We’re supposed to spend one third of our lives catching zzzs, so we’ve had enough experience at this point to call ourselves bona fide experts. But some of our most basic assumptions—REM sleep is the most important; if you're waking up in the middle of the night, you're not sleeping well; you shouldn't sleep with the TV on—aren't exactly true. We asked the real sleep experts to pull back the curtain on our biggest misconceptions. Get their take below.

1. You can get by on less than seven hours per night.

“Some rare people truly can, but the overwhelming majority need the proper seven to eight hours that we recommend. The initial consequences may be subtle, such as slightly delayed reaction time, increased irritability, or craving more junk food. Long term, the consequences of lack of sleep can be higher blood pressure and increased risk of cardiovascular disease and diabetes.” Daniel Barone, M.D., sleep medicine specialist at New York-Presbyterian

2. Waking up in the middle of the night means you’re not sleeping well.

“The truth is that we go through stages and cycles of sleep throughout the night, and it's normal to wake up (briefly) between cycles. If you feel relatively rested during the day, waking up to roll over a few times a night is probably not a reason to worry.” Haley Byers, Ph.D., board-certified specialist in behavioral sleep medicine

3. You get sleepy when you’re bored.

“Boredom unmasks existing sleep deprivation but does not make you sleepy on its own.” Rafael Pelayo, M.D., clinical professor of psychiatry and behavioral sciences at Stanford Center for Sleep Sciences and Medicine

4. Sleeping with the TV on is a big no-no.

Watching TV in Bed

“I personally have the TV on every night as I fall asleep. I’m probably the only sleep doctor in the universe who will say that it's OK for a few reasons. Number one is that most TVs have sleep timers, so they will turn off in the middle of the night, and number two is that the blue light emitted by the TV is extremely limited. Television is often used as a distraction, and we want to do something that’s calming, relaxing, and distracting as we prepare to go to sleep.” Michael Breus, Ph.D., board-certified sleep specialist and author of Good Night

5. High achievers don't need to sleep a lot.

“Sleep is for everyone. Is crucial for optimal performance and physical and mental health. High achievers appear to need less sleep, but so far this is limited to anecdotal evidence. In fact, scientific investigations have shown that in children and adolescents, more sleep is associated with better school performance.” June Chi-Yan Lo, Ph.D., research fellow in the Centre for Cognitive Neuroscience at Duke Medical School

6. The brain rests while you sleep.

“Sleep is not only important for the brain but also for the body. A recent study showed that fat cells taken from the abdominal area respond differently to insulin following a period of sleep loss, suggesting that sleep may be an important regulator of energy metabolism in peripheral tissues. Plus, there are stages during sleep when the brain is quite active—as active as it is during waking hours.” Erin Hanlon, Ph.D., research associate in endocrinology at the University of Chicago

7. REM sleep is the deepest and most important phase.

“This is not true. Slow wave sleep is by far the deepest stage. This is considered to be restorative sleep. It is also the stage of sleep in which most of your growth hormone is secreted—it is secreted in bursts throughout the day, but there is a very large release about an hour after sleep onset during SWS.” Kimberly Fenn, Ph.D., associate professor of psychology at Michigan State University

8. All sleep is created equal.

“Overweight people who snore, for example, may not even realize that their sleep is very disturbed. They may think they get enough sleep and don't understand why they feel tired during the day. The same applies to alcohol: It can help you get to sleep, but the normal pattern of sleep will be disturbed, and you may not get enough deep sleep. So your time in bed may be OK, but sleep duration is not.”Simon Archer, Ph.D, head of the department of biochemical sciences at the University of Surrey

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