We can track almost everything about our health today—our pace on a run, our heart rate, our heart rate variability (HRV) and, of course, our sleep (or lack thereof). But what are fitness trackers actually calculating about shut-eye?
Most, including Whoop, don’t directly measure sleep (wearables don’t have the same capabilities as a kitted-out, in-hospital sleep lab). Instead, they use readings of things like movement, heart rate and HRV to estimate when we’re asleep and awake, then turn all of that information into a so-called sleep score.
That reading can help estimate how long we slept, how consistent our sleep has been, how much time we spent in different sleep stages, and how the night compares with what our body typically needs. Having all that data at your fingertips can be incredibly useful. But can obsessing over the number (especially before a big morning) sometimes do more harm than good?
We spoke to some of the world’s leading Hyrox and CrossFit athletes about their relationship with sleep tracking, and why they don’t always let the numbers have the final say.
Where can sleep scores go wrong?
According to the American Academy of Sleep Medicine 48% of adults in the US have used a sleep tracking device to monitor their sleep quality and duration. (And in fact men are more likely to do so than women.) But also: 76% of adults have been kept up at night worried about not getting enough sleep.
A poor sleep score doesn’t necessarily mean you’re going to have a poor day. So while sleep is extremely important, especially for high-performers, the pressure to achieve a “perfect” night can be counterproductive. There’s even a name for it: orthosomnia, which refers to an obsession with achieving a high rating on a smart device. You might wake up feeling fine, check your score, see that it’s not great, and suddenly start worrying that you actually slept poorly.
A 2024 study of 523 people found that people showing signs of orthosomnia also reported more severe symptoms of insomnia. That's a problem. If one bad score is enough to change your mood, knock your confidence, or make you rethink your training, the number is starting to have too much influence on your routine. For athletes used to training and competing under fatigue, and traveling across time zones, sleep is only one part of the recovery picture.
That doesn’t mean you should throw your Whoop in the bin. The number can tell you something about your sleep, but it shouldn’t be the deciding factor in how you start your day.
The best athletes don’t panic after a bad night
All this raises an obvious question: What if the best thing you can do with your sleep score is occasionally ignore it? Some athletes, it seems, have arrived at that solution.
We asked Aniol Ekai, the top men's CrossFit athlete in Spain this year, what he would do if he woke up to a poor sleep score. His answer was surprisingly simple: he wouldn't believe it. “I don’t want a number telling me how I’m going to feel or how I’m going to perform that day,” he says. “Whether it [is accurate] or not almost doesn’t matter.”
By refusing to let a sleep score dictate how he feels, Ekai creates a useful bit of distance between what his tracker says and how he actually performs. “I don't check my scores a week before a big competition, because I don't want another thing to think about, including any kind of stress, unless it's life or death," he says.
So what should you pay attention to instead?
Charlie Botterill, currently ranked fourth in the world in Hyrox men’s singles, says sleep has become a much bigger focus for him this year, with a few simple habits making the difference: keeping his phone out of the bedroom for at least two hours before bed, waking up at the same time each day, and making his bedroom a better place to sleep. “Based on how much I train throughout the day, my cortisol will naturally be more elevated in the evenings, which is why keeping my phone away from the bedroom can help me sleep,” he says.
But even with those practices in place, staying asleep isn’t always easy. And while a disrupted night can affect his sleep score, Botterill doesn’t allow the number to determine how he approaches the day. He checks his score, but not every morning, and takes a deliberately relaxed approach to what it tells him.
Manuela García Caparrós, a Hyrox Pro athlete and former Elite 15 competitor, takes a similarly measured approach. She tracks her sleep with Garmin and Luna, but doesn’t let the data dictate her training. “If I get a bad sleep score, I always compare it with how I actually feel,” she says. Sometimes the data backs up her perception; sometimes it doesn’t. If she feels tired and the stats agree, she might reduce her training volume or prioritize recovery. But one bad night isn’t enough to change the plan. “I pay much more attention to trends over time than to a single bad night of sleep," she says. “I never make decisions based on the numbers alone.”
So yes, wearables can be hugely powerful—being able to track your recovery, strain, and sleep can give you a pretty good idea of what’s going on with your body, especially if you know what to do with the numbers. But after speaking to some of the world's top-ranked fitness athletes about how much they actually rely on their sleep scores, something else became clear: The data should never be the final word.
Instead, it’s best to look at the bigger picture. How do you feel? Are you focused? Do you have energy? And, perhaps most importantly, how does training actually feel? Tracking our sleep is useful, but it’s still just one piece of the puzzle.
A version of this story originally appeared in British GQ.