While technological advancements are often a reason for ethical dilemmas and debates, I’m a firm believer that they also have the potential and the power to help us make better decisions. 2020 has emphasized the importance of preventative care and immunity management during widespread COVID-19 concerns. Science is urging us that healthy living starts with sufficient sleep, optimal nutrition, and balanced exercise. Peter Drucker once said: “You can’t manage what you can’t measure.” But what holistic measures do we have and how should we track the quality of our sleep, recovery, and activity?
What is WHOOP?
WHOOP is a fitness tracking wrist strap that works with a companion mobile app to provide unique health insights. While there are many reasons to love this device, what’s most interesting is the technology behind it. WHOOP wrist strap collects an enormous amount of data through its sensors that are sending signals 100 times per second. All of this data allows WHOOP to create personalized insights and recommendations based on your strain, sleep, and recovery. The algorithm powering WHOOP is state- of-the-art technology that uses cardiology and physiology to create a systematic approach to understanding our bodies. WHOOP collects unbelievably valuable correlations between physiology and performance, offering a new approach to health monitoring and the different ways to interpret or act on your body’s feedback.
Even though I have been working in the fitness space and continue to keep an eye on the market and new developments, getting acquainted with WHOOP was quite a steep learning curve. I had to spend multiple evenings trying to learn and decode the terminology, the trends, and what it all means for me. So I’m hoping to synthesize some of that knowledge here for your convenience.
The Overview tab gives you general suggestions for your daily recommended (optimal) Strain, Heart Rate Variability (HRV), Your Day Strain accrued, and a projection of calories burned. The overview screen also has a timeline portion that shows when you started your day and tracks your activities. This is also the place for you to track your symptoms, events, supplements, and basically, anything that changes your context. The battery charging is very practical; you simply attach the battery onto your wrist and charge it while wearing the strap. After you’re done, feel free to plug in the battery itself until the next time you need it. You’ll have to charge it every 5 days or so.
Strain reflects your cardiovascular exertion. The higher your heart rate is and the longer your exertion lasts, the more strain your body takes on. Important to note that Activity’s strain reading is tracking how hard you worked, not necessarily what exactly you did. WHOOP has developed a scale from 0 to 21. Strain scale breakdown looks like this: 09 - 9 indicates light, 10 - 13.9 moderate, 14 - 17.9 strenuous, 18 - 21 all out strain range.
Strain activity gives you a real-time reflection of your day and your level of activity. This tab has Max Heart Rate, Average Heart Rate, and Calories burned. Your basic metabolic expenses are also taken into account, so you might wake up with 34 strain acquired already. Nothing unusual with that because even if we lay flat all day, the body is still utilizing energy. Having this information allows you to see the overall pattern of that expense.
How reliable are WHOOP’s caloric consumption and spending projections? Well, this is one of those not so black-and-white topics. Let’s start with the basics. Why is it important to track calories? If you’re trying to lose weight or build muscle, you need to know how many calories you consume and how many calories you spend in order to adjust your tactics so you can achieve your goals. Losing weight will require a caloric deficit while building muscle will require a caloric surplus. Our bodies need food to stay alive and even more of it to perform any activity. Simple in theory, not so much in practice. For calories consumed, you can either follow a meal plan put together by a professional nutritionist or trainer, or track nutritional labels on food packaging. However, these are only projections, and the caloric and nutritional value may be off by up to 20%. FDA allows for a 20 percent margin of error. Your ice cream cone might be 300 cal or 360 cal! This deviation also applies to everything else you consume throughout the day. So if you aim for 1600 caloric intake a day, you might be getting 1920 calories without knowing it! What can you do about it? Well, meal prep and cook yourself as much as possible.
Let’s dive into the tracking of your caloric expenditure. The most accurate way to calculate calories burned during exercise is through “indirect calorimetry,” which measures gas exchange (oxygen and carbon dioxide). Since indirect calorimetry requires the use of a device covering the nose and mouth, such a technology is not available in wrist-worn devices; it’s also not widely available at all. Working within the limitations of a wrist-worn device, calorie estimates using HR have been shown to far outperform those using acceleration (motion) alone.
The most commonly used heart-rate-based formula for estimating caloric expenditure during activity was developed in 2005. Despite being the best-performing published algorithm, it still has some issues:
a) It was fit only to exercise conducted at an intensity of 57%, 77%, and 90% of Max HR and therefore untested above and below these intensities.
b) It was found to explain only 73.4% of the variance in true energy expenditure.
This means that a workout estimated to consume 1000 calories could have easily burnt 734 to 1266 calories — a massive difference if you are trying to use this information to modify your body composition.
