Considering that we’re supposed to devote roughly a third of our lives to sleep, I’ve found that it’s surprisingly misunderstood. Most of my patients know that sleep is divided into three phases: light, deep, and rapid eye movement (REM). But few realize the vital importance of deep sleep in particular. During this stage, our brains produce growth hormone (GH), which helps strengthen bones and muscles; stimulate the immune system; and synthesize proteins that do their part to keep us looking and feeling vibrant and healthy. So let’s clear up the confusion once and for all. This is the truth about deep sleep:
It’s rare to totally zonk out right after closing your eyes.
Ideally, you start with light sleep, move to deep sleep, come back to light sleep on your way to REM, and then cycle through all three stages again about four to six times before waking up. In total, you should spend about a quarter of the night in deep sleep and another quarter in REM.
You don’t dream in deep sleep.
That’s more likely to happen in the REM stage, which usually produces a state of nearly complete muscle paralysis while the brain plays out its vivid stories. REM occurs more during the second half of the night and is easily interrupted. Deep sleep happens mainly during the first half and is very hard to emerge from—even during a thunderstorm.
Deep sleep is not an indulgence.
You could survive on the other two stages alone, but deep sleep is what makes you feel rested the next day. If you’re walking around in a fog, you probably didn’t get enough. (One common saboteur is sleep apnea; you might want to ask a doctor about it, especially if you snore.)
Spa treatments can’t make up for a lack of deep sleep.
We get our true beauty rest during the first couple of hours of sleep since that’s when our GH secretion is usually highest (but we still need seven to eight hours total).
Sleeping pills aren’t the solution.
While sleep aids may make you drowsy, they won’t necessarily increase deep sleep, and some pills, including Valium, can negatively affect this all-important phase. You’re better off using tried-and-true tactics like turning your bedroom into a dark cave and exercising regularly. Other deep-sleep enhancers you won’t find in a bottle: meditation and a hot bath before bed.
W. Chris Winter, MD, is the author of The Sleep Solution: Why Your Sleep Is Broken and How to Fix It.