How Knowledge from a Little Wrist Strap Can Change Your Life

The job description for the U.S. Navy’s Explosive Ordnance Disposal (EOD) technicians includes tasks such as “detonate and demolish hazardous munitions, pyrotechnics, and outdated explosives” and “perform parachute or helicopter insertion operations.” It’s like The Hurt Locker, only sometimes they have to deactivate mines underwater, too. But what if there was a tool EOD technicians could use to help minimize stress and increase technical proficiency, which, in their line of work, could literally mean the difference between life and death? Enter WHOOP, the 24/7 heart rate and performance monitor.

WHOOP is a sleek, wrist-worn device that tracks personalized metrics every day including recovery, strain, and sleep and is used by some of the best athletes in the world. In efforts to help EOD technicians better prepare for and manage their critical jobs, WHOOP sent 40 of its devices to a team as part of a data study. 

Over the course of the six-month study, 20 of the EOD participants got to see their data in real time, while the 20 in the control group did not. The results were staggering: on average, the bomb defusers who were able to adjust their behaviors and routines based on their WHOOP analytics increased their nightly sleep by 45 minutes, dropped their resting heart rates by five beats per minute, and increased their all-important heart rate variability by six milliseconds. Not surprisingly, when it came time to take the Physical Readiness Test, the technicians who had a handle on their baselines performed 17 percent better. In other words, WHOOP helped the EOD technicians train and conduct themselves at a higher level.

Participants in the EOD study found that they got more sleep, lowered their resting heart rate, and increased their heart rate variability when using WHOOP.

But here’s the thing: you don’t have to defuse bombs for a living to reap the benefits of knowing your baselines. WHOOP helps elite athletes train and perform more strategically; keeps emergency health workers fresh; allows pregnant women to gauge their progress throughout gestation; and has even been credited with saving a life (a 33-year-old WHOOP user’s suddenly erratic data convinced him to go to the hospital, where his doctors identified his heart attack). More recently, pro golfer Nick Watney actually deduced that he might be COVID positive because his WHOOP band detected a change in his respiratory rate. A test confirmed his suspicions and Watney was able to quickly protect those around him. 

The spike in Nick Watney's respiratory rate that led to him getting tested for COVID-19.The spike in Nick Watney’s respiratory rate that led to him getting tested for COVID-19.

The reason WHOOP has helped such a diverse cross section of people unlock their potential is simple: everyone has the ability to improve performance and quality of life; WHOOP just provides you with the data and the tools to uncover the secrets your body is trying to tell you.  This is true whether you’re a masters-class athlete with a day job and a family or a frontline health care worker trying to perform your best. To excel, we need to balance our physical and mental stressors with the right amount of sleep, rest, and recovery.

Past attempts to achieve such balance haven’t really cut it. While athletics and the military have long known the importance of recovery for performance, even in those fields it’s largely been a guessing game as to when we need to rest and when we can charge. Outside of a lab, the data just wasn’t available. As for day-to-day life, we just dealt with the fallout of not knowing if we were out of balance. 

That’s the idea behind WHOOP. Much more than a fitness tracker, WHOOP is a subscription service that gives you access not only to raw data but to complex and personalized analysis that, in essence, lets you take better care of yourself between workouts and life’s stressors. 

The WHOOP recovery algorithm does all this by tracking four key baseline metrics—resting heart rate, heart rate variability, sleep, and respiratory rate—that are constantly fluctuating in response to factors like stress, alcohol, caffeine, exercise, and diet. And because it records all that data 24/7, it provides you a full physiological profile of each day, allowing you to assess your body’s needs and suggesting potential behavioral changes.

Brooke Wells uses her sleep data to help determine how hard to push herself in training the next day.Brooke Wells uses her sleep data to help determine how hard to push herself in training the next day.

It’s complicated stuff, but the genius behind WHOOP’s strap-and-app combo is that it strips away all the noise and makes it incredibly easy to monitor—and then assess and react to—your baseline metrics. The band itself is low-profile, comfortable, and intentionally simple, with no watch face to distract you with notifications. It doesn’t count steps, which are irrelevant to your physiological performance and overall health, or track distances (though the WHOOP app can do that).

