Many teams and athletes have all kinds of ways to assess recovery, from strap-on heart rate monitors to assessing acute power through vertical jumps to more advanced testing prevalent in professional sports. However, none of these are particularly accessible to an individual training on their own or for trainers working with individuals in a private-sector setting, especially if it’s an online coaching setting where you’re not physically present for the workouts.
Yet, there is one piece of technology that’s increasingly popular and accessible to everybody: wearable technology. With wearable technology—or “wearables,” as the cool kids call them—any individual can get critical info such as heart rate data, sleep statistics, and more right on their smartphone, easily and in a noninvasive manner. The most popular wearable technology brands include Fitbit, the WHOOP Strap, and Oura, and you could even throw the Apple Watch into the conversation. Whichever device you choose, look for two important features:
- It should provide 24/7 monitoring and be made to be worn day and night. If you don’t wear it at night, for example, you’ll miss key sleep and heart rate data.
- It is only a tracking device. By staying focused on the data, the device commits all its memory and resources to data tracking and management. For instance, you wouldn’t want to find out your brain surgeon spends most of their time working their second job as a librarian. (Not that there’s anything wrong with that, I just wouldn’t want them as my brain surgeon.)
With this in mind, the WHOOP Strap, Oura Ring, and higher-end Fitbit models check both boxes. I’ll save the more nuanced differences between them for another article.
While wearables have their drawbacks, they democratize the data once previously held by high-level coaches. And with that data, everybody from elite athletes to everyday gym-goers can get insights into their health and performance previously reserved for the best of the best. If you’re training in a team setting but don’t have the resources to provide, for example, a set of Polar heart rate monitors to everyone, you may find that a majority of athletes already collect heart rate data with their personal wearable.
However, most of your athletes won’t really know how to use the data to make changes. They’ll get their fancy new wearable watch but then ignore everything it tells them. I don’t believe this is a fault of the individual’s willpower; rather, it’s that they don’t know what they’re looking at. And more importantly, even if they did know what HRV and REM sleep were, for example, they wouldn’t know what to do about them.
Once you teach your athletes what the most common metrics on their wearable device mean, they can then use that information to manage their workload, enhance recovery, and ultimately improve performance. Plus, you give them the skill set to do this on their own, independent of the team setting.
If you’re in a private one-on-one setting, you can take this even further, using the wearable data as an integral part of managing their training, recovery, and overall health.
And, of all the metrics present on wearable devices today, I don’t think there are any that are more misunderstood than heart rate variability, or HRV. HRV has become one of those fancy acronyms synonymous with data, tracking, and high performance. But the problem with it, and a problem with a lot in our field, is how to take a valuable tool like HRV and communicate it in a simple way for our clients and athletes to understand it. What is HRV? What does it mean for our clients?
HRV is a measure of how much your heart rate varies (hence, the name heart rate variability).
For a general understanding of HRV, including exactly what it is and where it comes from, refresh your memory here. But the HRV derived from a wearable device is slightly different from the HRV you collect at any given time of day. If you collect HRV during your athletes’ workouts, that’s not what I’m talking about here.
When Does the Wearable Assess HRV?
Obviously, heart rate and HRV depend on the athlete’s activity. If you’re working out and all of a sudden do a sprint, your heart rate will shoot up, thus affecting the HRV score. These HRV scores are not what the most common wearable devices measure, and they have separate meanings and applications. The HRV that shows on a wearable device is taken while you’re sleeping. The HRV taken during sleep shows general signs of readiness and recovery for the day, rather than assessing a particular moment. Waking HRV has different meanings and applications, but that’s not what a wearable device refers to when reading an HRV score for the day.
What Do Wearable HRV Scores Mean?
For the first several days (or even weeks) of looking at an athlete’s HRV data pulled from their wearable device, you’ll start to see a general pattern and reasonably assume what their “baseline” HRV score is. Of course, the more baseline data you have—like the control for any experiment—the more reliable it will be. When working with someone, they’ll often have had a wearable for some time and will have weeks of HRV data piled up that you can look at and make sense of.
In any case, after an athlete has established what their HRV hangs around when they’re well recovered, you can then be on the lookout for variations away from normal. The higher the HRV score, the better recovered and more prepared for stress an athlete is.
Why a Higher HRV Score on Your Wearable Signifies Better Recovery (and Vice Versa)
When our parasympathetic nervous system is more dominant, our heart rate at rest (like sleep, when the wearables pulls HRV data) will be lower. Then, when your heart rate increases because of increased oxygen demands, the rise will be greater, and you’ll have an overall higher HRV. A higher HRV signals that the parasympathetic branch is more dominant and you’re well-recovered.
There are exceptions to this, as this article aptly articulates. But for the vast majority of people, the exceptions only matter after they first learn the general trends. And for most trainees, understanding that in most instances a higher HRV corresponds to enhanced readiness, and vice versa, is a simple benchmark and framework they can use to take action on.
How to Take Action on Changes in HRV
The HRV score on a wearable device will change due to a number of factors. If over the last 3-4 days your HRV has kept creeping down, that’s an indicator that your sympathetic nervous system is overpowering, and you’re not recovering optimally. And, of course, that could be a result (and likely a combination of) a number of factors: Your immune system could be under attack, you could be not sleeping well, you could be dehydrated, or maybe you just added a new stimulus to your training.
