We all know that, in theory, we’re supposed to sleep a lot. After all, it boosts performance, protects against injury, accelerates recovery, improves free-throw shooting, and all sorts of other wonderful things. But sometimes there’s a gap between theory and practice. Are champion athletes also champion sleepers? Or is good sleep in the “nice to have” rather than “need to have” category for ascending the heights of athletic prowess?

　　A new study in the International Journal of Sports Physiology and Performance, from sports scientists at the U.S. Olympic and Paralympic Committee led by Travis Anderson, dives into the real-world sleep habits of more than 1,600 Olympic and Paralympic athletes. In the lead-up to the Tokyo Games in 2021, they filled out a questionnaire called the Pittsburgh Sleep Quality Index. The results offer insights into the typical sleep patterns for male versus female athletes, summer versus winter Olympians, and team versus individual sports. They also suggest that a surprising number of athletes aren’t sleeping as much or as well as they’d like.

　　In this age of ubiquitous self-tracking, you may wonder why they’re using a questionnaire rather than some form of objective sleep tracking. The simple answer is logistics: proper sleep studies are complicated and invasive. Even wearable tech devices would have been difficult to administer to 1,600 athletes scattered around the country, and their accuracy is questionable anyway. Moreover, imposing sleep tracking on athletes is a delicate proposition, and there’s a risk it can create anxiety and interfere with the sleep it’s supposed to measure. A few years ago, Charles Samuels, the sleep doctor who works with Canada’s Olympic teams, told me that the best way to assess how someone is sleeping is to ask them, “How are you sleeping?”

　　The biggest result is that roughly 40 percent of the athletes were rated as having poor sleep based on their PSQI scores. The scores take into account factors like how long you typically sleep, how long it takes you to drift off, how often your sleep is disturbed, whether you take sleep medications, and so on. The results are in line with a recent study of Dutch Olympic athletes, which found that 41 percent were poor sleepers. Similarly, an Australian study in 2021 pegged 52 percent of Olympians as poor sleepers.

　　One of the goals of the study was to provide normative values—that is, to offer some context on what’s normal for hard-training athletes, as opposed to for the general population on whom the PSQI was first tested. The PSQI is scored out of 21, with higher scores indicating a greater number or greater severity of sleep problems. You’re classified as a poor sleeper if you score 5 or more. The average among U.S. Olympics was 4.3; a quarter scored above 6; 10 percent scored above 8; and 5 percent scored above 10. The highest single value was 16. (The lowest was zero, and boy do I envy those people!)

　　There are plenty of reasons athletes might have trouble sleeping. If you have a 6:00 A.M. training session, you’re going to have trouble getting all the sleep you might like. If you’re traveling frequently across time zones to get to races or training camps, that will cost you. If your legs are aching from hard training, or your mind is racing before or after a competition, you won’t sleep well. The survey results don’t tell us exactly what’s happening, but they suggest that someone who scores 5 or 6 on the PSQI, while officially classified as a “poor sleeper,” is pretty typical for a serious athlete.

　　The main difference between this study and previous ones is that it has way more athletes, which makes it possible to slice and dice the data into subcategories. Most notably, despite typically going to bed a few minutes earlier, women had worse sleep quality: an average of 4.7 on the PSQI compared to 3.9 for men. That’s a pattern that has shown up in some but not all previous studies. Among the specific differences were that women were less likely to report falling asleep right away after going to bed, and more likely to report using sleep medications. One theory is that the variation in sex hormones across the menstrual cycle might interfere with sleep, but this study doesn’t tell us anything about the mechanisms, and the authors point out that it’s not really clear whether the small differences observed have any practical relevance.

　　The only difference between summer and winter athletes was that the winter athletes went to bed later and got up later, perhaps because there’s less light in the morning during the winter. There were no differences between Olympic and Paralympic athletes, even though factors like disrupted circadian rhythms in visually impaired athletes might lead us to expect more problems for the Paralympians. Team-sport athletes got up earlier and had poorer sleep than individual-sport athletes, but that pattern clashes with some previous studies. Overall, I’d guess that all these sub-patterns are confounded by the huge variety of sports in the sample. Runners are probably like runners, regardless of sex or Paralympic classification; they’re not like platform divers.

　　One way of interpreting all this data is that sleep is a great untapped frontier. If 40 percent of athletes are poor sleepers, just imagine your edge if you can master it. The other interpretation is that sleep can’t be that important, if all these Olympians can’t get it right. I’ll take a middle position, as is my wont. I think sleep is important for performance (not to mention for not feeling like crap all day). But I don’t think it’s one of those quantities that rewards relentless self-optimization. “If you get what you need,” Charles Samuels told me, “that’s as good as it gets.” Take your sleep habits seriously, but remember that if you still have some problems, you’re in very good—Olympic-level, to be precise—company.

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