a workout for that workout to have been expensive to recover from.

That is one of the problems I see with the idea that threshold can be repeated frequently simply because lactate is controlled. Low lactate does not necessarily mean low glycogen use, low muscular load or rapid recovery. If we keep extending the duration of the threshold work, at some point the additional work has a cost.

Which brings us to what I think is probably the most meaningful recovery measure, and one that is surprisingly rarely studied: can the athlete perform the next important training session at the expected level?

Lucas Wilmot, Kristen Bourne, Murphy Kimball and Tabor Greenberg after their first L3 intervals at a 2025 camp in Bend, Oregon. (Photo: Leann Bentley)

An Interesting Study

One of the more interesting comparisons was made by Seiler, Haugen and Kuffel with highly trained runners. On one occasion the athletes did a threshold session of around 30 minutes between the first and second ventilatory thresholds, and on another, six three-minute intervals at around 95 to 96 percent of VO2max. I would point out that 95 to 96 percent of VO2max is already hard, and above what I would normally call a controlled VO2max session.

The differences between the workouts were substantial. Lactate during the threshold session was around 2.7 mmol, while during the VO2max intervals it was around 7.1. Perceived exertion was also much higher during the VO2max workout. By almost any acute measure the VO2max workout looked harder, so we might reasonably expect recovery to take longer. But HRV recovery following the two sessions was remarkably similar.

Now, this study does not fully answer the question. The threshold work was only around 30 minutes, HRV measures one part of recovery, and there are all kinds of differences between athletes. But it does challenge an assumption that I think is important. Greater acute metabolic disturbance does not necessarily mean longer recovery, but the dose does.

It also raises what I think is an even more interesting question. What would have happened if the threshold session had contained 40 or 50 minutes of work rather than 30? That would be much closer to the threshold sessions many trained endurance athletes are actually doing.

U.S. Biathlon coach Armin Auchentaller with Campbell Wright during summer training in Livigno, Italy, in July 2025. A controlled VO2max session is about time at high oxygen uptake, not about producing as much lactate as possible. (Photo: Manzoni/NordicFocus)

Control of VO2max Training

There is another issue here that I think is important. A lot of people seem to think VO2max training means going as hard as possible. It doesn’t, at least not the way I see it and use it.

If I give an athlete 5 x 4 minutes of VO2max work, I am not asking them to race every interval or see how much lactate they can produce. I am trying to get them to accumulate time at a very high oxygen uptake, typically around 90 to 95 percent of maximal heart rate and VO2max.

If the objective is a cardiovascular and oxidative stimulus, we need sufficient intensity to drive oxygen consumption toward a very high fractional utilization of VO2max. For many athletes, something in the range of 90 to 95 percent of VO2max may be enough to accomplish that. Once we have produced the stimulus we are looking for, going harder does not necessarily make the workout better.

This becomes important when we compare threshold and VO2max training. If someone compares a carefully controlled threshold session with a set of VO2max intervals performed as hard as possible, then of course the VO2max workout is going to look very stressful. But that may simply be a badly controlled VO2max workout.

A well-controlled VO2max session and an all-out interval session are not the same workout, just as a controlled threshold session and a threshold session that slowly turns into a race are not the same workout. Anyone who has coached for very long has seen both.

A University of Vermont skier on the rollerski track at Craftsbury in October 2025. Forty minutes at threshold is a lot of work, and so is fifty, and so is sixty. (Photo: Phillip Belena/EISA)

What Is Threshold’s Real Advantage?

In my view, the strongest argument for threshold training is not that it produces some special adaptation, but that athletes can accumulate a lot of high-quality aerobic work. Forty minutes at threshold is a lot of work. Fifty minutes is a lot of work. Sixty minutes is a lot of work. For an elite endurance athlete doing a very large total training volume, that may be exactly what is needed, provided the athlete can recover from the overall workload of the training period.

Threshold gives us a way to accumulate a substantial amount of work at high oxidative fractional utilization, with considerable muscular recruitment and a lot of sport-specific work. For an athlete with a high VO2max who needs to improve fractional utilization or sustainable aerobic power, this can be valuable.

I think this is where some of the current discussion around threshold becomes problematic. Because it is controlled, because lactate is relatively low, and because the athlete is not destroyed afterward, threshold starts to be treated almost like endurance training. It isn’t. It is still hard training, and if you do enough of it, it carries a substantial training load and potentially a substantial recovery cost.

The question is not simply whether forty or fifty minutes at threshold creates more adaptation than twenty minutes of VO2max work. It probably creates more of some kinds of stimulus simply because we are doing so much more work. The more useful question is whether the additional adaptation we get from that extra work is worth the additional load and recovery cost.

Kevin Bolger in the fog at the Oslo World Cup mass start in March 2026. The first question is what adaptation an athlete needs. The second is the smallest dose that will produce it. (Photo: Authamayou/NordicFocus)

Are We Asking the Wrong Question?

The debate is usually framed as threshold versus VO2max. Which is better? I don’t think that is the right question. The first question should be what adaptation this athlete needs. The second, and I think this is more important, is what is the smallest dose capable of producing that adaptation? It isn’t necessarily 40, 50 or 60 minutes. The third is what effect that dose will have on the training the athlete can perform over the next several days.

We tend to assume that if some training is good, more of it must create a greater adaptation. Up to a point that is probably true. But the objective of training is not to produce the largest possible stimulus in every workout. It is to produce enough stimulus to create the adaptation while still being able to absorb the rest of the training.

If an athlete has a relatively low VO2max and that is limiting performance, perhaps 15 or 20 minutes of controlled VO2max training gives us exactly the stimulus needed. If that is enough to stimulate the adaptation, why do 50 minutes of threshold just because threshold is currently popular?

On the other hand, if an athlete already has a very high VO2max but relatively poor fractional utilization, and cannot sustain a high percentage of it, then perhaps a larger volume of threshold work is exactly what is required. In that case the ability to accumulate 40 or 50 minutes at high aerobic flux may be the important stimulus.

NENSA athletes rollerskiing together in Craftsbury, Vermont. A workout can look great on paper and still be the wrong choice if it costs the next two days. (Photo: Chris City)

The Training Week Matters More Than the Workout

I also think we make a mistake when we look at workouts in isolation. A workout can look great on paper and still be a poor training choice, because the real issue is not simply what happened during those 60 or 90 minutes. It is what that workout allows us to do over the next several days.

Suppose a threshold workout produces 10 percent less adaptive stimulus than a VO2max session but allows the athlete to train substantially better over the following two days. Threshold may clearly have the better stimulus-to-recovery ratio and therefore be the better choice.

But reverse the situation. Suppose 20 minutes of well-controlled VO2max work produces the adaptation we want and the athlete is ready to train normally the next day, while 40 or 60 minutes of threshold creates substantial glycogen depletion and muscular fatigue. In that circumstance, the shorter VO2max workout may have the better stimulus-to-recovery ratio.

We shouldn’t decide the answer beforehand simply because one workout carries the label “threshold” and the other “VO2max.” Threshold is not automatically low cost, and VO2max is not automatically high cost. The dose matters, the athlete matters, the training done before the session matters, what needs to be done after the session matters, and the total training week matters.

Therese Johaug racing the mass start at the Lahti World Cup in March 2025. Even races of up to 90 minutes, Galanes says, are often skied well above threshold. (Photo: Thibaut/NordicFocus)

Dose, Adaptation and Recovery

I am certainly not arguing against threshold training. Rather, I am arguing that the dose needs to be controlled relative to the individual athlete, and that the time to recover is not what is often suggested. I use threshold with athletes who need it, and it can be effective. But I do think we need to be more careful about how it is being presented. It is not automatically what every athlete needs.

Threshold and VO2max training have different characteristics, but their physiological adaptations overlap substantially. VO2max training provides a very large physiological stimulus in a relatively short period of time and appears particularly useful when maximal aerobic capacity is what we are trying to improve. Threshold allows us to accumulate considerably more work at a high aerobic output and can be extremely effective when sustainable aerobic power or fractional utilization is the limitation.

Both can be valuable, and both can be overdone.

In my experience, especially over the last decade, I have seen far more athletes become flat, stale, overtrained or simply stagnant from doing too much threshold training than from doing properly controlled VO2max work. Usually it comes from doing too big a volume of threshold work, too often. That doesn’t mean threshold is bad. It means threshold must be appropriately prescribed and dosed.

