Why ‘beauty sleep’ is real, according to doctors

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“Are you okay? You look tired.”

I can’t come close to counting how many times someone has said this to me, and no matter the empathetic tone in their voice, it’s never a compliment. Basically, they’re saying I look like crap — specifically my face. My eyes are puffy and red with dark half-moons below. My skin is blotchy and my coloring is wan.

On these occasions, you could say I didn’t get my “beauty sleep,” (a term that, according to Dictionary.com, is defined as “sleep before midnight, assumed to be necessary for one’s beauty” and “any extra sleep”); but actually what I probably didn’t get, was a good night’s sleep, period.

The act of sleep, doctors concur, plays a chief role in giving one a healthy appearance. This is a fact that many of us can vouch for even if we don’t know the science behind it. A new survey by Sealy in the UK found that well-rested people reported having brighter eyes (42 percent), a brighter complexion (21 percent), clearer skin (20 percent), fewer wrinkles (17 percent) and improved skin condition (11 percent).

What is it about sleep that makes our skin look better, and inversely, why does sleep deprivation take its toll not only on the way we feel, but the way we look, specifically our faces?

Sleep is a nightly dive into a ‘fountain of youth’

“Sleep is incredibly important for physical appearance,” Dr. Mikhail Varshavski, aka Dr. Mike (as well as “Instagram’s Hot Doctor”), an osteopathic doctor tells NBC News Better. “Sleep is a regenerative process where we heal and where our neurons build strong connections. It’s like a fountain of youth that we dive in to every night.”

This fountain of youth phenomenon cannot happen while awake, because, as Dr. Jeffrey Durmer, neurologist, systems neuroscientist, sleep medicine physician and chief medical officer of Fusion Health explains, it requires the highly active process of sleep.

“When you sleep, you’re going through choreographed cycles of REM and non-REM [states] that can’t happen when you’re awake — even if you’re lying down with your eyes closed,” Dr. Durmer says, adding that it’s largely during non-REM sleep (about four of eight hours of sleep, and usually experienced in the early onset of a deep sleep, he adds), that this skin-repairing process occurs.

Sleep is nature’s anti-inflammatory

Ever twist your ankle, ice it, then go to bed and find the next day the swelling has subsided? The ice may have helped, but the sleep was also crucial, because sleep reduces anti-inflammatory agents.

“You make anti-inflammatory cytokines while you sleep, which help heal and reduce the impact of damages done throughout the day,” says Durmer, citing sun exposure and pollution as typical daily skin damagers.