Whoop has always been a wearable marketed to the most hardcore of athletes. It’s been seen on the wrists of athletes in the NBA and other pro sports leagues, which is fitting, because it’s designed to maximize training. Personally, I’ve always been hung up on one thing: I don’t want to wear something on my wrist that can’t even tell me the time of day. Call me old-fashioned, but it’s true.
But Whoop just released the fourth generation of its popular wristband, which is 33% smaller than its predecessor and also has more sensors, so I figured it was finally time to give this thing a whirl. It turns out it gets a lot of things right.
No Screen, Just Band
Whoop has always been unique in the world of wearables. For starters, it’s not something you can just buy. Instead, it’s a service you pay for: $30 a month, though it can be as cheap as $18 a month if you buy in an 18-month chunk, and the company sends you the band for free. This means that if you’ve been using Whoop for years, they’ll just send you a 4.0 band to replace your 3.0, and the new band doesn’t cost any more than the old one.
The Whoop 4.0 has a sleeker design than prior versions. At two-thirds the size of the 3.0, it’s noticeably less prominent and more comfortable when it’s on your wrist. It also claims to be the first to use a new type of battery from Sila, which has a silicone anode that boasts 17% more energy density. So, despite being smaller, the 4.0 still promises five-day battery life (though I found that sometimes it would only make it four days).
The way the Whoop recharges is extremely slick. It has a small battery pack that you just slip onto the Whoop while it’s on your wrist, so you basically don’t ever have to take it off and you don’t end up with any gaps in your data. The charger for the 4.0 is now waterproof, so you can shower or swim with it while charging if you want (or if you forget). It’s a very clever system.
The Whoop is generally worn on your wrist like a watch, but there is now a line of clothing called Whoop Body. This is a collection of shirts, shorts, bras, underwear, and bands that allow you to wear the sensor elsewhere on your body. Unfortunately, I did not have the opportunity to test these, so the Whoop 4.0 stayed on my wrist for a month, and I found it to generally be comfortable. It’s fairly low-profile, so it didn’t catch on my sleeves very often, and the woven, stretchy band is soft to the touch, though it does take a little while to dry, which caused some damp cuffs.
What Whoop Tracks
The band doesn’t have an accelerometer to count your steps or an altimeter to count the flights of stairs you ascend every day. Whoop neither knows nor cares about such trivial frivolities! It does, however, pay a lot of attention to your heart. The 4.0 band now has five LED lights (three green, one red, and one infrared) up from two in the previous generation, and it now has four photodiodes, up from one.
Using all the data the comes from those sensors, the Whoop platform is really only interested in two things: Your strain level and your recovery level (and your sleep, but that’s effectively part of your recovery). Your strain score is, essentially, how hard your heart had to work. When you do a workout, manual labor, or anything that gets your heart pumping, the band keeps track of your pulse. Afterward, you’ll see a strain score for that specific activity in the app. All of this is cumulative, and you also get a strain score for your entire day, which is on a scale from zero to 21, for some reason. Each day when you wake up the app will give you a recommended amount of strain to aim for based on how you’ve recovered from your last bout of strain.
Recovery is the other big thing Whoop looks at, and it examines how much rest you’ve gotten post-strain. As you might expect, the main way to recover is to sleep. Each evening Whoop gives you a notification about how much sleep it thinks you need to fully rest and get yourself a recovery score of 100. (Yes, the strain score is from 0-21 and recovery is 0-100 and no I don’t know why.) The band estimates when you’ve fallen asleep and when you wake up, and it does so with very solid accuracy, in my experience. While you’re sleeping it monitors your pulse, as well as heart rate variability (HRV), respiration rate, and blood oxygen levels. When you wake up, it gives you a sleep score and tells you how you’ve recovered—or how well it thinks you’ve recovered, anyway.
Not Exactly Accurate
Over the years I’ve had various friends and colleagues get somewhat obsessed with their Whoop scores, so I was excited to finally try it out for myself. The results were interesting, but they left me underwhelmed. I found Whoop’s strain metric to be somewhat inconsistent. You start off with a zero when you wake up, but I found that on many mornings it gave me a score in the low 4s before I had done anything beyond make myself breakfast (which definitely did not spike my heart rate). It seemed to work pretty well for cardio, and my strain score would scale up as expected on longer/harder runs, but Whoop doesn’t really know what to do with strength training. Doing bodyweight exercises and lifting weights is an important part of training for a lot of people, but it barely registers on the Whoop because it doesn’t cause your heart rate to spike like longer-duration cardio does. This could leave you with exhausted, twitching muscles but still a very low strain score.