Here’s the easiest way to think about it: your WHOOP essentially acts as an accountability coach (in fact, the app includes both a sleep coach and a strain coach feature), showing you where your strengths lie and where you can improve—like tweaking how much sleep you get or skipping a workout at a certain juncture. The data becomes even more interesting—and instructive—over time. Because your baseline is constantly evolving, when worn over a period of months, your WHOOP can provide a snapshot of your overall health, so you can see how things like alcohol affect your sleep quality or how a series of tough workouts has left you depleted.

The Strain and Sleep coaches make recommendations for what your daily goals should be, and how to adjust to meet those goals.The Strain and Sleep coaches make recommendations for what your daily goals should be, and how to adjust to meet those goals.

While nearly everyone would benefit from having a wrist-mounted accountability coach, athletes of all stripes, from new runners to elite cyclists, have the most to gain from paying close attention to their baseline metrics. The reason for this, too, is simple: instead of downloading, say, a 5K training plan from the internet and then following the weekly schedule as best you can based on how you “feel,” or blindly doing what your coach tells you to do on a particular day, wearing a WHOOP allows you to train smarter by reacting to your actual physiological state in real time. 

The key metric here is the aforementioned heart rate variability, or HRV, and WHOOP’s ability to calculate it sets it apart from other wearable fitness trackers. Research has shown that HRV is one of the best objective measures of fitness and can be used as an indication of physiological readiness, including your recovery status, ability to tolerate physical stress, and your risk of injury, fatigue, and overtraining. 

HRV is a complicated field of study, and training, lifestyle, and biological factors can all affect it. But it can best be thought of as an overall indicator of the heart’s and nervous system’s ability to readily toggle between action and rest. HRV is the variance in time between successive beats; your WHOOP captures it during the last episode of your slow-wave sleep each night. The higher your HRV, the more variation your heart rate is comfortably capable of, which is a natural indication of your body’s readiness to perform. And by monitoring the variability of the rhythm, WHOOP can actually tell you when you should go for that PR—or grab some couch time instead.

On the day she won the 2018 mountain bike world championships, Kate Courtney had her highest HRV ever and a WHOOP recovery of 96%.On the day she won the 2018 mountain bike world championships, Kate Courtney had her highest HRV ever and a WHOOP recovery of 96%.

Your standard heart-rate monitor or fitness tracker doesn’t calculate HRV, but the WHOOP strap does. The added insight this metric provides is why everyone from the Navy to EF Pro Cycling, which took fourth place at the Tour de France last year, is partnering with WHOOP and why its diverse list of athletes includes NFL players (Patrick Mahomes), surfers (John John Florence), and mountain bikers (Kate Courtney). It’s also why, earlier this fall, we (Outside) collaborated with WHOOP on Project PR, a first-of-its-kind running experiment and 5K training program designed to uncover ways to optimize training based on actionable recovery data provided by WHOOP.

We signed up thousands of participants in two groups—one wearing WHOOPs for the duration of the eight-week 5K training program, and one control group without WHOOPs—with the goal of revealing how everything they do, from how much sleep they get to what they’re eating and drinking, can affect running performance. (We’ll have results to share later this year.) As Kristen Holmes, WHOOP’s VP of performance science and a former collegiate athlete and coach, likes to remind people, “Your competitive advantage is in your downtime, and if you’re not measuring the impact of your downtime, you’re simply missing a massive piece of the performance puzzle.” Or you can think about it this way: your body has all sorts of ways of telling you how it’s performing. A WHOOP gives you a more holistic, accurate, and granular way of understanding how it’s performing.

Join WHOOP and get the WHOOP Strap 3.0 free with membership.


WHOOP uniquely blends hardware, software, and industry-leading accurate measurements to help people sharpen the edges of fitness and performance, create impactful behavior change, and empower them to optimize all facets of life. The WHOOP membership includes a free WHOOP Strap 3.0 for 24/7 actionable insights and health coaching.

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