Here’s Why Total Darkness Can Help You Sleep Better

How many times have you gotten cranky when your partner has the reading light on next to you in bed, or when sunlight is streaming through the windows when you’re trying to fall asleep?

Many things can impact our ability to sleep. “Caffeine, noisy sleep environments and restless bed partners (including pets) are frequently recognized as disruptors of sleep, but light can negatively affect our sleep as well,” says sleep disorders specialist Christen Cheuvront, MSN, APRN-CNP.

Here’s what you need to know about the link between sleep and light.

Importance of sleep

First, let’s go over why sleep is so important in the first place. And why even a seemingly small annoyance — like a light — can impact your sleep and overall health more than you may think.

Imagine your body is like a superhero, and sleep is its secret power. Depending on your age, you probably need about seven to eight hours of sleep a night at a minimum. Your sleep quantity and quality affect a tremendous amount of your body’s functions, including:

• Energy levels.
• Mood and memory.
• Heart health.
• Weight gain.
• Stress levels.

A lack of quality sleep is associated with everything from sleep deprivation, high blood pressure and diabetes to obesity and depression. Getting enough sleep really is one of the most important aspects of healthy living.

How keeping the lights on affects sleep

Light stimulates your brain, making it more alert. If there’s light in your bedroom — even if your eyes are closed — it can still impact your sleep by preventing your brain from fully entering the deep and restorative stages of sleep.

A 2016 study looked at the amount of light people were exposed to at night. The researchers found that those who had light exposure while sleeping got about 10 minutes less sleep per night. They also were more likely to report fatigue, wake up confused during the night, and have excessive sleepiness and impaired functioning during the day.

Although the study doesn’t prove cause and effect, the researchers believe that intense outdoor illumination in the evening affects sleep quality. Those who lived in cities with a population of 500,000 or more were exposed to street lights three to six times more intensely than those who lived in lesser-populated areas. And people with high nighttime light exposure, for example, were more likely than those in low-lit regions of the country to be dissatisfied with their sleep quantity or quality.

So, why does light (or lack of it) seem to have such a significant impact on our sleep? Here’s how artificial light may affect your ZZZs:

Suppresses your melatonin

When it’s dark, your brain produces a sleep-promoting hormone called melatonin, which helps you feel sleepy and regulates your sleep-wake cycle. Your levels of melatonin naturally rise in the evening, but exposure to light delays the release of that hormone.

This is especially true for bright lights and blue light from screens and certain bulbs, which can make it even harder for you to fall asleep.

Disrupts your circadian rhythm

Your body has a natural internal clock called the circadian rhythm that helps regulate your sleep-wake cycles. Light is a powerful signal for directing those cycles on and off, like a switch.

“Our brain is signaled by light to activate other organs in the body, which control metabolism, digestion and immune function,” says Cheuvront. “Light exposure essentially causes a trickle-down effect that influences the timing of these bodily functions. When we are exposed to light during sleep, our circadian rhythm becomes disrupted.”

We take cues from the intensity and timing of light to help us sleep and wake up. Sleeping with lights on, especially if they’re bright, can confuse your body’s internal clock and disrupt your natural sleep patterns.

How to avoid light at bedtime

If you live near bright street lights, it’s a good idea to take some preventive measures. Some ways to avoid light disruptions while falling asleep include:

• Use blackout shades or drapes.
• Wear an eye mask.
• Cover your phone and other electronics.
• Minimize light from alarm clocks.
• Use nightlights in hallways and bathrooms rather than leaving lights on.

“Blackout curtains and eye masks are great tools, especially for night shift workers,” reiterates Cheuvront. “When shift workers need to sleep during the day, it can be challenging if sunlight is streaming in through the windows.” 

Other potential sleep disruptors

Another big source of sleep disturbance that ties in with light exposure is our screens. Yes, your phone is a form of light, too. And a sinister one before bed.

If you’re the type of person who loves to scroll through your social media or watch videos on your smartphone before dozing off, it’s a good time to kick this habit. Smartphones give off a blue light that mimics daylight, which, in turn, prevents you from falling asleep promptly.

Try to adjust your evening tendencies by cutting off your screen time one hour before bed (this includes TVs, too!). It might be a hard adjustment at first, but take note of how much this impacts the quality of your sleep!

The bottom line

Having the best environment for falling asleep can make a big impact on your sleep quality. You want your space to feel calming and serene in every way so your brain knows when it’s time to hit the hay.

Light exposure affects our circadian rhythm and melatonin production, so try cutting down on how much light bursts into your room at night. If you’re still having trouble falling asleep, talk to a healthcare provider for guidance.