I also think the very large amounts of threshold work we sometimes see promoted are primarily appropriate for highly trained elite athletes who are also doing very large overall training volumes and have spent years developing that volume. I would be much more cautious applying the same model to younger athletes, developing athletes, masters athletes, or anyone doing a much smaller overall training volume.

There is another point that seems to get lost. Athletes racing 5, 10 and 15-kilometer events are not racing those events at threshold. I have decades of data showing that even in races of up to 90 minutes, fractional utilization can be well above threshold. The shorter races are at a very high intensity, in what is defined as the VO2max zone. At some point we need to train that capacity directly. Doing more threshold work because it is supposedly lower cost does not eliminate the need to train at race-relevant intensity.

In the end, I think we need to get away from ranking training zones as good, bad, safe or dangerous, and think more in terms of dose, desired adaptation and recovery. What are we trying to adapt, what dose is needed to produce that adaptation (often less than we think), and what does that dose cost us in terms of the training that follows?

The most valuable workout is not necessarily the one that creates the greatest immediate physiological disturbance, nor is it necessarily the one that accumulates the most minutes around some predetermined lactate value. It is the workout that provides enough stimulus to produce the adaptation we are looking for while preserving the athlete’s ability to absorb the rest of the training program.

In the end, that is the balance we are trying to find.

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September 23, 2026

When to Increase Training Load… and When to Wait

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American Neve Gerard (l) leads athletes from other countries at an International Training Camp in August, 2024, in Sjusjøen, Norway. (Courtesy photo)

As this ski season wraps up, many of us coaches are doing similar work. Using spreadsheets or a popular training platform, we map out training for the year. We plan the yearly hours, monthly hours, and weekly hours, along with defining the training intensity distribution. We also plan how long and over-distance sessions should be, and maybe how much high-intensity training we should include, etc. I have done the same in the past.

Nowadays, my yearly plans include almost none of those things, but rather it is a general road map of how I might want the training loads to progress, what type of high-intensity, neuromuscular work, strength training focus, technique development, training camps, testing sessions, and a general concept of where we start in April or May. We must be able to adjust training on the fly based on an assessment of how athletes’ recovery and adaptation, week to week, with the training and developing fitness.

In this article, I want to make a case for the changes I have made. Why? Because these detailed hours and training-intensity distribution plans we make are about as good as the day they were written. We then must avoid the temptation to implement training in May, June, or July just because we wrote it down in April. There is no way we can anticipate in April how an athlete will respond to training next month, much less than 2-6 months down the road.

In discussion with many athletes and coaches I have consulted with in the last four to five years, I believe the biggest challenge faced is how and when to increase training load within a training year. For reference, I use TRIMP to define the metabolic load. TRIMP is described as a modeled internal-load metric or composite index based on exercise duration and HR-derived intensity weighting. TRIMP is not perfect because it is based on heart rate parameters, so power and strength training, mechanical loads are not accounted for. I find TRIMP an excellent proxy for the loads of all endurance training.

Bates College getting after some dryland in 2024. (Photo: courtesy photo)

Others simply use hours to plan and measure the loads. The challenge is difficult when just looking at hours, how to compare an hour of easy training versus an hour of hard training. Then, looking at percentages of time in zones or with other training methods does not define the load or focus the training on the desired adaptation.

I am not going to address the year-to-year increases simply because all the assorted tables recommending volume of training at an age are based on population averages. The goals of the athletes, the athletes’ training age, training history, and many other potential factors. Just assigning training based on a table is foolish without considering these other factors. In most cases, athletes will train enough if the right principles are followed.

When we are coaching athletes, we should only increase loads because of improved fitness not in an attempt to drive fitness gains. The decision to increase loads should come from evidence that the athlete(s) have absorbed the current load, not simply because it is a new month and the plan calls for a month-over-month increase. I believe that in the past we have used templates or models that have called for big month-to-month increases. The basis of building fitness is consistency and adaptation to the training. In many cases, we can go as long as 2-3 months at a very similar or very small increase in load.

I am far from certain how coaches plan training these days, but others and I in the past have planned training based on monthly and weekly hours. In my days, I used to start in May with 50 hours, and by November, I was training more than 100 hours. Then the weekly progression within those months might go 12 hours, 14 hours, 16 hours, 10 hours or something like that. Even back then, how does a 50-hour month prepare you to do a 60-hour month, how does a 12-hour week prepare you to do a 14-hour week? What I learned more than 30 years ago. It doesn’t work that way; even if an athlete completes that kind of protocol, it does not mean it worked; it just means they survived it.

The research and experience suggest that higher monthly volume and small periodic increases are better for building long-term fitness and performance, with far less risk than the typical plans that ramp up training with increases of 10-15-20% per month. Many old-school thoughts persist that we must increase volume to stimulate further improvements. That is an invalid belief and has been shown to be in much research and analysis. If we are in fact building fitness, we are moving faster at every intensity. Isn’t that already an increase in load? Recruiting more muscle fibers and motor units aerobically, improving mitochondrial density and function, improving aerobic enzymes in more muscle fibers, among other aerobic adaptations.

Fin Bailey works on uphill technique at training camp. (Photo: courtesy photo)

I look for three layers of signals: performance stability, physiological response, and behavioral cues.

The stability of performance in training is easily measured with simple technology, such as heart rate and GPS. Prior to increasing loads, the athlete should show improvement or stable performance in workouts. The aerobic training sessions should feel consistent and easy, with very little or no heart rate drift through the workouts. So, a simple training session once a week, once every two weeks, around a standard loop, both for high-intensity and aerobic training, can tell us much.

The key workouts should show repeatable performance levels from week to week. The pace athletes can maintain at aerobic intensity should gradually and slowly improve, and the technique should stay stable and efficient throughout the workouts.

Indicator	What it suggests
Same HR but faster pace, HRV is improving	Aerobic adaptation
Same workout feels easier, HRV is stable or improving	Load is absorbed
Ability to repeat intervals without extra fatigue	Ready for progression
If workouts are still producing large fatigue swings, the system is still adapting and increasing load is premature.

As I have written previously for FasterSkier, older junior ( U18’s) athletes, masters, and elite athletes, I think it is important to use HRV to assess recovery. Using HRV, we can see whether the athletes are recovering predictably between sessions. We can see the stability or improving response their training, and we can assess whether the training loads are sustainable.

Useful signals:

Resting HR stable
HRV 7-day trend stable or improving
Sleep quality normal
Muscle soreness minimal after aerobic sessions
The data and the athlete reports feeling normal again within ~24 hours

If recovery between sessions is incomplete, increasing load compounds fatigue rather than builds fitness. The rush to hit hourly objectives and the failure to respond to accumulating fatigue are the biggest causes of maladaptive training.

The critical question HRV can help to address. Are the current loads the athlete is doing correct? HRV, especially RMSSD trends collected consistently, can help flag whether an athlete is tolerating training well. But HRV should be interpreted alongside performance, subjective recovery, resting HR, sleep, and life stress rather than used as a standalone decision rule. In some cases, this may mean adjusting other areas of life; in others, we may simply have to reduce the training loads. Simply low HRV indicates a compromised ability to recover from and adapt to training

A good indicator of readiness is the athlete’s ability to handle training density. Most athletes should have at least one rest day per week. During a training period, the athlete should be able to handle 3-5 moderate training days in a row without feeling accumulated fatigue, and the quality of workouts remains normal and stable.

The occasional longer sessions should not disrupt the next day’s planned training, and recovery should be normal the following day. If an athlete is doing double sessions, the second session of the day should not be carrying excessive fatigue from the morning session, and the quality, speed, pace, or intensity of the second workout should be consistent.

When the athlete’s readiness and physiological measures indicate that an increase in load is appropriate, there should only be a slight increase in volume. Make a few sessions per week a little bit longer, followed in the future by adding a workout or two per week

Training load should only increase when the muscles and connective tissue are tolerating the training. If there is persistent tendon soreness, joint irritation, muscle tightness, or recurring niggles are common, it is not appropriate to increase the loads. Aerobic fitness improves faster than structural durability, which is why injuries often appear right after a volume jump.

We also need to be aware of and watch for behavioral cues in the athletes, not just the recovery and performance data. We should look for the athlete’s motivation to train and their assessment of the RPE (rating of perceived exertion) for a given workout. If the perceived exertion of a given workout is increasing, it is not a positive signal. Finally, we should ensure that athletes’ nutrition is good, and their body weight is stable.

