How External Lights Affect Your Sleep

This content was created by the National Sleep Foundation


How artificial light affects our sleep patterns

Whether neon numbers glare from your nightstand alarm clock, your iPhone lights up when receiving a message, or the television screen glows bright on your bedroom dresser, artificial light is all around us. While it may help us be more productive during the day, all of this artificial light comes with a cost, especially when it comes to sleep.

The Effects of Artificial Light

As lamps and indoor lights have allowed you to remain awake long past sunset, they've also caused you to move farther and farther away from natural sleep patterns. People who lived during the Industrial Age, before artificial lights, slept very differently from the way we sleep today. Many snoozed in two four-hour shifts, separated by a late-night period of being quietly awake. When artificial light is taken away, humans tend to revert back to this natural, two-shift sleep pattern.

Artificial light disrupts the body's circadian rhythm—the body’s 24-hour sleep/wake cycle—and has been shown to affect things like brain wave patterns, hormone production, and cell regulation. Disrupting this circadian rhythm has also been linked to medical issues like depression, obesity, breast and prostate cancer, and cardiovascular disease. It's even associated with sleep disorders like insomnia and [sleep_term id="1180"], possibly because it causes the suppression of melatonin, a sleep-inducing hormone.

Fixing the Problem

A few small changes can help minimize the problems associated with sleep and artificial light. For starters, don’t keep your phone near you when you sleep, and avoid all artificially lit screens (like televisions, iPads, and iPhones) right before bedtime. Shield artificial light properly in the bedroom (by turning your alarm so that the light faces away from you, for example), and use light at night only when it’s absolutely needed.