One in three American adults doesn't get enough sleep, according to the Centers for Disease Control and Prevention. Adults need an average of seven hours of sleep a night, and regularly not getting enough sleep increases risk of obesity, diabetes, high blood pressure and heart disease. It also impairs cognitive performance.
Here & Now's Jeremy Hobson speaks with Dr. William Dement, emeritus professor of psychiatry and behavioral sciences and founder of the Stanford Center for Sleep Sciences and Medicine.
On how many hours of sleep a person should get per night
"I think [six to eight hours of sleep] is a reasonable figure. I think, however, what I advise is every single person should try to determine their own unique sleep requirement. And again, you do that by sleeping a certain amount or being in bed a certain amount of time, and then seeing how you function during the day. If you eat lunch and then you can hardly stay awake, there's a problem."
On whether President Trump is getting enough sleep
"I'd be a little bit skeptical, but I think, you don't really know for sure how much sleep people are getting. They often are not correct in telling you. I might say I sleep six hours a night, when I really sleep seven, but I don't really keep track of it that closely. And I think you can have ups and downs. You could sleep a little less, a little more. You might take a nap, but very few people keep track of it over a sufficiently large number of days to really pin it down."
"I think, if you are sleepy, and something is coming up that's going to require alert behavior, taking a nap is a good thing. I personally have begun to nap as I've gotten older. I think naps are good ... I say an hour, could be 40 minutes, even a 10-minute nap can revitalize you."
On looking at screens before bed
"I wouldn't generalize and say, 'Absolutely 100 percent of individuals must not watch TV,' because for some people TV is kind of the — especially if they have an automatic turn-off — is kind of something that lulls you to sleep. My own personal system is to pick a radio program that is very, very dull, that kind of distracts you from any concern of, 'Why aren't I falling asleep?' I think many times people can fall asleep without realizing it, and then wake up later and think they've been awake all that time."
On what happens to our brains and our bodies when we sleep
"Well the body relaxes, there's no question about that. There are two kinds of sleep, which is very important to understand. They are as different from one another as both are from wakefulness. One state of sleep is called rapid eye movement sleep, or REM sleep. That's about 25 percent of the night. And the remainder of sleep, 75 percent on the average, is simply 'non-REM sleep.' Nightmares tend to occur in REM sleep. And night terrors, more typical of young children, would occur in non-REM sleep."
This segment aired on April 17, 2017.