As a practical guideline, I would recommend increasing load only after a period of 3-6 weeks, where we can see stable adaptation and improvement in training and recovery measures. When we look at elite training, we always see the training progression is often much slower than people expect.

JC Schoonmaker and Luke Jager training in Anchorage, Alaska back in 2023. (Photo: Brinkema Brothers)

Training Phase	Progression Pattern
Base Phase	+5–10% volume every 3-6 weeks, but only if all inputs are positive. If using TRIMP or Training Peaks TSS the load increase should never exceed 15-20%
Race Prep Phase	Maintain a stable volume, intensity increase slowly from the base phase
Competition phase	Volume and Training load decreases slightly; intensity is maintained or increased due to race load.

As useful guidelines for coaches. If a training day or a week feels heroic, it is too big. Most likely, all the heroic training did was build fatigue and greatly slow recovery and adaptation. Sure, the athlete can do it occasionally, but it in no way means the load improves fitness or performance, or that the athlete adapts to it. My rule of thumb is that the longer it takes for an athlete to recover from a workout, a week, or a month of training, the less adaptation that is possible. When I shared this comment regarding high-intensity workouts with Zach Caldwell, I asked him when we should adapt to them. His response was Thursday! Not next Thursday, not a Thursday next month. Thursday!

An effective training progression should feel well-tolerated for weeks. Fitness improvements are built on consistent, manageable weeks. Where the fitness is developed through compounded training, not the occasional massive week. I have seen it repeatedly, it is big increases in training load, too much, too soon, that ultimately leads to declining performance and overtraining. Sure, elite athletes train massive weeks, but to get there, they adapt to training every year, step by step.

Increases in training load should be almost invisible over weeks and months as athletes develop. Over the years of training, the increases are clearly visible and large.

In summary, increase training load when:

Current workouts are repeatable and controlled
Athletes recover following training days, normally within ~24 hours
No structural soreness or injury signals
Motivation and energy are normal
This training performance has improved, and recovery has been stable or improving for 3-6 weeks

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French athletes Lucas Chanavat (left) and Maurice Magnificat (right) out for a rollerski during a training camp in Tignes. (Photo: NordicFocus)

April 8, 2026

Using Heart Rate Variability to Guide Training

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Training by the numbers: heart rate, exertion levels, weekly/yearly hours, and lactate monitoring are all part of the system that guides the training of Stifel US Ski Team Sprinter, Jack Young. (Photo: Courtesy Photo)

In my coaching and consulting work, I get a lot of questions about using heart rate variability (HRV) to guide training. This is a follow-up to a previous article, where I want to move from theory to practice and show how HRV has been one of the most valuable tools I’ve used to assess recovery and adaptation in endurance athletes.

There is no shortage of research documenting the value of HRV in endurance training. That’s well established. What matters to me is how it works in coaching practice. In my experience, HRV is especially useful for helping athletes avoid the most damaging downsides of poorly implemented training. Most of the big performance issues I have seen over the years could have been avoided with the use of HRV.

Over the years, I’ve collected long-term HRV data on many athletes, some spanning close to ten years. The example I’m using here covers nearly four years and serves as an excellent illustration of how HRV reflects training implementation, adaptation, and the consequences of training changes over time. This athlete was 50 years old at the start of the data set, but I’ve seen the same pattern in juniors, elites, and masters’ athletes alike. The trend is the same; only the absolute HRV values differ.

Most of the athletes I’ve worked with over the past 15–20 years arrived with either inconsistent training or worse, chronic over-training. In this example, training lacked consistency and relied too heavily on endurance work performed at intensities that were simply too high. To be clear, many of the long-term problems I’ve seen, performance stagnation, recurring illness, persistent fatigue, would have been obvious much earlier had HRV been used properly.

The chart below shows an overview of the data, collected using a Firstbeat sensor and analyzed through the Firstbeat Sports platform. With improved training structure and better implementation, this athlete’s RMSSD baseline steadily increased:

2022: ~45 ms
2023: ~55 ms
2024: ~65 ms
2025: ~75 ms

For anyone familiar with HRV, these are substantial improvements. From a health and wellness perspective, they’re meaningful. From a performance perspective, they’re even more telling. Population data suggests that an RMSSD of around 75 ms is very good for someone in this age group. Performance metrics tracked alongside this, ski erg tests and six-minute roller ski tests, showed parallel and consistent improvements over the same period.

Some people will point to what looks like large day-to-day variation in the data. Yes, the coefficient of variation can appear wide at first glance. In athletes with low or suppressed HRV, I often see variability in the 20–30% range. As fitness and autonomic stability improve, that typically narrows to the 10–20% range. So, while the spread may look dramatic, it’s often exactly what we expect. Larger variability usually reflects poor training implementation or an athlete drifting toward an overtrained state.

I’ve seen this same pattern repeatedly in underperforming and overtrained athletes, at both junior and elite levels. HRV is often much lower than expected. When training and recovery are corrected, athletes frequently feel better before their HRV confirms they are ready to resume normal training. This is a critical point. Returning too early, before HRV plateaus, is a common mistake. When training is reintroduced with proper control, HRV not only stabilizes but often continues to rise beyond previous levels.

Population-level HRV data can provide useful context. There will always be individual differences, but these ranges help determine whether an athlete is operating in a reasonable zone for their age. In practice, well-trained endurance athletes often sit above the “high” end of population norms. I’ve coached athletes in their 20s with RMSSD values consistently in the 110–120 ms range. The same 50-year-old athlete referenced here now sits closer to 75–80 ms.

Normal Resting RMSSD Ranges by Age

(Morning, seated or standing, ECG-based measurement)

Age	Low / Suppressed	Typical / Normal	High / Very Good
<20	<50 ms	60–90 ms	>90 ms
20–29	<40 ms	50–80 ms	>80 ms
30–39	<35 ms	45–75 ms	>75 ms
40–49	<30 ms	40–65 ms	>65 ms
50–59	<25 ms	35–60 ms	>60 ms
60–69	<20 ms	30–50 ms	>50 ms
70+	<15 ms	25–45 ms	>45 ms

To make HRV actionable, the data must be analyzed correctly. I typically use a seven-day acute average of RMSSD and establish a normal range using a standard deviation of ±0.5 over a two- to three-month period. When training is well implemented, we expect to see a gradual upward drift in HRV. Eventually, HRV will reach a physiological ceiling, and further increases won’t occur unless the athlete is recovering from illness, injury, or prior overtraining.

In a healthy training state, the acute HRV average should remain within that normal range. If it drops below, the first step is always context: life stress, sleep, travel, illness, or recent training load. Sometimes it’s a conversation. Other times, it’s an immediate adjustment to the plan.

Daily fluctuations are normal. Hard sessions or unusually long workouts often cause short-term drops in HRV, and that’s not a problem provided values don’t fall well below baseline. What matters is the seven-day trend and whether that trend begins drifting downward.

Chronic suppression tells us several things:

the autonomic nervous system is not recovering
training stress exceeds adaptive capacity
intensity distribution is likely wrong, even if volume looks reasonable

This is where HRV is most powerful. It catches problems early, before performance falls apart. Large single-day drops can also flag oncoming illness or signal the need to review the previous few days of training.

HRV often exposes poor intensity distribution long before performance declines. Athletes can hold things together for surprisingly long periods while autonomic stress accumulates underneath. HRV shows that the effects early, particularly in athletes doing too much work in the higher intensity zones.

This is especially relevant for junior and masters’ athletes, where recovery margins are smaller and the consequences of mistakes are greater.

I will not increase training load, weekly or monthly unless the acute HRV is at baseline or higher (the midpoint of the error bars). This is one of the most common issues I see when consulting with athletes and coaches: loads are increased according to the plan, not according to how the athlete is recovering and adapting.

JC Schoonmaker and Luke Jager training in Anchorage, Alaska. (Photo: Brinkema Brothers)

Both experience and research are clear here. Increasing load or adding high-intensity work when HRV is suppressed does not lead to adaptation. I’ve worked with athletes whose acute RMSSD dropped 20–30 ms below normal for weeks or months, with the expectation that a short taper would fix it. At that point, the system is deeply suppressed. It often takes weeks or months for the nervous system to normalize and for performance to follow.

RMSSD is a valid marker of systemic stress. When HRV is low, the body is not positioned to recover from or adapt to training especially high-intensity work and racing. The daily process to collect and review this data takes less than 15 minutes.

