In the last decade heart rate variability or HRV has become the gold standard in measuring recovery and readiness in the human performance industry. Once available to only those at the tip of the spear in human performance this biomarker is now a near ubiquitous feature on active sport watches not to mention wearables whose design is wrapped around HRV as a primary feature.
The purpose of this article is neither to debate nor reinforce the efficacy of HRV as a marker for recovery. That requires more words than we have space for here. What we will set out to do is help those of you who are already using a device to track HRV bring more practical understanding of this information as well as enhanced clarity to the data that you are getting.
Heavenly Bank Account
Wearable brands like to compete to persuade you who is better at telling you when to train hard and when to lounge in the hammock. Regardless of the validity of their particular algorithm it's important to understand a fundamental fact - no wearable can tell you when it's appropriate to exercise any more than a bank statement can tell you when to spend money. All they do is deliver information regarding how much money is in the account. You have to decide whether the next expense is worth it or not. The same goes for HRV.
HRV can be easily understood like managing a bank account. Stressors are like withdrawals from the body and recovery is like deposits. When you track your monthly budget you'll notice there are withdrawals and there are expenses. Similarly, there are lots of sources of life withdrawals and these withdrawals vary in magnitude, duration, and context just like financial expenses. Not only do exercise, training, and sports make withdrawals, so do emotional and psychological stressors that are a normal part of life.
Some withdrawals are obviously appropriate when we look at the balance sheet. For example, one of the largest expenses for most of us is our monthly car payment. When that $500-$700 nut gets cracked every month you don't have a coronary over the bank statement do you? Probably not. You expected it. The money that was in the account was spent. Similarly, when there's a decline in HRV the question should be: Do I understand why this happened?
On the other hand, some expenses are insidious little things that nickel and dime our energy away. Small psycho-emotional gremlins can be like that newsletter subscription that your forgot about from two years ago. It started out as $1.99 a month and over the last twenty four months it progressively rose to $19.99 with add-ons and suddenly you're not sure how you paid two grand to Historical Bicycles Monthly last year. I think you get the point.
What's Going On?
A couple of years ago I had an executive client who was using a WHOOP to track HRV. This individual was incredibly fastidious. Nutrition, sleep, stress management were all battened up tighter than hurricane shutters. But a short time into our experiment he called me and reported that every Wednesday his WHOOP was reporting a severe dip in his HRV. Monday and Tuesday would be relatively stable and then boom, the bottom would fall out. His initial reports of stress and recovery revealed no obvious cause for the dip. After a bit more thought however, one thing occurred to me. We worked the hell out of his lower body on Tuesdays. Our Tuesday afternoon workout including multiple rounds of deadlifts at 85 percent or so of his maximal effort followed by lower body hypertrophy exercises. By any account, a very intense stimulus (aka stress). As it turns out the dip in his HRV wasn't because he was doing anything wrong per se, it was a reflection of the hard work performed the day prior.
When our HRV scores go down it's not necessarily a problem. It means there was a stressor or an accumulation of stressors that taxed the system. What matters is if there was also a predictable return to normal (or better )in a reasonable amount of time. In this particular case the answer was yes. Sounds like a healthy athlete to me. It's easy to get locked into the idea that higher HRV (recovered) is good while low HRV (stressed) is bad. That kind of binary thinking will undermine the real goal of tracking it in the first place - to better understand how your physiology responds to stress over time. Rather, think about why your system might be stressed and if that seems to be an appropriate response to the stress that it's undergone? Furthermore, how can you use this information to better manage the money in your account? Can you make more deposits? How about limit withdrawals? Ultimately you have to be the one who balances the budget.
Clock of the Heart
Another place we can get stuck with markers like HRV is in the comparison of our score to the ideal set in place by the manufacturer. While it's good to have an idea of what ideal ranges might look like it's often far more useful to pay attention to how our own information trends over time. In the grand biological scheme of things even a month of data is a snapshot in the cycle of life of stressors, our response to them, and the context in which they take place.
Trends offer patterns in sets of data over long periods of time. One of the best things I've done for insight into my own sleep and recovery was wearing an Oūra ring all day, every day, for an entire year. Not only could I learn about trends in my habits related to my physical fitness outputs I discovered that there were sort of "meta trends" that showed up because of changes in the environment due to the time of year. The most potent lesson that comes to mind is the realization that in the summer I tend to trend to reduced HRV and recovery from strength training.
At first I thought I was doing something wrong and that I needed to reevaluate my entire training regime. Then I realized something that made a light bulb go off. Virginia Beach summers are very hot and humid and it stays light out quite late as well. These two factors combined led to me staying up later to go for walks and hang out with my wife. Well, my four dogs could care less about my bed time. They're up at the first chirp of the birds to get breakfast. These factors combined led to an average of 65 minutes less sleep in the summer. I certainly could have changed my sleep routine to prioritize my gains but that time with my wife is important so instead I altered my training plan slightly (as well as my expectations). Now I reserve the colder, darker months of the year when I sleep 8.5-9 hours a night for really going after improvements in strength and use the summer for more outdoor activities and strength maintenance.
Back In Black
Regardless of the specific device we use to measure HRV or any other recovery metric it's important that we understand the role it plays in our overall performance plan. The information we get is just that, information. It's up to us to keep that information in context and ask good questions so that the tail doesn't wag the dog. If your savings account is low because you just put a down payment on a new home that's no reason to go all Daffy Duck about money. Your balance sheet makes sense because you chose to spend that money on a worthwhile investment. Knowing your spending habits over time helps you continue to make good choices moving forward. HRV is not a tool to rule you. It is simply a way to help you keep your biology in the black.
Thanks for reading,
Rob
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HRV tools I’ve used:
Oūra - My current go to.
WHOOP - Popular and convenient.
OmegaWave - The industry standard.
ADDITION (01/27/2025): Morpheus - The brainchild of MMA conditioning guru Joel Jamieson.
There are others. Some good, some not so good. These are the ones I’ve used most.
If you’ve used different devices that have worked (or not) put them in the comments below.
Thanks, Paul.
Rob,
You might take a look at “hurricane shutters,” not “shudders.”
It’s in the “What’s Going On” section.
Thanks for this article.