The Science Behind Sleep Masks

/ July 15, 2019

The dreaded long-haul flight: engine noise, cramped seats, turbulence, cabin lights. We've all been there. How can anyone sleep in that environment? The key is to filter out as many disturbances as possible. Headphones or earplugs take care of the sounds, but light can be just as disruptive to peaceful sleep. Many people, whether traveling or at home, use sleep masks to block unwanted light. But does simply covering your eyes actually help you get better sleep? Let's find out.

Sleep mask benefits

At least one study suggests that sleep masks might help promote better sleep in otherwise inhospitable situations. Researchers in China re-created an intensive care unit and gave several volunteers sleep masks, earplugs, and melatonin to see which was the most effective sleep aid. Participants spent one peaceful night in darkness and silence, then researchers turned on the lights and pumped up the volume. As you might expect, subjects had a harder time sleeping: their melatonin levels were lower, and they reported increased anxiety as well as poor quality of rest.

Next, the subjects tried sleeping with sleep masks and earplugs. According to the authors, “use of earplugs and eye masks resulted in more REM time, shorter REM latency, less arousal...and elevated melatonin levels." People were getting to sleep faster, waking up less, and had healthier sleep hormone levels. Participants mostly found the earplugs to be effective but uncomfortable, whereas they considered the sleep masks “comfortable, helpful and easy to use." The melatonin was even more effective, but taking sleep supplements carries risks of its own.

When to use a sleep mask

Sleep masks are an easy fix when there is no other way to block disruptive light. Like patients in an ICU, passengers on a plane have no control over their environment, so a sleep mask is a great way to simulate darkness without exerting too much effort. Sleep masks are also highly portable and machine washable, so they're perfect for travel.

When it comes to sleeping at home, however, you might want to consider other solutions. As Dr. Nitun Verma, a spokesperson for the American Academy of Sleep Medicine, told Wirecutter, sleep masks can be a great way of testing whether light is a disruptive factor for you. If you try one at home and get a better night's sleep, that's a sign that you might benefit from a more a more permanent approach to light management. Like earplugs, sleep masks are uncomfortable for some people, plus they can slip or fall off during the night. Blackout shades or curtains are a better long-term strategy.

What to look for in a sleep mask

You might be tempted to choose style over function, but the most important thing about a sleep mask is that it's comfortable and fits well while blocking as much light as possible. The sleep mask should also be soft, so it doesn't irritate your skin, with a nose gap that works with your face shape. You want one that is machine-washable and has an adjustable strap—if possible, one that doesn't use velcro, which can get stuck in your hair.

There are three main types of sleep masks, each with its own benefits and drawbacks:

Standard (flat) sleep masks

The most common type of sleep mask, this is basically a flat strip of fabric (usually cotton or silk), sometimes stuffed with padding or foam. Flat sleep masks are widely available, cheap, and usually stay put throughout the night. They work for all sleep positions, but they can put pressure on your eyes, which some people find uncomfortable.

Contoured sleep masks

These sleep masks feature molded indentations around the eyes, to minimize contact and give you room to blink. They make you look a little bug-eyed, but many people find the extra space preferable to the pressure of a standard sleep mask. A contoured mask is less useful for side-sleepers, however, since its molded shape flattens out when compressed.

"Smart" sleep masks

Smart sleep masks are relatively new, but already generating a lot of hype in the sleep industry. In addition to blocking out light, they also incorporate a number of other features, including white noise tracks and pulsing LEDs to simulate natural light. Smart sleep masks promise to use scientific research and machine learning to improve our sleep, but their claims are largely untested. Plus, all of those features can make for a bulky—and costly—apparatus.

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