The protocol is simple. The athlete wakes up, uses the bathroom if needed, then puts on a chest strap and sensor. In a seated or standing position, they remain still for a minute to allow heart rate to stabilize, then complete a three-minute test. I discourage optical sensors for HRV; they do not provide true ECG-based data. Sitting or standing introduces a mild orthostatic stress, which reduces variability and improves readiness assessment. We used supine testing for years and found far greater noise.

Use reliable software, Firstbeat, Kubios, or one of Marco Altini’s phone-based applications to analyze the data. I export everything to Excel to dig deeper into respiration, coefficient of variation, and resting heart rate.

If the goal is to prepare athletes optimally, manage recovery, and understand when they are truly positioned to perform, HRV is not optional. It’s inexpensive, easy to use, and one of the most valuable data streams we can collect.

HRV doesn’t make training smarter.
It is exposed when we aren’t smart already.

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Bates College skiers getting after some dryland training.

January 27, 2026

Quantifying Recovery: An Intro to Heart Rate Variability by Ned Dowling, PT

Ian Torchia (SMS T2) pushes through a set of double pole intervals. (Photo: Tom Horrocks / Instagram @fullytorched)

As endurance athletes, and especially as cross country skiers, we like to suffer. We enjoy a sport that takes place in the coldest months of the year and requires both strength and endurance to climb big hills and descend on skinny skis with no edges. We like to breathe hard. Most of us are in it for the suffering and the healthy dose of chemicals that our bodies release when the heart rate goes up and the muscles begin to burn. The runner’s high, an endorphin rush, pick your preferred phrasing.

Hopefully, we’re smart enough by now to know that we can’t go hard all of the time, at least not without consequences. The really smart among us are able to listen to their bodies and know intuitively when they can step on the gas and when they need to back off. But the rest of us could probably benefit from some type of external governor besides the voices in our heads egging us on, or constantly available Strava competition taunting from inside our pocket.

If life was just eat, sleep, and train, the calculus of easy/hard or short/long might be pretty easy. But work, school, kids, relationships, global pandemics, and social media bring no shortage of life stressors. And, physiologically, these life stressors can load the body just the same as an interval session. Stress is stress, and stress takes a toll on the body.

So, your training plan might call for a hard session, but what if work was crazy, the kid kept you up all night, and you made the mistake of reading the news headlines this morning? Is your body in the right place to make the workout productive? (Or at least not detrimental?) How do you know?

I think the honest answer is that we don’t always have an answer, but there are some metrics that can help us shape a well-informed guess.

Since Polar introduced the first functionally useful heart rate monitor in 1984 and Garmin gave us the GPS watch in 2006, wearable training technology has evolved considerably. Current wearables can track — and thus quantify — everything from steps to sleep to intensity. I don’t dare dive into that vast sea except to highlight and discuss what metrics might be the best at answering our question, “How hard should I push myself today?”

But before we even get there, it’s worth having a quick refresher on some principles of training, exercise, and activity. Depending on your goals, Nordic skiing can be an activity that simply gets you out in nature, a tool to maintain fitness for other sports like cycling or running in the winter, or it can be a year-round focus with time on snow dichotomized into either training or racing. In any of these scenarios, the cumulative load on the body is a very important variable to manage.

Too much load and we stop having fun, plateau or lose fitness, and begin to risk injury. Too little load and we don’t progress, but I doubt that’s an issue with the majority of us. We must also remember that the basic recipe for improving strength and fitness is load + recovery = adaptation. Or as Brad Stulberg and Steve Magness phase it, stress + rest = growth.

Lina Sutro (SMS T2) models the female skier’s signature “heart rate monitor tucked under sports bra band” look while training in Vermont. (Photo: Julia Kern)

Our bodies respond to load by making adaptations, but if we go too hard too often, and/or take too little rest and recovery, the equation becomes out of balance. We lose out on adaptation, and thus our capacity for improvement stalls out.

Strategies like polarization and periodization aim to apply the load/recovery equation to maximize the training adaptations and improvements. Briefly, polarized training is the division of activities into either “hard” or “easy” intensity in roughly a 20:80 ratio. There is no “moderate.” The premise being that moderate efforts are neither hard enough to stimulate adaptations nor easy enough to allow to develop aerobic pathways or for active recovery — putting in “junk miles”, as it’s often described.

In a periodized training program, polarization is taken a step further with hard and easy sessions layered together over longer cycles (think weeks and months). A periodized training plan builds progressively toward a goal race, followed by a period of time following the event that is focused on rest and unstructured training.

During that macrocycle, the split of your weekly training might stay roughly at the 80/20 ratio, but every third or fourth week might be recovery-focused, with a lower volume than the previous weeks. This three to four week block might be called a microcycle. On average, the easy-to-hard ratio is the same, but the overall load of the week is lower, allowing the body to adapt and repair. (And you can catch up on your laundry.)

These fundamental concepts should be incorporated in any good training strategy, whether it’s a week-by-week homemade plan or a comprehensive annual program from a coach. But, just because the plan is intended to provide a roadmap for loading and resting doesn’t mean we will always get the implementation right.

This is not the coach’s fault. It’s life’s fault. A training program is written to balance training load and frequently doesn’t account for the additional stressors of work, school, or family. Stress is stress, regardless of the source. We can’t achieve the intended balance in training if we are over-tired from traveling for work, have been chasing our kids around all day, or burned the midnight oil trying to get our work done when our kids’ school is shut down. Similarly, pushing too hard when we should be going easy leaves us over-cooked before an interval session, deeming it unproductive. But how do we gage the load our body’s have been under?

(If you read the previous paragraphs and said, “This is stupid, I just want to ski” I don’t blame you. I don’t think everyone needs a rigid or even dichotomized workout schedule. However, if all of your exercise is at a hard intensity your risk of injury is increased so you might consider rethinking your strategy. If all of your exercise is at moderate intensity, then you’re just unlikely to get faster. For a lot of people, that’s not a priority, which is perfectly fine and you shouldn’t be judged or dissuaded. Go have fun!)

From l to r: Simi Hamilton, Erik Bjornsen, Ian Torchia, and Paddy Caldwell of the U.S. men’s team during a 2018 rollerski up l’Alpe d’Huez in France. (Photo: Chris Grover)

There’s an old proverb in bike racing about burning matches. Everyone on the starting line starts with the same number of matches. During the race, matches are burned quickly by riding at the front, attacking, covering attacks, and just riding above one’s threshold. At the end of the race it’s often not the strongest rider who wins but the one who burns the least matches (the 2021 men’s Paris-Roubaix is a perfect example).

We, too, start the day with a set number of matches that we’ll burn up with road rage, frustrations at work, frustrations at home, social media FOMO, and of course training. The number of matches we get each day is directly related to how rested and recovered we are heading into the day, both mentally and physically. Exactly how many matches are in the box goes back to recovery, and, once again, to our original question: “How hard should I push myself today?”

If your matches are burnt up before you head out to train, the answer might be “Not very,” regardless of what the training plan says.

One of the earlier attempts to answer this analogue question with a binary “hard or easy”, was resting heart rate. It’s a simple concept: Take your heart rate every morning for a few weeks and calculate an average. If your heart rate has increased by more than 5 beats per minute from the average, then your inventory of matches is not fully replenished. While this article won’t go deeply into the details, there is some research to indicate that resting heart rate doesn’t correlate that well with fatigue levels. This article from Marco Altini goes into significant detail on the topic. (If you follow that link, you’ll find that you’ve arrived on the last of a five part series on Heart Rate Variability. Dr Altini is one of the leading experts and innovators in the field, you may find his articles to be more robust than one you’re currently reading.)

Relative Effort, TSS, EPOC, PTE, CTL, ATL, are all metrics generated by modern wearables to quantify training load and, therefore, stress on the body. These numbers are based largely on heart rate and duration: the higher your heart rate and the longer you keep it there, the more points you score. This is certainly useful information, especially with regards to periodization and keeping track of hard vs easy training sessions; however, it only gives you one number in the load + recovery = adaptation equation.

Gus Schumacher and Kevin Bolger, heart rate straps on and up, bump fists after a training session in Soldier Hollow. (Photo: Simi Hamilton / Instagram @gus.schumacher)

We still haven’t answered the question, “How hard should I push myself today?”The same device or app that gave you a training load score will likely give a number for recovery status or a time needed to recover; this evaluation is typically still based on average heart rate during training and the overall duration of the previous session(s). It does not take into account the other life stressors. Enter Heart Rate Variability (HRV).

