This story appears in the April 16, 2012 “One Day, One Game” issue of ESPN The Magazine.
TEN YEARS AGO, a Stanford researcher named Cheri Mah, examining how sleep patterns affect students’ brains, came across something unexpected. Some of her test subjects happened to be Stanford swimmers, and they told Mah they set personal bests during the part of the experiment when they slept more than usual. Mah knew that many studies had reported how sleep deprivation can lead to declines in physical performance, and she wondered if those findings could be inverted: Does extra sleep boost athletic achievement?
In preliminary research on swimmers, tennis players and members of the Stanford football team, Mah kept getting the same answer: yes. And in a study recently published in the journal Sleep, she and her colleagues have jolted the world of sports analytics by essentially showing that you can get safe, legal HGH just by shutting off the lights. Over three seasons, from 2005 to 2008, the scientists looked at 11 Stanford basketball players. For two to four weeks, the Cardinal kept to their normal schedules. Then for five to seven weeks, they watched what they drank, took daytime naps and tried to sleep for 10 hours every night.
After increasing their daily rest, the players sprinted faster and said they felt better in practices and games. Their aim got better too: Their three-point shooting jumped 9.2 percentage points, and their free throw percentage increased by nine points.
What’s behind the results? Well, scientists don’t fully understand what happens while we sleep, but they know this much: Some of our genes act as internal clocks and release hormones according to cycles called circadian rhythms, which are triggered by darkness and light and alternate over 24-hour periods. When we mess with these rhythms by not getting enough sleep, our metabolism of glucose (which gives us energy) declines, and our level of cortisol (which causes stress) increases. Further, sleeping for long stretches is naturally anabolic: During deep sleep, our bodies release growth hormone, which stimulates the healing and growth of muscle and bone. So while it’s possible to push through a lack of sleep during any one day, proper sleep helps athletes in two ways. First, it boosts areas of performance that require top-notch cognitive function, like reaction time and hand-eye coordination. Second, it aids recovery from tough games and workouts.
Some athletes instinctively know this already. We hear about them, say, sleeping in the clubhouse and tend to think, How embarrassing, or worse, How lazy. But the more enlightened players know that peak performance requires proper rest. In the NBA, with its grueling schedule of nocturnal play and constant travel, guys have taken to napping during the day — Kobe Bryant even stays at a hotel before home games to catch some z’s. Three teams have consulted Dr. Charles Czeisler, director of the Division of Sleep Medicine at Harvard Medical School, for advice.
The U.S. Olympic Committee began taking the issue of adequate sleep seriously in 2005, when it consulted with sleep specialist Mark Rosekind, a former NASA scientist, to help redo rooms at the Olympic Training Center in Colorado Springs and at the 2006 Torino Olympics. Out went twin beds; in came plush-top mattresses, blackout curtains, thermostats set to cool temperatures and reliable alarm clocks. Rosekind and his colleagues pushed for the Olympians to get nine to 10 hours of sleep a night, not the five to seven most young adults manage. “People need to be as smart about sleep,” Rosekind once said, “as they are about diet and exercise.”
Wrritn By Peter Keating