The Sleep Blues: Is your computer screen keeping you awake?

Blue light at night can lead to an unproductive day.By Dr. John

In 1893, Nikoli Tesla lit up the night at the Columbian Exposition in Chicago.  His inventions in alternating electric current, together with Edison’s work on filaments, allowed us to end night at will.  Now ubiquitous, artificial lighting disrupts sleep by inhibiting the production of melatonin, the light-sensitive hormone that induces sleep. As Laura Beil writes in New York Times:

Light hitting the retina suppresses the production of melatonin — and there lies the rub. In this modern world, our eyes are flooded with light well after dusk, contrary to our evolutionary programming. Scientists are just beginning to understand the potential health consequences. The disruption of circadian cycles may not just be shortchanging our sleep, they have found, but also contributing to a host of diseases.

In the computer age, we are taking the lighting revolution a step further; a step that may be giving us the Sleep Blues. While light of any wavelength can disrupt sleep, blue wavelengths, such as those emitted by the computer screen you are using, appear to be the most disruptive. Beil, quoting neurologist and sleep specialist Dr. George Brainard:

An LED screen bright enough and big enough “could be giving you an alert stimulus at a time that will frustrate your body’s ability to go to sleep later,” said Dr. Brainard. “When you turn it off, it doesn’t mean that instantly the alerting effects go away. There’s an underlying biology that’s stimulated.

Incandescent bulbs, which produce more red wavelengths, appear to inhibit melatonin production less than the blue wavelengths given off by LED monitors and energy-efficient bulbs. Thus, if you enjoy bedtime reading but are having a hard time going to sleep, an “old fashioned” bedside lamp and a print book may be your best choice.

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Dim lights at dusk for better sleep

Sleep is fundamental to good health. Sleep impacts the quality of your day, and what happens during the day impacts the quality of your sleep. While many factors affect sleep, one we can control, yet often don’t, is the intensity of light we are exposed to before bedtime.

As we saw in The End of Night, the development of the light bulb and alternating current allowed us to effectively eliminate night at will. Since most of us prefer to get a good night's sleep, recall during the Paleolithic the slow decrease in light intensity at dusk prepared the brain for sleep, primarily by the secretion of melatonin. Today, we often keep the room lights on until bedtime and then, once turned off, expect to fall asleep effortlessly. For millions of Americans, the failure to adequately prepare the brain results in nonrestorative sleep.

According to EurekAlert, the Journal of Clinical Endocrinology & Metabolism will publish an article comparing normal room light versus dim light on the secretion of melatonin:

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