How Much Sleep Do You Need?
Sleep scientist James B. Maas, PhD, has already shown the real-world power of these findings by training pro athletes looking for an edge. For example, after working with Maas to improve her sleep habits, U.S. figure skater Sarah Hughes reported improved performance, contributing to an Olympic gold medal.
Among Maas’s other recent clients are the high school educators at Deerfield Academy in Deerfield, Mass., who were concerned by research showing that adolescents functioned poorly very early in the day. Under Maas’s guidance, Deerfield changed its starting time to allow students an extra hour of sleep, and the school’s average grades rose to a record winter-term high. Teachers reported students showed increased alertness, and visits to the health center were down 20 percent in a year when other schools reported substantial increases in flu and colds.
This raises a question that sleep scientists like Maas hear all the time: How much sleep does the average person need to function optimally, or even competently? Can some people really get by on, say, four hours of sleep a night (as Bill Clinton famously claimed was the case for him), or will chronic sleep deprivation ultimately catch up with everyone?
It depends, says Maas. While most people do well with seven and a half to eight hours, there are individuals who need less — or substantially more. “Some people find they need 10 hours,” says Maas, “and they can no more change that than they can change a size-9 shoe to a size 6. Women, especially, often need more sleep because of fluctuations in hormones, including testosterone, cortisol and melatonin during menstruation and pregnancy, and at the start of menopause. It’s ultimately in the genes.”
To figure out how much sleep you need, Maas suggests finding out what time you need to bed down to wake up in the morning without any grogginess or even an alarm. Each week go to bed 15 minutes earlier, he says, until you find how many hours you really need. He also advises getting most of your rest in a single stretch, and not in chunks. Fragmented nights compromise energy and cognition and lead to daytime exhaustion, he says. So consider sleeping alone if your partner’s snoring, wakefulness or restless legs disturb you. If you do lose time on any given night, says Maas, make up for it as soon as possible. Catch up by going to bed earlier, not sleeping in later. And make up the sleep over a number of successive days, not all at once.
There are those rare few who truly don’t need much sleep, Maas says, but they usually come from families with a particular genetic trait. For most of us, though, the belief that we don’t need much sleep is delusional. As Maas points out, “Clinton now says he made his worst decisions on those sleepless nights.”