Bright Night-time Light Affects Your Sleep

Picture of someone hitting snooze buttonAre you having trouble sleeping soundly all night?

Did you know that exposure to the bright light from your phone and tablet screens can affect your internal body clock – which then affects your sleep? The body has a circadian rhythm that responds to the amount of light you are exposed to. Fifty years ago, we didn’t spend our evenings watching a movie on our laptop or entertaining ourselves with our smartphones. But today, it’s common to catch a movie on your laptop, phone or tablet. The amount of light we were exposed to from a regular TV was much lower than the bright light we receive from our screens.

The Light – Sleep Experiment

Eight researchers came up with a fascinating experiment, which was published in the Journal of Physiology April 29, 2018. The hypothesis of the researchers was that there is an unchanging association between the suppression of melatonin and the resetting of circadian rhythm as determined by light exposure. Every night, as it gets dark, the natural response of the brain is to produce melatonin, which gives us the urge to go to sleep. We all know that if we are camping, and not using artificial light sources, once it gets dark, we naturally begin to get sleepy. That’s because melatonin is being released. In today’s world, it can be pitch black outside, but if you have your iPad providing you with entertainment, it’s likely you can stay for hours. Why is this?

To find out, researchers exposed 16 healthy participants to a variety of light conditions in a 9-day inpatient setting. They wanted to know if exposure to bright lights (9,500 lux) on an intermittent basis would start to disrupt the normal circadian (waking-sleep cycle) rhythm in the participants. Exposure time was between 12 minutes up to 6.5 hours.

What happened and what can we learn?

Predictably, the bright light consistently resulted in the suppression of melatonin. It did not necessarily result in an equal disruption of their waking-sleep cycles. They concluded that simply randomly exposing subjects to bright lights would only suppress melatonin during those exposure times.

Good Sleep for You

If we are to glean some very useful information from this study, the natural conclusion is that if you spend your evening hours exposing your brain to the very bright lights of your tablet or Smartphone, you may expect to experience some difficulty getting to sleep or staying asleep.

Far better would be for you to watch a TV that is several feet away from in a room that also has room lights on, which effectively equalize the light atmosphere. Or, if you enjoy books, your best choice for a good night’s sleep is to read a book that is NOT on a Kindle or any e-reader. The good old-fashioned printed book is a friend to producing melatonin as it gets later in the evening. Many people I know take a good book to bed. It serves to relax them and allow their bodies to slow down, produce melatonin and enjoy a good night’s sleep.

For those of you who want to read the details, read the original study.

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