In a nutshell, HRV is a measurement of the time between heart beats rather than the number of beats itself. More specifically, HRV looks at the inconsistency of timing between heart muscle contractions.

Heart rate is governed by the autonomic nervous system, or the division of the nervous system that is responsible for body functions that happen automatically. This is the same part of the nervous system that controls things like temperature regulation (sweating and shivering) and digestion — bodily functions that we don’t have to consciously think about to make happen.

The autonomic nervous system is influenced by the sympathetic nervous system — the “fight or flight” mode that upregulates the body to prepare for battle (heart rate increases, armpits get sweaty, digestion gets turned off, etc.), and by the parasympathetic nervous system, which calms the body down. Our bodies are programmed to seek homeostasis — that happy place where everything can function optimally. The sympathetic and parasympathetic systems work to maintain that balance.

HRV attempts to quantify that balance between the parasympathetic and sympathetic systems, and thus the measurement is a gauge of how the body is down-regulating versus up-regulating — homeostasis.

Somewhat counterintuitively, a higher HRV, which indicates more variability and less consistency in the time between heartbeats, is indicative of greater parasympathetic versus sympathetic influence on the autonomic nervous system. Looked at another way, the greater the stress on the body, the greater the influence of the sympathetic system, which decreases the variability in time between heartbeats and therefore equals lower HRV.

This infographic from Firstbeat Technologies, an industry leader in heart rate training science, modeling heart rate variability. (Photo: Firstbeat.com)

These days, there are many options for recording and tracking HRV: Whoop is a 24/7 wristband with an LED sensor that measures a gazillion things, but specific to HRV, the measurement is taken every night during sleep. The Oura Ring, which is used by some members of the U.S. Cross Country Ski Team, also contains an LED sensor and records automatically during sleep. HRV4Training has an app that turns the camera and flash of your smartphone into a recording device much like a pulse oximeter. EliteHRV uses a device that goes on your finger very much like a pulse oximeter. Firstbeat, who use a proprietary ECG style sensor, were one of the first commercially available HRV trackers on the market (as mentioned in a Nordic Nation podcast with Jim Galanes and in this old article from Zach Caldwell, which also discusses HRV in all the detail you’d expect from Zach).

With all platforms, consistency in recording is key so you can recognize patterns over time. The devices that record automatically during sleep (Whoop, Oura, and Firstbeat) have the advantage in being the no-brainers as long as you’re wearing the gizmo, but they have the disadvantage of being the most expensive. Both HRV4Training and EliteHRV require you to take the recording daily at a consistent time and in a consistent way. Ideally this is first thing in the morning (I go to the bathroom first then immediately sit down and record). I’m a creature of habit and since building this into my morning routine, I’ve not had much trouble incorporating the one minute it takes to record a daily HRV measurement. If consistency is going to be a challenge, invest in one of the automated devices.

This brings us to the utility of HRV: tracking the body’s response to stress over time. The emphasis here is over time. HRV can help answer our question, “How hard should I push myself today?”, but it’s not exactly a stoplight. Waking up to a low score doesn’t necessarily mean you should go easy if you still feel good, but waking up to a seven day average with a negative trend means you should probably skip the hard workouts until your HRV stabilizes. For example, both this paper and this paper found benefits to using HRV to modify training vs strictly following a periodized schedule.

From what we know about the metric so far, the primary goal is to keep HRV stable. If your training plan is appropriately balanced, you’re keeping life stressors in check, and your body is responding favorably, then HRV will remain fairly uniform, even after a hard workout. (A low HRV score after a hard session is definitely not a goal or badge of honor.) But if your HRV becomes unstable, especially a downward trend over at least a few days, that is when it really has the potential to catch an issue while it’s small, whether that’s due to training load, illness, or life stressors. Anecdotally, I’ve heard of notable dips in HRV with people just prior to illness (especially COVID) and after the vaccine. These are situations where maybe you’ve not yet become symptomatic — your body hasn’t started yelling at you — but it is already enduring stress, and the additional load from hard training is not going to be welcomed.

Ultimately, HRV is just another tool in the box. It’s not necessarily there to change what you do on any given day, at least not without subjective input on sleep quality, soreness, emotional state, and how much you drank last night. It’s best viewed as a safety device like anti-lock brakes on your car: if you’re always looking down the road and anticipating what’s to come, you might never need them. But sometimes, when we’re training hard and emotionally invested in our goals, it’s like driving through a snowstorm to make it home for Christmas. It can be easy to focus on the objective outcome and wanting to get there as quickly as possible, rather than slowing down and proactively adapting to the road conditions. Chances are, you’ll make it to your destination unscathed, but in the event that a deer runs across the road or you hit a patch of black ice coming into an intersection, the antilock brakes might help you stop and reset rather than crash.

As Jason Cork, World Cup Coach for the US XC Ski Team, put it, “I think it has some utility as long as you’re honestly also taking into account how you feel, how long you slept, energy, etc. I guess an analogy is if your HR at L3 is usually 180, and you’re super tired, it might be incredibly easy to hit 180 at an L1 velocity or incredibly difficult [to hit all-out velocity because HR is suppressed]. But the question really should be, ‘If you’re tired, why are you doing intensity?’”

Author’s disclaimer: I have no affiliation with any company that tracks HRV. I personally use the HRV4Training app, a Suunto watch, a Wahoo chest strap, and Strava, all of which I have paid for without discount.

December 10, 2021
Wednesday Workout: Masters Training Trips with Pioneer Midwest’s Brad Johnson

Brad Johnson, of Pioneer Midwest, skied his first Birkie at age 57 and made the race’s prestigious 25% Club (top 25 percent of age group) at age 60.

This Saturday, Jan. 20, the Masters World Cup will open in Minneapolis, Minnesota —the first time it has been in the U.S. in 10 years. Of course, the word “master” could be considered a euphemism for “old skier.” However, age doesn’t have to come with a decline in performance. Ask 65 year-old Brad Johnson, of Pioneer Midwest in Osseo, Minnesota. He raced his first American Birkebeiner when he was 57, and he’s done every one since.

As an employee of the Anoka-Hennepin school district before his retirement in 2009, Johnson acknowledges it was hard to teach, coach (track and nordic) and race. He was able to stay fit, “but you don’t get training in. I’d get home at 7-7:30, I’m not going out for an hour and a half because I don’t have anything left in the tank. Some coaches successfully do that.” He admits he was not one of them.

Johnson’s one of the “older-guy contingent” of Pioneer Midwest’s ski team, an “emeritus team of older guys that ski in Pioneer stuff.” Despite his late start to racing, he has made the Birkie’s 25% Club, with a top finish of 3:56 for the 54-kilometer classic, and he also completed the original Norwegian Birkebeiner. He credits his fitness to focusing on the basics: duration, frequency, and intensity of training.

He feels the main mistake masters skiers make is a focus on duration, not emphasizing frequency and intensity enough. “Those two- and three-hour skis can cause more harm than good,” Johnson said, citing a breakdown of technique as one fatigues, opening them up to injury. And, if you get too tired, you become more susceptible to illness.

“Illness and injury are the two things that shut us [masters] down more than anything,” he said.

Johnson typically skis about four days a week, with one core and weight-training session per week. He asserts the significant loss of muscle mass as one ages is central to maintaining some sort of strength regimen.

“You hit your 60s and it can go downhill real fast … use it or lose it, basically,” he said.

Johnson rests at least one day a week, but admits it can be as many as three, depending on weather.

Each workout, he focuses on one aspect of technique in conjunction with intensity, maintaining three aspects of fitness are integral to any workout: aerobic capacity, lactate threshold, and economy — the last an advantage of the master skier.

“We’ve done this [skiing] over and over again. We’ve become more efficient,” he said. “We’ve got a little bit more guile than some of these younger skiers.”

He calls it “skiing lazy”: saving energy as much as possible, using good form and drafting, something he’s done to 30-something skiers that “save[s] a lot of energy!”

Johnson incorporates Heart Rate Variability training into his workouts to help him get the best workout for any given day, but admits that is just one small piece of training. He feels one of the best things for the master skier is intervals — the number being based on how one feels; the use of a heart-rate monitor is imperative:

“We think we know where our heart rate is — we don’t have a clue, unless you’re wearing a monitor,” he said.

In Johnson’s opinion, a person should know their heart rate zones (1-5) in order to maximize the benefits of any workout.

