What's the Best Time to Go to Bed? One Expert's Strategies to Finding Your Right Bedtime |
Posted: September 30, 2014 |
Given the importance of a good night's sleep, how do you pick the best possible bedtime? WSJ's Heidi Mitchell and Stanford University's Dr. Rafael Pelayo discuss with Tanya Rivero. Photo: GettyMany people categorize themselves as morning larks or night owls, but even they can have trouble finding the optimal moment to turn in for the night. One expert, Rafael Pelayo, a clinical professor in the division of sleep medicine at the Stanford School of Medicine, explains the secret to sorting out bedtime and why 8-year-olds are the best sleepers. The Brain Goes Tick-Tock The suprachiasmatic nucleus, or SCN, is the part of the brain where the optic nerves crisscross, (near the hypothalamus), says Dr. Pelayo. It actually ticks, he says, keeping time at about 24 hours and 10 minutes a day. "It's what forces us to get sleepy when it's nighttime," he says. In fact, this internal clock is so important, it gets better blood supply than any part of the brain, and is nearly impossible to destroy, even in a stroke. "There is a very basic need for us to be able to predict time," says Dr. Pelayo. Humans are diurnal, and adults aren't normally "random" sleepers. Always on Alert Humans' alertness levels aren't constant, however, adds Dr. Pelayo. "People think that sleep is like gasoline, that in the morning, just after a good sleep, you're most alert because your tank is full, but that's not the case," he says. Because of our long evolution, humans have developed sleep patterns and alertness to match needs for survival. "People are most alert in midmorning and just before going to bed; we're less alert in the late afternoon, when the days are hottest and the lions were less likely to attack us," he says, adding that this explains why many people get drowsy after lunch, but not after breakfast. Later in the day, he says, all humans have a second wind, about two to three hours before their falling-asleep time. The Cycle of Sleep The 90-minute sleep cycle also evolved from the need to be alert at times in the night. "Humans are meant to have a brief awakening every 90 minutes for 20 to 30 seconds, look around and be sure everyone is safe, and then fall back asleep," says Dr. Pelayo, which is why new mothers are able to nurse in the night and then sleep again. "If you're cozied up in bed and then begin to worry about the door being locked, eventually the biological need to sleep will overpower you. But after three to four hours, you will wake up and check the door," he says. That need for security is deep-seated, and providing a safe environment is the best way to begin the process of going to sleep. Serenity Now There is an old saying that "one hour of sleep before midnight is worth two hours after midnight," but Dr. Pelayo says this statement is totally false. "It's a mistake to go to bed too early," he says. "Trying to go to sleep when your body wants to be awake is like swimming upstream." Instead, a good strategy, says Dr. Pelayo, is to lock in the wake-up time and restrict your time in bed to your usual amount of sleep (which may not be the oft-cited eight hours). "Restricting your opportunity to sleep may actually make you go to bed later but the biologic drive to sleep will help you fall asleep faster and sleep deeper," he says. By his equation, "your ideal bedtime should be about 10 to 15 minutes before you want to fall asleep," he says. "So if you want to be up at 7:30 a.m. and want to sleep 7.5 hours, you should get into bed about 11:45 p.m." The best sleepers in our society, he says, are 8-year-olds, who still have rules about bedtimes and go to bed without any worries. To sleep like one of those serene children, says Dr. Pelayo, "put your mind at ease, say your day is done, don't spend too much time in bed and always, always get up at the same time in the morning."
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