The Dark Side of Night Light

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May 12, 2014


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This post is available in: Spanish

What’s the last thing you do before you close your eyes to go to sleep for the night?  The answer to that question and whether you sleep at night at all – due to shift work – could be affecting your health and demeanor more than you know.

Recently, there’s been a lot of buzz about electronic devices like TVs, smartphones, tablets and laptops and their “blue-light-emitting” screens affecting our ability to fall asleep and stay asleep. Special eyewear is being manufactured that claims to block blue lights for a “better night’s sleep.”

And while even decades-old science supports that blue lights have the strongest tendency to disrupt our body’s awake-sleep cycle, or circadian rhythm, sleep experts say the blue-light phenomenon is only part of the trend toward less sleep.

“The amount of sleep we get today is 20 percent less than what it was when the light bulb was invented,” said neurologist and sleep researcher Timothy Grant, M.D., medical director of Baptist Sleep Center at Sunset.  “People used to rely on the sun to dictate their activity, and when the sun went down, they went to sleep.”

In fact, in 1981, Charles Czeisler, Ph.D., M.D., of Harvard Medical School, showed evidence that a person’s circadian rhythm relies on periods of light exposure and darkness.

“Normally, the decrease of light exposure at nighttime triggers our brain’s melatonin production,” Dr. Grant said. “That’s key because melatonin induces tiredness and eventually sleep.”

So, when people are exposed to any prolonged light – including the high frequency of blue lights – at night, their melatonin production is suppressed and sleep is harder to achieve and maintain throughout the night.

“Using electronics, with their blue lights, right before bed and being exposed to high-efficiency light bulbs that emit higher light frequencies are throwing off our circadian rhythm,” he said.  “That leads to poor sleep architecture, so our bodies are unable to reach the deepest phases of sleep, which we need to feel rested.”  And, he says, those same devices kept at the bedside arouse our sleep subconsciously each time they ping or light up during the night, causing the same “sleep fragmentation” that prevents us from reaching those imperative parts of the sleep cycle we need.

Jeremy Tabak, M.D., medical director of Baptist Sleep Center at Galloway and Baptist Hospital’s Sleep Diagnostic Center adds that in addition to that fragmentation, we’re just not getting enough sleep, period.

“Because people are working later and have greater demands on their time, sleep is suffering,” he said.  “We’re not getting the eight hours of sleep every night that the average person needs to stay healthy.  And shift workers are more at risk for ill health related to lack of sleep, because we’ve found that circadian rhythms cannot effectively be reset to nighttime activity.”

In fact, the Nurses Health Study, he says, revealed night-shift nurses had a greater tendency for weight gain than their day-shift counterparts.  New research is pointing to even more detrimental results of sleep deprivation, including cancer, heart disease and diabetes.

“People think they are getting by with less sleep, but the reality is, they aren’t,” Dr. Tabak said.  “At the very least, our ability to concentrate, recall important information and make good judgments are all being affected by our lack of sleep.”

Tips to Improve Sleep

So how should we change our sleep habits to improve our quantity and quality of sleep?

•    Both Dr. Grant and Dr. Tabak recommend keeping electronics, including smartphones and TVs out of the bedroom.
•    If you must use a computer, tablet or smartphone at night, stop one to two hours before bedtime.
•    For TVs, set a sleep timer, so it shuts off shortly after you fall asleep.
•    Follow good sleep hygiene: Go to bed and wake up around the same time each night, and be sure your bedroom is dark, quiet, cool in temperature and comfortable.
•    Engage in wind-down activities such as reading or meditation that require less light before falling asleep.

Shift workers, both doctors say, can benefit from using light-blocking glasses toward the end of their shift and on the way home.  Also, apps and screen filters on smartphones, tablets and computers can help, too.

Overall, they advise, sleep should be a priority just like eating nutritious foods and exercising.

“Blue light is just one factor of the modern world that is conspiring to prevent people from getting to sleep,” Dr. Tabak said.  “Being aware of all the factors is key to getting a good night’s sleep.”

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