Banish light from your bedroom for better sleep, lower breast cancer risk. Or just wear sunglasses at night.

BedroomlightThe other night, I marveled at the gigantic super moon shining in the sky. That is, until I went to bed. Maybe it’s the full moon crazies that keep me up, but I rarely sleep well on these nights when the moonlight fills my bedroom.

Exposure to light, even just a tiny bit as we’re sleeping, can wreak havoc on our sleep cycles and ultimately our health. Our bodies evolved to sleep in darkness at night. Our body’s circadian rhythm or “body clock” is tied to sunlight, which controls our body’s sleep/wake cycle. According to nature, when there is no sunlight, it is time to sleep. Not read your Kindle. Not surf Facebook. Not watch Game of Thrones on your iPad.

The reality is that we’re surrounded by artificial light most of the evening, and light from a multitude of sources can pervade our bedrooms. Many modern artificial light sources typically emit blue wavelengths (or “blue light”), which inhibit sleep-promoting neurons and activate our arousal neurons.

The worst news is that studies link nighttime light exposure to cancer, particularly breast cancer. You might have been warned not to look at a computer or smartphone screen before bedtime because the “blue light” these screens radiate suppresses melatonin production. This hormone is a powerful antioxidant that reduces estrogen production. Too much estrogen is linked to increased risk of breast cancer.

An Israeli study found that women with the highest “bedroom light intensity” had a 22% higher risk of breast cancer. In fact, blind women apparently have 50% less breast cancer than sighted women. Some attribute this to the fact that blind women live in darkness 24/7 and sleep more hours, causing them to produce more melatonin. And it’s been widely reported that people who do night shift work, which can throw off the body clock, have a higher risk of cancer, such that the World Health Organization classified shift work as a risk factor for cancer.

Sleep disruption from light can also keep your body from maintaining healthy cortisol levels. Cortisol regulates the immune system while releasing cells that thwart cancer.

Besides, sleeping in a very dark room is often conducive to undisturbed sleep. I once slept on a ship for 2 weeks in a pitch-black interior cabin. I think I got some of the deepest sleep of my life on that trip.

So, aside from wearing blue-blocker sunglasses to bed at night (ah, Corey Hart), how do you deal with light in your sleep environment? Here are a couple tips:

  • Install blackout curtains. Not only do these curtains potentially help you save on energy costs, but they efficiently block out light from windows.
  • Wear a sleep mask. When I can manage to keep a sleep mask on during the night, I do sleep soundly. Sometimes masks can be too hot or irritating, or they tend to fall off. I use the popular Bucky® 40 Blinks sleep mask. It’s not perfect, but it’s the best design I have found thus far.
  • Cover your alarm clock screen. Use a towel or cloth if the light emitted is too strong. Or choose alarm clocks illuminated with red light if possible. Other colors generate light in the blue spectrum. And you always could just use a good old fashioned analog alarm clock.
  • It’s advised to stop using electronic devices about 1-2 hours before you go to bed. However, one recently released study does indicate that you may be affected less if you turn down the brightness of the screen and hold the device at least 12 inches away from your face. I have also installed f.lux software on my Mac computer, which enables my computer display to adapt to the time of day.
  • Keep nightlights on in your hallways. If you need to hit the bathroom in the middle of the night, don’t turn on the full lights.

Do you find that light affects your sleep? What solutions have you found to reduce the amount of light in your bedroom?

7 thoughts on “Banish light from your bedroom for better sleep, lower breast cancer risk. Or just wear sunglasses at night.

  1. I have definitely been a procrastinator when it comes to getting the blackout curtains, but I am definitely getting them now! I am going to get a set for my toddler’s room as well, maybe they will help him asleep through the night and a good part of the morning too:)

  2. Summer in Seattle has been killing me (sleep wise). Thanks for the very helpful tips. Glad to see that you and I agree on the best sleep mask!

  3. Great post. Even though I’m a deep sleeper, I started noticing that I slept longer and deeper after I switched my alarm clock for one that didn’t glow. Never realized that light (especially artificial light) was so damaging beyond simple sleep deprivation. Thanks for the heads up!

  4. Complete agree. I LOVE sleeping at my sisters’ homes…and why? Because they have blackout curtains in their guest rooms and I sleep like a baby. I FINALLY installed blackouts in the master bedroom a month ago and I sleep so much better.

  5. Light definitely affects sleep! Until about 6 months ago, I used to sleep inches away from our video baby monitor, which emitted a blue/green tone glow through the room. Needless to say, I did not get a restful full night of sleep for 4.5 years! Once we pulled the plug on the monitor, I noticed that I was definitely sleeping deeper for longer periods of time. Now, after reading your post I am wondering how much melatonin was suppressed…I had no idea it could lead to breast cancer risk!

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