So how does WHOOP calculate the caloric expense?
WHOOP’s algorithm (which was inspired by the study mentioned above) has been modified to better model the outcome of the lowest-intensity exercises and to better integrate the active burn and Basic Metabolic Rate formulas by smoothing the transition between rest and exercise modes. This update primarily impacts periods of time in which your heart rate is between 30% and 40% of your heart rate reserve — the range from your resting heart rate 0% to your max HR 100%, which is above resting/restful activities but below the level at which people typically exercise. This update has no impact on heart rates below 30% of your heart rate reserve and minimal impact on high-intensity exercise.
Why track then?
Regardless of what any calorie tracker is advertising, estimates of caloric consumption need to be understood to be just that, estimates. However, this information can help understand the overall patterns you have in terms of calories in and calories out throughout the day. Heart-rate-based calorie estimates, like the ones provided by WHOOP, scale reliably with true caloric consumption, meaning that you can look at trends in caloric burn and trust that they are accurately identifying relatively high and low calorie-burn periods. This reliability is key to its use because it means that eating more or eating less on days when you burn more or fewer calories is still a reasonable way to action this data. I find this is an important piece of knowledge whether you’re buying WHOOP, or Oura Ring, or Fitbit. Any of the devices on the market will give you the information you’re seeking, but there is always a margin for error.
WHOOP tracks your recovery as a way to explain your body’s readiness for the day. It relies on Heart Rate Variability, Resting Heart Rate, Respiratory Rate, and Sleep Performance to figure out when your body is ready to perform and when it needs rest. I find it very useful that the ranges from 1 to 100% are color-coded. Red is everything below 33%, yellow zone is anything between 34% to 66%, and green zone, my favorite, is anything from 67% to 100%.
HRV is Heart Rate Variability. It is referring to the nuanced time difference between each heartbeat; HRV is a key indicator of training adaptation and overall health. HRV recommendations will tell you when your autonomic nervous system is ready to take on a greater strain.
Resting Heart Rate is measured every night during deep sleep for consistency. A normal resting heart rate for adults ranges from 60 to 100 beats per minute. Generally, a lower heart rate at rest implies more efficient heart function and better cardiovascular fitness. A well-trained endurance athlete has a resting heart rate of 40 bpm. Miguel Indurain, a five-time Tour de France winner and Olympic gold medalist in 1996, recorded a resting heart rate of 28 bpm. But make no mistake, each body is uniquely different, and so your RHR will be different from that of others.
Respiratory rate was definitely a new concept for me. A person’s respiratory rate is the number of breaths they take per minute. The normal respiration rate for an adult at rest is 12 to 20 breaths per minute. A respiration rate under 12 or over 25 breaths per minute while resting is considered abnormal. WHOOP shows you a deviation from baseline, it could indicate a variety of physiological changes. Recently, an elevated respiratory rate has been shown to be an early indicator of COVID-19. Elevated respiratory rate can also be an indicator of other disorders. Consult with your doctor if concerned about your health.
Note: while it might be discouraging to see your recovery being too low, however, you might actually feel a lot better. Sometimes over-reliance on technology blinds our self-awareness and ability to feel what we are capable of. Tech is useful, but it isn’t everything. You’re your own manager. Calibrate the insights you see and how you feel.
Good sleep contributes to your strong immunity. It makes you feel great and ensures you perform and feel your best. Having a good night’s rest is defined not just by how long you slept, but how deep your sleep was and how many disturbances you had throughout the night, as well as the amount of time it took to fall asleep.
Sleep You Got.
The big numbers you see on the sleep performance screen are actually tappable, it took me a while to get used to it. Recognition over recall would be the best usability heuristic for this experience.
Note for the WHOOP team: The big difference between recognition and recall is the number of cues that can help memory retrieval (recall involves fewer cues than recognition). In short, make it clear to the user that the elements, in this case, the numbers, are interactable.
Time spent in Rapid Eye Movement (REM) is the “mentally restorative” stage of sleep when the brain converts short-term memories into long-term ones.
Slow Wave Sleep (SWS) is the “physically restorative” stage of sleep. It is most difficult to awaken people from slow wave sleep as it is considered to be the deepest stage of sleep.
The efficiency of your sleep. Time spent in bed vs. time spent actually sleeping. Latency measures how much time it took you to fall asleep. It’s only accurate if you remember to log in that as an activity when you’re ready actually to fall asleep. You can edit your sleep by either deleting it or editing time in bed. I never took advantage of this functionality as it felt time consuming.
Your baseline shows how much sleep you need every 24-hour period before accounting for factors like Sleep Debt and Recent Strain. I know that people generally do not like any debt, even sleep debt. But knowing where you stand might help you make a better decision around your bedtime routines and rituals.
