“You look tired” is a euphemism that rarely fools even a very sleep-deprived person. Whether it’s due to stress over a morning meeting or anxiety over something stupid you said at a party five years ago, all of us have had bad nights of sleep. But when you hear “you look tired” the next day, there’s only one way to interpret it: That you look like absolute shit.
And no, it’s not just you. There are several scientific reasons why you might resemble a puffy zombie when shut-eye is in short supply. When we sleep, our bodies recover in a number of ways — e.g., special enzymes are released to fix damaged cells and blood vessels are repaired to support heart health. Our skin, both the largest organ and biggest tell after having pulled an all-nighter, also uses this time to heal and rejuvenate.
Along those lines, when our skin doesn’t get repaired from rest, there’s not a lot we can do to keep from looking rough, dermatologist Rebecca Marcus explains. And given that 35 percent of people in the U.S. don’t get enough sleep, it’s fair to say a lot of us could be looking sharper.
When we first fall asleep, we release human growth hormone (HGH), which is “instrumental in repairing DNA damage, a process that’s essential in prevention of premature aging,” Marcus tells me. Likewise, “HGH has been shown to thicken the skin, which helps to maintain its youthful appearance.” This also explains why we look worse the later we go to bed. “If the onset of sleep is delayed, this can result in lower overall secretion of HGH,” Marcus says.
Melatonin, a hormone produced by the brain’s response to darkness, helps with skin repair as well because it’s an antioxidant that protects the body from free radicals. Melatonin has also “been shown to down regulate genes that play a role in the execution of UV-induced photo damage, and has been shown to have an even higher antioxidant power than Vitamin C,” Marcus explains.
Meanwhile, the skin makes collagen when we’re asleep, which is an important protein needed for elasticity and to prevent our skin from sagging. Collagen might be in many skin-care products, but experts like Marcus say it’s still necessary to get collagen through the “maintenance of circadian rhythms, further pointing to the necessity of adequate sleep for skin health and beauty.”
The skin underneath our eyes when we’re sleep deprived is another giveaway because the blood vessels in the skin in that region of our face are smaller, dermatologist Emily Wood explains. “Lack of sleep can cause vasodilation creating more prominent dark circles under the eyes,” she says, adding that the inflammation caused by a surge of cortisol people experience when they don’t sleep well contributes to puffy eyes and bigger bags underneath them.
Not to mention, she adds, “Cortisol is known to cause acne and increase sebum production,” an oily waxy substance that causes acne when we have too much of it.. She similarly cites studies that demonstrate how sleep loss dehydrates the skin, leaving a “dull, sallow appearance.”
Given how vital sleep is to our mental and physical health, Wood suspects there may be adaptive reasons for why not getting enough of it has such rapid superficial effects. “From an evolutionary standpoint, a human that fails to obtain proper sleep isn’t going to possess desirable physical traits to pass on to future offspring,” she notes.
The good news is, before you lash out at the next person who says you look tired, you can rest assured that there’s a solution — it’s called laying down.