Seven is the new eight. That’s what the headlines have been saying recently, in the wake of the Wall Street Journal’s report that the Centers for Disease Control is rethinking how much sleep we truly need to optimize our health. If you’re an athlete, however, think again; seven is not your lucky number.
While many athletes barely skim that seven hour mark, their performance improves remarkably with more sleep. A lot more sleep.
After Stanford University basketball players spent five to seven weeks sleeping at least 10 hours a night (when they had been sleeping six to nine hours), their performance shot up like they’d doped. They had faster sprint times and shooting accuracy. They also felt their overall physical and mental well-being improved during games and practice.
The body’s major restorative functions “like muscle growth, tissue repair, protein synthesis, and growth hormone release occur mostly, or in some cases only, during sleep,” Harvard Medical School explains. It makes sense that athletes who tax their muscles more than the average person need more sleep to fix the damage. It appears that extra, above eight-hour sleep benefits athletes rather than contributing to an early demise. “You can never get 'too much' sleep,” University of Pennsylvania sleep researcher Dr. Sigrid Veasey wrote Outside in an email. “When you have had enough sleep you will wake up.”
(And you'll be more alert and have improved cognitive function if you're getting eight hours, she adds)
So where does the seven-hour ideal come from? Support for the less-is-more position has been building since 2002, when researchers published a study involving more than 1.1 million people. In it, scientists concluded that people who sleep about seven hours a night live longer than those who get more or less zzz's. In fact, sleeping longer than eight hours a night, the researchers noted, is associated with health issues such as diabetes, obesity, and cardiovascular disease.
“It is important to understand that this 7 vs. 8 hours finding was not a carefully controlled study but is an association found retrospectively…this pertains only to longevity,” Veasey wrote. It’s entirely possible that illness caused people surveyed to sleep longer, not the other way around.
Bottom Line: How much is “enough” varies from person to person. While some people may thrive on seven hours of sleep, others may need nine to shine. If you’re active, science says you should aim for at least eight. But if you get more, you’ll likely be doing your athleticism a favor; Lebron James and Roger Federer reportedly sleep 12 hours a night. And, you know, they’re pretty good.