Note: Although it is useful, this information is currently a bit hidden. You have to tap on the big numbers to dig into this dataset.
Recent Strain — Any additional strain requires you to sleep more. WHOOP shows minutes you owe your body.
Sleep Debt — The sleep debt section shows you the difference between the amount of sleep you need vs. the amount of sleep you got.
Recent Naps — This section tracks your naps. Minutes napping are subtracted from tonight’s Sleep Need. You have to log in your naps before falling asleep, which is why I have never used this feature.
Sleep coach is separated under its own tab. Tapping on the “Recommended time in bed,” you’ll be able to give the coach guidance around your sleep goals. You can specify whether you want to Perform, Peak, or Get By on a particular day. This will adjust the sleep recommendations for you on that day. Tapping on the calendar icons in the top right corner allows you to set goals around your sleeping scheduling. Let’s say Monday through Friday you’re working, homeschooling your kiddos, and aiming to squeeze a workout here and there. Obviously, your sleep will be less than ideal. But Saturdays and Sundays, you can set as your sleep depot days where you can wake up later and therefore recharge your body for more intense workouts. Choose whatever fits your life priorities.
You can track your workouts with WHOOP. It’s not the actual workout library or exercise manager, but it will give you an idea about the intensity and the effectiveness of your workout. Strain coach allows you to choose and track a specific activity, although the dropdown is a bit convoluted, and it took a bit of scrolling to find the “Weightlifting” category. In-workout Strain coach shows you today’s recommended strain target, which is a range based on your sleep and recovery levels.
The heart rate scale gives you an idea about the heart rate zones you’re entering as you work out. I find this one incredibly useful because it helps you manage what you plan to do: a cardio session or a weightlifting per given moment. Swiping left will show you your real-time chart with your heart rate. Strain coach has a “Live” feature if you like streaming your workouts. I personally don’t. Privacy is always my main concern when it gets to My way of capturing a workout is a selfie or a photo. You can save or discard the activity data.
Weekly & Monthly Reports
With fitness apps, there’s always more data to show than mobile real estate allows. To meaningfully unfold the story behind the numbers, WHOOP has a web-based app companion, which is an extension of your app. Initially, you’ll have to unlock these types of reports by simply using the app and the wristband consistently for 7 days first. WHOOP generates weekly and monthly reports for you. Eventually, you’ll unlock your monthly performance report. This is where the web app comes in handy; it lets you see the changes month to month. The format you get in the app is PDF, which is less than ideal, but like any new product — you got to start somewhere.
It is important to keep in mind that WHOOP is a new product and very likely that not all the features are built out as a final solution. This applies to the community the way it is right now. A truly engaging community requires posting, commenting, moderation, and sharing functionalities to really start bringing people into this feed and nudge social behavior. For now, there is just the leaderboard based on Rest, Recovery, and Sleep Stats. This is a good quick start but is not a long-term solution, so I suspect there is more to come this or next year.
Opportunities for improvement.
User experience for such an ambitious product that aims to achieve and unfold so many insights presents a real challenge. WHOOP has taken this challenge head on and while the product and experience is inspiring and useful they will need to continue optimizing and improving the experience. To be more specific: simpler onboarding experience, autofill support, information architecture presents navigation problems, tap/touch/gesture ergonomics causes reach issues. I find the journaling interaction paradigm and the timing of this feature to be the most frustrating part of the app.
Practical gender-specific insights. Biometrics trackers have to get skinnier if intended to be worn 24/7. Women tend to wear their clothes with tighter sleeves, and the wristband might get a bit too tight depending on the outfit. I think it is also important to recognize and embrace the differences between male and female physiology. At this point, we can and should successfully implement menstruation prediction for women and tracking capabilities as a part of a performance tracker. There is a normal physiological change in sleep patterns, recovery, and strain potential during those days.
WHOOP 3.0 is definitely a keeper. The software provides an enormous amount of data and insight about your body. It is a great tool for serious fitness enthusiasts, athletes, coaches, and those who simply want to live better and get healthier. The learning curve and the cognitive load are a bit too steep initially, but once you learn the app, the tool, the data, the trends, you’ll find yourself enjoying the insights about your body. The hardware is fashionable, accessible, and durable for the most part. WHOOP provides a wide range of supporting accessories to wear the tech the way you want: as a wristband, bicep sleeve, and even in a protective sleeve if you’re planning to swim with it. I was pleased with the wristband’s battery life and the ability to use the battery on the go. The price is reasonable and worth giving a try. It’s one of the most useful and impactful investments I made in 2020.