Here’s What Staying Awake for 36 Hours Does to Your Face

Getting a good night's sleep has been linked to improved performance and cognitive function. It's also believed to influence our appearance, leading to the popular notion of "beauty sleep." But does sleep deprivation actually play a role in the way we look? As an experiment, Greg and Mitch from the AsapSCIENCE channel decided to stay awake for 36 hours, taking photos every 6 hours to track whether a lack of sleep had any impact on their appearance. And the results are...jarring.

"Scientists don't actually know why we look so messed up when we don't sleep," says Greg in the video, citing the two most popular theories from evolutionary biology which might explain it.

The first theory goes like this: When you're sleep-deprived, you have a weakened immune system and are more prone to accidents. Having this weakened state reflected in your face lets other well-rested members of your community know to avoid you. The second theory suggests that being deprived of sleep makes you more pessimistic, and less adept at exhibiting emotion.

Greg and Mitch wake up at 8 a.m. and started their day as usual (but aside from their morning coffee, no caffeine was allowed during the entire 36-hour period). The first 10 hours or so go fine, although keen napper Greg begins to struggle after that.

By 4 a.m. (around the 14 hour mark), Mitch can feel his cognitive abilities slowing down. "Any time you're trying to learn or remember something, an area in your brain called the hippocampus is really active, it's basically taking in all the information and processing it for you," he says. "But when they look at brain scans of people who are sleep-deprived, the hippocampus is basically off. On top of that, the proteins that are required to actually build connections between neurons are no longer available when you're overtired, and so effectively, it's really hard to even make a memory, physically."

Once the sun has risen again, they both begin to feel slightly re-energized, as their bodies attempt to reassert their circadian rhythms. "As the sun comes up, your body starts to produce hormones that are in sync with the daylight, which wakes your body up," explains Mitch. However, that second wind doesn't last, as their adenosine levels are through the roof, and the effects of their all-nighter begin to manifest in their faces.

At the end of the challenge, they both look noticeably different, with Greg's face in particular appearing inflamed. "I look so sad!" he says. "I would 100 percent stay away from the person on the right." Mitch also looks deeply unhappy, with more visible lines around his eyes from the sheer effort of trying to keep them open.

The takeaway from the video is pretty simple, as you might expect: getting those Zs is important. Not just for looking your best, but for being your best self (or pretty much just getting through the day like a functioning human being).

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