Additionally, acknowledging that age can come with physical changes, Johnson suggests getting the OK from your doctor. “Assuming they know what they’re talking about, which isn’t always the case, and having a doctor that understand sports medicine and aging athletes,” he said. “That’s not the most common physician to find, but at the very least [one needs to establish], ‘is my heart in decent enough shape to go do this?’ ”

As Johnson is most definitely in “decent enough shape,” and showing no signs of slowing down, it would appear there is at least some truth in the old axiom: Old age and treachery will overcome youth and agility.

The Workout: Basic intervals

One of Johnson’s essential workouts is basic intervals, done on a variety of terrain, based on the technique he’s focusing on for the day. So, pick your “skill drill” (hills, double poling, etc.), and get ready for some intensity.

Warmup: Base on how you’re feeling for the day. Minimum is 5 minutes, but up to 20-30 minutes. Get into Zone 2; if you’re there, but don’t feel “ready to hit it” take more time until you do.

Interval Session: 8-12 intervals of 2-4 minutes in upper Zone 3 to Zone 4, in anaerobic threshold. Between intervals, ski easy until your heart rate is back into Zone 1. As soon as you are back in Zone 1, go into the next interval.

Be sure to note how long recovery takes for the first three or four intervals. The number of intervals you do is based on how quickly you are recovering; once your recovery time significantly increases, you are done. Johnson notes a recovery time increase of 30-45 seconds as significant.

For example: if it takes you 90-120 seconds to recover between the first few intervals, but by interval 9, it is taking you 150 seconds or longer, you are finished. By that point, Johnson says you have depleted yourself, technique can fall apart, and you can do more harm than good.

Warm down: (a.k.a. cool down) An easy ski back to the chalet — about 15-20 minutes, keeping the heart rate no higher than Zone 2.

January 17, 2018
And the Beat Goes On: Firstbeat Explained

If you want to be as cool and go as fast as Tad Elliott, you need to first buy a bad-ass El Camino and then next get a Suunto Ambit 3 heart rate monitor and Firstbeat HRV software.

This review of the Firstbeat heartbeat analysis system originally appeared on SlowTwitch.com, a publication targeted for triathletes (see Part I, II and III). This version has been added to and updated specifically for nordic skiers.

He says they’ve already got one…

Monitoring training load is the Holy Grail of endurance athletics. Any good coach will always be looking at how to optimize training load, and essentially every competitive athlete from the first time they toe the line will wonder how to best balance intensity, volume and recovery. Throw in the added and significant stressors of work, school and social obligations and this already complicated equation becomes even more involved.

As the world becomes increasingly digital and the science more precise, the last few years have brought a number of different technologies to the plate that look to better quantify training and recovery. Heart rate monitors have been a staple of endurance training for over three decades. With the increased prevalence of smart phones and their ever increasing functionality, the ability to collect data has never been greater. Even more recently, a speciality market of “fitness trackers” has emerged with devices 100 percent dedicated to tracking movement, heart rates and a variety of other metrics. Several of the big players like Apple have gone a step further (no pun intended) and incorporated these features into everyday wrist watches, so finding ways to clutter your hard drive and mind with biometric data is now easier than ever.

One area which is ironically much less clear however, is the overall effectiveness and utility of all of these devices. Your functional threshold power (FTP) on the bike is 407 watts? Great. Now what? I didn’t win bike races by having a better FTP than the other riders, I won races by getting to the finish line first. Same deal with heart rate. Now before all of you data geeks fire off an angry email that these metrics are tools to help better guide athletes to the podium, I agree with you, but what if there was something that allowed you to quantify both work and recovery? Something that provided insight into not just the physiological stresses of training but also in activities of daily living (ADL). There is. And it is called Firstbeat.

The Firstbeat system can be used with a traditional heart rate monitor chest strap or specially dedicated chest sensors as pictured.

HRV

The Firstbeat system (FB) is a member of a class of devices that monitor heart rate variability (HRV). In simple terms, HRV, as the name implies, is the difference in the intervals between heart beats. Different devices approach this situation differently, but in essence, Firstbeat uses a mathematical algorithm to compare heart rate, interval regularity, maximum heart rate and VO2 to calculate a few different output and recovery metrics.

How it works

One sport early to adopt HRV monitoring is nordic skiing. Three-time Olympian and former U.S, Ski Team coach Jim Galanes, offered his history with the device.

“Tina Hoffman, who was a coach at University of Alaska, Anchorage, showed this to me about eight years ago, so I’ve been studying this system for quite a while,” Galanes, who co-owns Galanes Sports Systems and handles the distribution, sales and service for Firstbeat products, explained on the phone. “The more I used it, the more convinced I became that it is a very effective tool and by far the best one out there. I’ve become so convinced of its effectiveness that starting four years ago, I won’t coach anyone who won’t use it; it is that powerful. It is the single best way to making training decisions.”

Zach Caldwell, coach of several members of the U.S. Ski Team, has been working with the system for a few years and provided a more in-depth explanation of the underlying science. “Your heart rate is governed by your central nervous system (CNS) through two central pathways in your autonomic nervous system: your sympathetic nervous system and your parasympathetic nervous system” Caldwell said on the phone. “Your sympathetic nervous system is what governs your ‘Fight or flight’ response, in common parlance. This is a stress response. It elevates your heart rate and creates a signal that makes the beat to beat interval very regular.”

Caldwell continued, “The second component, your parasympathetic nervous system, which governs rest and relaxation. The influence of the parasympathetic nervous system is to lower and create less regularity between heart beats. By looking at an individual’s heart rate (HR) variability in comparison their own baseline, you can make a statement about the prevalence of a sympathetic response, which is an indication of stress. In short, by using the Firstbeat system we can see how your body is responding to stress. It is a fairly direct measurement. I am not a scientist or a doctor, so while I have reviewed some of the literature, I can’t speak to the experimental design, but my read of the science is that there is ample support for the efficacy of utilization of heart rate measurements of indications of CNS function. CNS pathways are integral for heart rate regulation, so this is very pertinent for sports. Their appears to be very good science and very good efficacy of that science toward athletics.”

Galanes agreed, “A great deal of research, thought and testing has gone into this system: is the result of life work of Heikki Rusko, one of the best sports science researchers in the world, so the system is very well grounded in science, as the research that went into validating the system spanned over 15 years. From this perspective, unlike a lot of systems that are out there, this has gone through rigors scientific validation, both for monitoring training and recovery.”

The key, according to Galanes, isn’t just what the Firstbeat system measures, but what it does with it.

“There are a lot of systems out there that collect data, whether it is a regular heart rate monitor, power meter, Strava, Fitbits, whatever, but there is very little analysis that goes on with that data. Using HRV and the Firstbeat software to look at training load and recovery has become the gold standard. Power and HR are certainly useful, but alone they are not good measures of the disturbance of homeostasis on the body and that’s what training and recovery are all about.” For those interested in a much more in-depth presentation of actual data fields and a more detailed explanation and description of the software, check out this webinar: https://www.firstbeat.com/en/webinars/training-load-recovery-monitoring-in-professional-xc-skiing/

Why Use It

“Coaches and athletes are all very concerned with stress and recovery,” said Caldwell. “Previously I don’t think we have done a very good job at looking at this holistically, so while we looked at rest, we didn’t look at enough factors. The ability to examine and even quantify the role of stress both independent and related to training load is very powerful. This is particularly important for self-coached athletes, for as athletes, we tend to be good at lying to ourselves. Athletes are delusional. We take a lot of information on board and we interpret it based on what we want the outcomes to be. I see it all of the time. I can tell if an athlete is tired and I think even that athlete knows it, but when you ask them, they say they’re fine, in particular at the elite level. I work with over-motivated athletes who want to be able to do more. This isn’t a tool to tell you to take it easy, rather it is a tool to help you make better choices.”

Erika Flora, head coach of the Alaska Pacific University (APU) elite team, agreed. “It can be a good tool if used correctly and in combination with other indicators, in particular feel — I am a big believer in teaching athletes ‘feel,’ ” he said during an in-person interview. “HRV is not an absolute indicator, but it is definitely useful, as sometimes motivation overrides good judgment.”

The 24-Hour Athlete

So often the motivation to try harder is bundled into the four hours of training each day and the other 20 hours in the day are ignored, or at least not optimized,” theorized Caldwell. “If your job has had you running around all day, it may actually be counter-productive to do the interval session you had scheduled. This system is a tremendous help in monitoring your overall stress and adaptation. Careful and correct interpretation of this data can create what I call ‘better 24-hour athletes’.”

