Not getting enough restful sleep? You’d be surprised what a difference a sleep mask could make. You might take for granted that the point of a sleeping mask is to completely block out any surrounding light, but it actually serves a purpose much greater than that. When your brain recognizes that you’re in total darkness, it begins producing higher amounts of melatonin, the hormone that guides you to sleep.

Biologically speaking, modern humans are designed to sync our sleeping cycles in line with the amount of sunlight outside. So back in the days before artificial light, nightclubs, and Netflix, we would return to our caves for a night of shuteye. But technology and all of these after-dark options have wreaked havoc on our natural clocks. As a result, having the sunlight shine in our eyes in the morning isn’t always the most pleasant way to be woken up. But if you’ve got a sleep mask handy, this is never a problem.

A 2009 study conducted by Chinese scientists found that subjects who wore sleep masks and earplugs as they slept were less inclined to wake up through the night, had higher levels of melatonin, and experienced more deep sleeping time versus those who didn’t.

Sleep Masks Are Perfect Travel Companions

Catching a red eye? Going on a long bus, car, or train ride? Do you feel a bit uneasy sleeping in an unfamiliar bedroom? None of these experiences are very pleasant, especially if you’re forced to sleep sitting up in the passenger seat. The simple and convenient solution is to bring along a sleep mask. Aside from these examples, a sleep mask is also effective when you’re traveling across time zones and having to consciously regulate your sleep schedule.

How to Choose the Right Sleep Mask