The Powers of a Good Night’s Rest
“We spend roughly a third of our lives asleep—obviously it has a crucial function,” Epstein says. Sleep plays important roles in repair, restoration, and memory; and lack of sleep hinders cognitive function. A recent study found that going for 18–20 hours without sleep had the same negative impact on performance as a blood alcohol level of 0.1 (0.08 is considered legally drunk in the United States).
Sleep deprivation has a similar effect on physical performance. Not only does it reduce energy and motivation, but lack of sleep has a huge impact on performance. A study at Stanford University monitored players on their varsity basketball team. Researchers asked the players to increase their sleep time to roughly 10 hours a night, compared with their normal night’s sleep of 6–9 hours. When they slept more, the players had faster sprint times. Their shooting accuracy also improved, with free-throw percentage increasing by 9% and three-point field-goal percentage increasing by 9.2%.
Studies have proven that sleep is essential to both mental and physical performance, but what’s even more interesting is that our brains never get used to sleep deprivation. “The less sleep we get at night and the longer we go without sleep the worse our performance becomes,” Epstein says. The effects of sleep deprivation are cumulative—they never plateau. However, when you ask someone if they are sleep deprived, initially they will say yes. But as they become more and more chronically sleep deprived, they will start to say they’re not sleepy. Their performance is impaired, but after a while they no longer realize the negative effect that lack of sleep is having on their minds and bodies. “We are not good judges of how we’re being affected by lack of sleep,” Epstein says.
NEXT: Sleep and Your Health