I checked the Whoop against a chest strap heart rate monitor and against other wearables, and generally the heart rate was accurate, though there were instances where my reading would just drop out unexpectedly, as you can see from these random sharp valleys in this run I recorded.
Basically, I would put it on par with other current generation wearables from companies such as Polar, Suunto, and Garmin, but not above.
I had issues with the way the Whoop scores sleep and recovery, too. Sometimes my recovery score would match the way I felt in the morning, i.e. the band gave me a 75, and subjectively, yes, I felt like I was at about 75%. Other times it was inexplicably way off, and that could happen in either direction. After a very poor night of sleep, it informed me that I was well into the 80s in my recovery and primed for a day full of strain. I was exhausted and felt like a husk of myself. Another time it rated my recovery as way down in the 50s, but I actually felt great and was ready to put some work in. I did some digging, and I think the problem may be that Whoop weighs your heart rate variability (HRV) much more than it does that actual duration or quality of your sleep. HRV is certainly an important metric, but people who are in good shape typically have higher rates of HRV (which is a good thing), and I think that may skew the numbers.
Whoop vs. Garmin
It’s also worth noting that while Whoop may have been the first to really laser focus on recovery, it’s not the only wearable that does so now. Garmin, for instance, has a metric called Body Battery, which is effectively the same thing as Whoop’s recovery score, and I found it to be slightly more accurate compared to how I actually felt, subjectively. Garmin doesn’t make this number as prominent as Whoop does, but it’s right there for you if you want it.
And that brings us to the crux of the issue here. The entire time I wore the Whoop 4.0—more than a month—I also wore a Garmin watch called the Enduro. The Enduro does everything the Whoop can do, but it can also do so, so much more. Steps and altimeter? Check. Track all kinds of different indoor and outdoor sports/activities from lap-swimming to snowboarding? Yep. Do it all with GPS and the ability to show me the weather and phone notifications? Yessir. Contactless payments? Sure. And last, but not least, I don’t have to pull out my phone to find out what’s going on. If I want to see my heart rate in real time, I can just look at my wrist. If I want to set an alarm, I can do it on my wrist. If I want to know the flipping time and date, or my Body Battery level, or the number of calories I’ve burned today, it’s all right there. Several weeks of battery life? That, too. Now, the Enduro is not a cheap watch, costing around $800, but Garmin makes much cheaper multi-sport watches that do basically all of that and those watches are liable to last you many years. With Whoop costing around $30 a month, the cost would very likely become comparable in just a couple years.
The most important bit is that the Garmin can fully replace the Whoop, but the Whoop can’t at all replace the Garmin. Even if I really loved the Whoop (and I sort of did at times), I’d still want to have the Garmin on for basically any activity that I did, and wearing two watch-sized wearables is just a non-starter for me. It looks like I’m in geek-shackles.
The Whoop 4.0 isn’t “bad,” it’s just limited. It is good to see it evolve and do things the 3.0 couldn’t. For instance, if your blood oxygen suddenly drops below safe levels (which could be a sign of a real health problem, such as a covid-19 infection), it can alert you. When I got my Moderna booster shot, I woke up the next day to an alert that said my HRV had dropped, my skin temperature had risen above my average, and my recovery was very low. Yep, I felt like crap for a day. Also new in the 4.0 is a vibrating motor which you can use to set a silent alarm. You can set it to a specific time, a “sleep goal,” or when the Whoop senses that you’re in the green (i.e. you’ve reached a good level of recovery). I do not recommend that last one, as it woke me up an hour earlier than I’d hoped and I was still completely exhausted.
Whoop’s goals in and of themselves are good. The idea of calculating strain and recovery (and sleep) so you know how hard to push on any given day makes sense. The problem is that the Whoop 4.0 doesn’t absolutely nail this, and considering that’s really the only thing that it does, it needs to be effectively perfect. In contrast, there are tons of sports watches out there who do about as good of a job at addressing the strain/recovery equation, but then also do so much more. A good multi-sport watch just makes more sense for virtually everybody.