Caldwell continued, “One of the major things we want from training is to see a positive response. It sounds so basic, but I see so many good athletes mess this up. We want training to make you stronger. You do a hard training session, we hope that this will make you better, that’s the goal. It’s easy to skip the part where we ask, ‘Is this really going to make me better? If so, when?’ This is a tool to help answer the question. I am unconvinced by things for which I don’t see evidence. I see lots of people doing lots of hard work, but I don’t always see benefits. Why? Training should work. As a coach, if an athlete is not getting better, I want to know why. Why are they not responding positively to training? If we’re counting totally on self-reporting, well, that doesn’t work very well. Most of the good athletes I know have a very good way of coloring their own training. You can beat them into the ground with tests, but that also has its limitations and is disruptive. What if you had a tool that could quantify all of these factors. What if you knew who had good sleep and recovery? This tool does all of that.”

How to use it

Essentially the Firstbeat system measures two primary factors: training load and recovery. The two are obviously related, but can also be uniquely independent. Training load is monitored through a combination of factors, in particular, Excess Post-exercise Oxygen Consumption (EPOC). Measuring EPOC offers several advantages over measuring power or heart rate alone.

“EPOC is very interesting in that it helps you understand the load that you feel when you’re training is cumulative, not instantaneous,” noted Caldwell. “The cool thing about EPOC is that it looks at accumulation of effort over time. The best athletes have a great sense of how to keep things ‘easy’ — their HR can drift up a bit, but they can feel the recovery. What I see in less accomplished athletes is that they religiously follow the HR monitor, so sessions designed to be easy oftentimes aren’t so. Typically amateurs overdo it on easy days and under train on hard days. Using EPOC to help monitor this is huge.”

“Granted, my case is somewhat unique,” Caldwell continued, “as I exclusively coach elite skiers, so EPOC scores are useful, but the recovery thing is even more useful for me. The recovery score is great because it utilizes HRV as a real-time score. The recovery score is an indication both of the level of recovery and the level of fitness. You can’t rest your way to a great recovery score any more than you can rest your way to a great performance. Your peak recovery scores come in relation to your peak training loads and your best management of the recovery process, so it’s not just rest – paradoxically it is also training load.”

Galanes followed up on this thought: “This system is based on understanding each individual’s unique physiology. To use this system optimally, you need to start out and do some testing programs on things like max HR and help determine max VO2. So you need to do a six-minute max test. This helps set a good benchmark for all of the data. This is key, as you need good data going into the system at the start. Once you have this, all you need to do is start training and understand the simple observations of EPOC. The information you get from the system gives you the tools to quantify the training load but also ask the questions about how to modify training to improve overall capacity and performance. The human body is always in flux: it is always adapting to load, so the body is not the same day in and day out and FB is one of the best systems to quantify these changes and better define these different states of readiness.”

Over-The-Hill Gang

One group Galanes believes benefits the most from HRV monitoring is masters athletes. “Recovery profiles for masters athletes are very, very different than young, elite athletes. As we age, there is a whole different training process that needs to occur. Ned Overend, Joe Friel and others are making some good observations on this. Since we all age differently, FB is one of the best possible tools to assess each individuals response in training and recovery. The real value at looking at EPOC is to help you understand if you’re getting the desired effect of your training. If you go too hard, you are compromising something later in the training process. It really helps clarify the focus and the implications of the training. It is the most incredible training tool that has come along in my training and coaching lifetime.”

Optimal Usage

As a frequent traveler to both Europe and high elevation (sleeping at 7,200 feet, training between 6,700-10,400 feet), being able to measure the “stress” and overall physiological impact of traveling to and training at these sites have proven to be incredibly valuable. Sure, any idiot knows that they’re tired when they get off the plane after a nine-hour flight, but what does this really mean in terms of training? Should you even train right off the plane or take a nap instead? If you do go, how long and hard should you go? Firstbeat can help answer all of those questions. And that’s just the tip of the iceberg.

Anyone who knows me knows that I lead a very unusual life. I spend more time on airplanes than many people do in bed. I have a large animal rescue and much to the amusement of my vet and farrier, I often ride my mountain bike to my farm to administer vaccines to the animals while wearing a full cycling kit (apparently this isn’t all that common). I also regularly work on three continents, ski home from work in the dark and a bunch of other stuff too strange to print, so I think most would agree that I am clearly an outlier on the curve in many ways and in many things. Now, having said that, while my stressors may be different from yours, my guess is that each and every reader out there has lots of other demands for their time outside of training and lots of factors that impede recovery, some unique to them, others not. Sure, most of these stressors most likely don’t involve giving vaccines to donkeys or having the entire U.S. Ski Team’s jump skis lost in Japan, but I have yet to meet the person who claims their job is easy, who gets all of the sleep that they’d like and who does not have any worries or responsibilities. So just how much is your stupid job, long commute or inability to attract a member of the opposite sex affecting your training? More than you might expect.

Sure, most of these stressors most likely don’t involve giving vaccines to donkeys or having the entire U.S. Ski Team’s jump skis lost in Japan, but I have yet to meet the person who claims their job is easy, who gets all of the sleep that they’d like and who does not have any worries or responsibilities.

“The thing that the most interesting about it is that it provides hard data on feedback that helps us modify our behaviors in ways that are otherwise difficult,” claimed Caldwell. “I first started using Firstbeat when I was traveling in Europe. I found that I was getting high EPOC scores on runs that I thought were easy. As soon as I recognized the stress from the long travel and adapted my training, I got better EPOC scores and felt an immediate fitness bounce. Don’t get me wrong, it took me years to learn this lesson and I had to learn it the hard way. Generally us old dudes go out and hammer. Most masters skiers train like they’re going to win World Cups. That’s just wrong. We’re exercising our fantasies, not reality. This system helps stop that and allows you to train smart. It can both slow you down and speed you up, which is an important mix. Generally our instincts don’t always line up with the true need of the situation and figuring out how to keep this in check is very, very important.”

U.S. Ski Team member Noah Hoffman with his Suunto Ambit heart rate monitor, compatible with Firstbeat technology.

One of the elite athletes that Caldwell coaches on the U.S. Ski Team is Noah Hoffman. Hoffman’s perspective is interesting in that he is exclusively focused on outcomes, not on any of the theory or science behind the system.

“I don’t really look at the numbers; I rely on Zach for that. All I know is that it helps me a great deal,” Hoffman said during an in-person interview. “I’ve been using the system for a while and I love it. It gives me piece of mind when I’m going into a big training block that I can handle the training load. I know I’m not going to drive myself to oblivion. It’s also very valuable if you start to feel rundown from travel or illness, as it gives you good feedback on just how much you should back off or push through.”

Another elite skier to use the system is Sophie Caldwell, winner of a World Cup this year. “I’ve only been using it for about a year, but I love it,” she said on the phone. “When I see my recovery trending downward, I can catch it early, which is so key. It’s also been very interesting to see which workouts take more out of me. I’ve noticed things like if I’m in Level 1, I can go forever, but as soon as I start going into Level 2, there is a much bigger cost there. I know this is very different for different people, so this allows both the athletes and the coaches to see that different workouts affect different people in different ways. Liz Stephen [U.S. Ski Team teammate) and I are both coached my Matt [Whitcomb] and we’re amazed when we compare data on how different workouts effect us. I find this fascinating and it clearly shows how important individualized monitoring is for athletes. If Liz and I were attempting to follow the same program, it wouldn’t work well for either of us. So thanks to the data and insight we’ve gotten from the system, we’ve all learned a lot about ourselves and training.”

Without a doubt the most ringing endorsement came from Tad Elliott, who had a history of illness and overtraining. “Firstbeat saved my career. I was so sick and struggling so much with how to carefully and gradually return to full activity, I never could have made the comeback that I did without Firstbeat. It is that important to me. Now, my case may be a bit extreme, but it is most certainly very useful for all endurance athletes, in particular busy ones.”

Weaknesses

Is this system perfect? Of course not. Firstly, to achieve nighttime recovery data, here’s a shocker, you have to wear something when you sleep. Firstbeat gives you two options: your traditional HR monitor chest strap or specially dedicated chest sensors.