Often, the first factor you’ll want to look at with your athletes is their workouts. Have you increased the volume or intensity? This, of course, could explain the decrease in HRV. If you respond to these obvious changes in stress by focusing on recovery methods or otherwise aiming to lower stress, you will soothe HRV back into the normal range.
However, sometimes HRV will decrease, and you won’t have an easy answer for the cause of the increased stress. This is where I’ve seen the best value from looking at wearable HRV data. You have to work with the athlete to try to identify where the stress is coming from. Is their sleep wildly off? Are they stressed with work or school and need changes made to their workout program because of it?
This most often leads to a deeper conversation beyond training, and into deeper facets of the athlete’s lifestyle—and even their life. As trainers and coaches, we’re often with our athletes for a few hours per day, max. The HRV data can give us an insight into supporting them during the other hours of the day.
Additionally, HRV fluctuates from day to day, but maybe not so much that it causes concern and warrants a deeper conversation. But I encourage the clients I work with to respond to even slight changes. If their HRV is above normal, even slightly, I encourage them to throw in an extra set to take advantage of the fact that their body is well recovered and prepared, and vice versa.
What Makes Looking at HRV on Your Wearable So Valuable
Even when you can’t detect changes in your stress and recovery, the autonomic nervous system can, and one of the clearest ways that’s reflected is in HRV. In other words, HRV is a very “touchy” metric. It’s sensitive, in the best way possible.
For example, before you get sick, your HRV might take a noticeable hit. Your immune system is under attack, and that adds stress that will ultimately show up in your HRV. When you encourage athletes to look at and “listen” to their HRV score, they can halt or blunt the effects of that sickness by prioritizing recovery when they see their HRV drop on their wearable.
This, in a nutshell, is what makes HRV so powerful. It gives a deeper look into the body’s stress and recovery beyond what we can physically feel. It’s like getting to talk to the unconscious part of your brain: the autonomic nervous system. That’s right, it’s giving consciousness… to unconsciousness. Give it a minute; it’ll make sense.
Training Factors: Using HRV to Measure Adaptation
When you increase a number with training factors, from volume and intensity to adding a new kind of stimulus, you can expect your athletes’ HRV to dip. Then, after some time, they will adapt to it, and their HRV will come back up. Knowing this, you can also use your HRV score to assess how, or how quickly, your body is adapting to a new stimulus. If, for example, you have your client go from training three days per week to four, you can see how that affects their HRV and how long it takes to return to baseline. Once they’re at the baseline, you can then add another new training stimulus to keep challenging the body and make continual progress.
But you also have to consider that HRV might be affected by other factors. You may have to look at nutrition, hydration, sleep, stress, or other health conditions that could impact your athlete’s HRV.
The number of factors might be overwhelming. But it should also be empowering. If you see HRV go down, that doesn’t mean the athlete’s sleep is messed up or the training volume is too high, necessarily. Rather, HRV is made up of a multitude of factors that all form the puzzle that is your health and performance.
We can’t begin to improve that puzzle—to tweak one of these factors here or there for the better—without being aware that adjustments need to be made. The moment we’re aware of what’s going on is the moment we can take control and make the necessary changes.
How Do I Manage My Athletes’ HRV?
The tendency here may be to ask, “How can I improve my athletes’ HRV?” But we don’t necessarily want the HRV number to stay high. In fact, training should and will cause a downward bump in your HRV. But having the data can help you add in the right amount of stimulus and gauge how it affects your autonomic nervous system. You can add just enough new training to spur stress and ultimately adaptation, but not so much that it causes a setback. This is where a knowledge of HRV provides key insights into training.
However, if you haven’t added stress to a training program, but your HRV decreases, that’s the time to look at other factors like lifestyle factors to assess what could be signaling a sympathetic response in your autonomic nervous system. Check the simple boxes first, like hydration and sleep. See if those bring your HRV back to baseline and go from there.
One common element I’ve noticed among high performers is that their sleep hygiene is off. Sure, they lie in bed for eight hours, but the room is too hot or too bright, or they work out too late at night, and that disrupts their sleep and, ultimately, their recovery.
Second, just make sure they’re adequately hydrated. It’s one of the common factors, and it’s so easy to fix. Encourage them to start drinking more water and see what effect that has on HRV.
As you work with your athletes on making changes in response to their HRV, over time you’ll empower them to make changes on their own. Sure, you’ll still work with them to manage their workload and recovery, but you’ll also give them the knowledge to manage their lifestyle on their own. Understanding HRV gives them the awareness to understand theirbody better; to become more in tune with its subconscious messages and adjustments.
What Happens When You Use the Wearable Data and Make a Change? Make Another Change.
When you add stress in, at first it will have a negative effect on HRV. The body will have to start working harder to recover. But then HRV will go back up, and it will hit the inflection point where it was before the new stimulus. That inflection point begins the super-compensation phase. This phase is what allows athletes to take on that stress again, in a different way. If we put the same stimulus on their body after compensating, the dip in their HRV won’t be as low. And then maybe next time it’ll have an even smaller effect on HRV, and eventually it won’t affect HRV at all.
That HRV score now tells us that we need to do something again to change the stimulus. This is how we progress, and how we get better, and how we can use HRV as a guide from a fitness standpoint.
Now that you know what HRV is, what factors affect it, what to be aware of, and what applications you can make, you can use it to actually improve the health and performance of your athletes.