top of page

How Does Light Affect Your Sleep?


Boy reading book with a flashlight
Image by Amberrose Nelson on Pixabay

If you ask your doctor, “How does light affect your sleep?” his answer might surprise you. Not only does it affect you throughout the day, but the type of light you are exposed to affects your sleep even more. Learning to regulate the amount and kind of light you expose yourself to during the day can help you sleep better at night.


The Importance of Circadian Rhythms

Circadian rhythms help your brain regulate your sleep-wake cycle. As your body encounters natural light in the early morning hours, it sets an earlier sleep schedule in your brain. But as you expose it to light in the evening, the sleep cycle regulates itself to light by forcing this sleep cycle further back. At night, the more light you are exposed to, the later your body will be tired enough to go to bed.

Unfortunately, the type and color of light you are exposed to throughout the day also affect when you fall asleep and the quality of your sleep. Even in small doses, artificial light can negatively affect your circadian rhythm. Light also affects your body’s production of melatonin, a hormone your body secretes to make you feel tired, effectively telling your body it’s time to go to bed.


Artificial Light’s Effect

Artificial light is a kryptonite to your sleep cycle. Before electronic devices, your internal clock used the suns rising and setting to reset itself. Electronic devices emit a blue light that disturbs melatonin production and leaves you awake longer.

While the high-frequency waves of blue light keep you alert and stimulate your brain, it reduces the production of melatonin, and you remain awake late into the night.

Changing the times you are on electronic devices can reset your circadian rhythm and enhance your sleep. Blue light affects your sleep cycle and can also impact cardiac conditions, weight gain, metabolism, and mood.

Not all artificial light is the same. Devices have different brightness settings that adjust their illumination. While the brightness appears the same, how your brain and eyes perceive it is completely different.


Woman exposed to a sunrise
Image by Avi Chomotovski from Pixabay

Natural Light's Effect

In research studies where they wonder, “How does light affect your sleep?” It has been proven that daylight profoundly influences sleep. In fact, older studies show you should have exposure to natural light for at least thirty minutes daily. Newer studies indicate you should get natural light when the sky is overcast because the light in your eyes will help reset your sleep cycle.

The more natural light you absorb, the better you will sleep at night. Think of a day at the beach. You are awake all day, but once you get home, you say all the swimming made you tired. While that may be somewhat true. All the natural light exposure moved your inner sleep clock backward. So when the sun goes down, your body tells you it is tired, and you sleep well.


Dark Rooms Enhance Sleep

When it comes to sleeping, the rule of thumb is the darker, the better. The darkness reduces sleep disruption and distractions. Eyelids aren’t enough to block out light. Despite closing your eyes, small light levels interfere with your circadian rhythm. Low light causes eye strain through discomfort, blurry vision, sore eyes, and fatigue.

Low levels of light also disrupt how your circadian rhythm regulates your metabolism. Even if you sleep well, it can cause weight gain. A five-year study of women who slept with the TV or light on were more likely to gain ten pounds.


Using Light to Your Advantage

Using light strategically throughout your day can help you sleep much better at night. Natural morning light will set your body’s sleep clock. Adding more exposure to natural light throughout the day will reaffirm your body’s sleep-wake schedule.

A recent study was done at the University of Washington. Its results proved that midday sunlight exposure was more effective than morning light. It also showed every hour of additional daylight you’re exposed to improves your circadian rhythms.

An even balance of natural and artificial light will help your sleep the most. Less screen time or time using blue-blocking glasses is extremely helpful. Be conscious of artificial lighting. It is hard to avoid.

Don’t nap for more than thirty minutes. A twenty-minute nap is ideal. Resting in a lighted room will ensure you don’t get deep sleep and won’t sleep for long. Never nap in a dark room. It is counterproductive!

Computer, tablet and cell phone that emits blue light
Image by Firmbee from Pixabay

Suggestions for Better Sleep

The following suggestions can help you get quality sleep. There are times of the day when your circadian sleep rhythms are most sensitive to the light. They are one hour after you wake up, all night, and two hours before your regular bedtime.

  • Avoid bright lighting two hours before you go to bed.

  • Avoid electronics one hour before you go to sleep.

  • Keep the lights dim in your room for the last two hours of your day.

  • If you need a night light, use orange, red, or yellow lights. They are less likely to interfere with sleep.

  • If you get tired too early, use bright lighting to stay awake.

  • Catch up on sleep by going to bed a little earlier.

When waking up during the night or too early in the morning, keep the lights dim so you can fall back asleep. Avoid looking at your phone to keep the light from waking you.


As people age, have mobility issues, or have physical disabilities, lighting may be needed in the hallway. The of use yellow, red, or orange light will give enough light to avoid falls but will not completely wake you up. Use the same lights in rooms where children need nightlights. Kids are extremely sensitive to light. The further the light is from them, the better.


Individuals who work the night shift are prone to sleeping issues. Make sure to expose yourself to early natural light after leaving work and before bed. Use room-darkening curtains and an eye mask made to keep out light. Limit your exposure to blue light during your shift. If you feel tired at work, go somewhere to get brighter light.


Putting Sleep to Bed

Know that you know the answer to “How does light affect your sleep? You can get the exposure to natural and artificial light you need. Using light to improve your sleep effectively resets your sleep cycle and ends in a good night’s sleep.

0 comments
bottom of page