The HR monitor chest strap is easier, cheaper and I suppose looks less weird (though a word to the wise: prepare yourself for lots of comments/questions from your significant other). The disadvantage is that this setup is more prone to error. The chest sensor option is very, very accurate, but not only do you have to buy electrode patches (cheap, but a PITA to remember to bring on trips and re-order) you also look like you are undergoing screening for the Mercury space program every night as you prepare for bed. The system provides uber-accurate measurements, but sadly I found it to also be a bit wonky. If you do not upload the data every few days, you experience the dreaded “system crash and freeze” therein losing all of your data. This is not an issue if you stay on top of your uploads, but it seems as though this should work better for a system of its price. Sleeping with either contraption is a bit of an adjustment, but thankfully FBD is a good sleeper and after a few nights I don’t even notice either option. Your mileage may vary.

Several high-level skiers show off their Suunto Ambit heart rate monitors:(clockwise, from upper left) Italian nordic combined skier Samuel Costa, Steamboat Springs Winter Sports club alumn and current CU skier Lucy Newman, Swiss nordic combined skier Tim Hug, and 2014 Olympic silver medalist Akito Watabe of Japan. (All photos: FBD)

The system requirements claim that it can work with several different heart rate monitors, but everyone I’ve spoken to uses a Suunto Ambit 2 or 3, myself included. I found the Suunto to be superior to the Garmin even as a stand-alone HR monitor, so using it for FB was an easy transition. And I’m not alone — look on the wrists of many a World Cup skier and you’ll see a Suunto, so I don’t view this as a negative, but knowing that you may need to also buy a new watch is an important consideration for budget and ROI. Then there’s the issue of the software not running on Mac. This can easily be overcome by installing an emulator, but again, it seems like software of this price should be Mac compatible.

On a more macro level, “power user” (see what I did there?) Zach Caldwell offered a few more criticisms, “Overall the software could be a bit more user friendly. There is a lot going on, which is a good thing, but this means that it can take some time to understand how to correctly interpret the data. Perhaps more importantly, it is a speedometer. It tells you how fast you’re going. It does not tell you how fast you should be going. This is not a weakness, but rather a common misperception of the utility of the device. It is a fantastic device, but all users and potential users need to be aware of what is actual does and does not do.”

Galanes seconded this observation, “People make the mistake of buying the software, installing it, going for a run, then looking for something magical. It doesn’t work that way. You need to establish a baseline for recovery, do some VO2 tests and begin to look for trends. It takes a few weeks before the data will start to be meaningful and you need to understand how to properly interpret it, but once you have all of that down, it’s the best thing out there by a long shot. If you can work with a qualified coach who has experience with the system, that’s the best of both worlds.”

“People make the mistake of buying the software, installing it, going for a run, then looking for something magical. It doesn’t work that way. You need to establish a baseline for recovery, do some VO2 tests and begin to look for trends…” — Jim Galanes, Olympian, former U.S. Ski Team coach and current Firstbeat rep, on Firstbeat system

Flora also believes that metrics such as heart rate, lactate, etc., need to taken in context and used as a part of the “big picture”. “HRV can help athletes see trends and match up with what they’re feeling, which is very important, but using it as a main driver can be complicated,” he said. “I am a big believer in athletes learning how to understand what’s happening with them.”

Biggest Takeaways

“I’ve been around sport for a long time,” said Caldwell, “first as an athlete and then as a coach and one of the biggest things that I see while advising my athletes is just how hard it is to coach yourself. I include myself in this, too: my personal instincts for training are terrible. Every basic instinct I have is to run myself into the ground. I always thought I just wasn’t tough enough, but in reality the problem was that I was way too impatient and way too stupid. I wanted to go faster right away and I didn’t want to listen to my body. I know this is not just me either, so being able to quantify some of these issues helps me have a good discussion with athletes in a very non-threatening way, which is important.”

“One of the biggest things that I’ve learned is just how right coaches are,” Hoffman said. “As athletes we always hear about the importance of rest and recovery, but we you can look at the data right on the screen about how your behavior impacted your ability to train, that is much more powerful than anything a coach can say.”

Fellow U.S. Ski Team member Sophie Caldwell agreed, “I’ve become a lot more aware of my recovery and the impact that different workouts has on recovery. It makes me think a lot more about how important recovery is for success. It’s forced me to pay more attention to all of the other parts in my day and that’s a good thing, a very good thing. I’ve been using it for almost a year, and while I’m not at the point where I rely on it 100 percent, it is very helpful to see my trends. Sometimes it shows that I’m getting into a bit of a hole and this helps me stay in front of it. I also use it to ramp things up if it looks like I can handle more load. I can probably do a pretty good job guessing, but I certainly would have missed it a few times and it is in those instances that it is particularly helpful. My overall experience is very positive.”

Hoffman continued, “One of the first things that I did when I started using the system was I collected data for 24 hours/day for 6 weeks. What we learned with this is that my activity through the day correlated much more highly than I believe earlier to my nighttime recovery scores. Some of the coaches had told me that they thought I was being too active in between training sessions and that’s exactly what we found. It was also surprising the types of things that disrupted recovery. I’m a competitive guy and it turns out that even board games elevate my stress levels enough to impede recovery. I never would have guessed this. It’s also important to note that while we have prioritized recovery in our use of the system, I definitely do use it for training and racing, in particular for things like pacing. It helps you verify what you think you already know in terms of feel. I look at it as a great safety net.”

Applicability for Age-Groupers

So is this just a tool for the over-80 VO2 crowd with Olympic aspirations? Hardly. In fact, given the complexity of training for any race while working full time, this system is probably even more applicable to age-group athletes. “It’s probably more important that people who aren’t full-time athletes use this system,” noted Hoffman. “It’s WAY harder to balance your training load that manages your energy appropriately, as non-professional skiers have so many other distractions. I can at least try to devote most of my energy to training, so it’s easier to recover and not overdo it, but for people who have lots going on, it would be incredibly valuable. It is an important guide to help you train effectively with everything else that you have to do.”

Zach Caldwell agreed: “If you use a system like Firstbeat to measure stress load external to exercise output, you’re nailing things down from both sides. Neurological state and physiological cost and that’s a great thing. Human performances lives in the gap between input and output. If you’re only quantifying one or the other, you’re opening yourself up for surprises on race day, I don’t care what sport you’re in.”

Parting shots

In this day and age of the “shallow reader,” this article was long, perhaps too long for the taste of many, but there’s a lot going on here and I felt it was important to accurately describe the power and limitations of this very exciting technology from multiple perspectives. How you proceed from here is up to you, but to help perhaps guide some of your next steps, I asked some of the people the most familiar with the system for their advice to those considering taking the plunge.

“Jump in with patience,” advised Zach Caldwell. “Definitely do it, but go in with realistic expectations. The system won’t pay dividends in the first week, but if you are patient for three months, you absolutely will not be disappointed. But you need to be committed: three months of wearing this thing to bed. Training with it every day. Doing baseline and follow-up testing. Learning how to interpret the results. But if you are consistent and patient, you will learn a lot. It is an incredibly valuable tool when used correctly.”

Galanes went one step further, “Balancing endurance and intensity training is not easy and finding that line without the insight that the system provides in very, very difficult. FB gives you access to much better data and a much bigger picture. It is going to change your paradigm on what is optimal training and it is going to change how you view endurance training, all in a very positive way, but you need to be sure you are using the system correctly. If you do, you will feel better and you will perform better.”

Elliott added, “If you’re juggling work, family, illness or any other stressor, I strongly encourage everyone to use it. I never could have made it back to the top level with the data I got from the system and I know it will help most, if not all athletes.”

“I’ve had a very positive experiences with it,” said Sophie Caldwell, “so I absolutely advise people to use it, but start out cautiously. Track your training and sleep, but don’t rely 100 percent on this system. You need a baseline, but the more time you spend with it, the more you learn to correlate how you feel with what the data is showing, which makes you even more comfortable with it and able to count it on even more. It’s not the only tool that I use, but I sure am glad that I have it.”

Hoffman summarized the whole process nicely and offered solid advice, “Take it slow at first. Firstbeat tells you a lot, so it can be a bit overwhelming. Take your time, learn what the numbers mean or find someone who does and be patient. It takes a while to understand how this is all relevant to you, so don’t get overwhelmed by it. Stick with it, though, and you’ll be glad that you did. You will learn a lot and you’ll be a better, happier athlete.”

For more information on Firstbeat technologies and pricing information, visit Firstbeat.com.

August 8, 2016