Electric lighting is a major culprit in our chronic state of sleep deprivation, according to a new perspective published in the journal Nature.
Dr. Charles A. Czeisler, M.D., Ph.D., a professor of sleep medicine at Harvard Medical School, makes the case that electric lighting can seriously affect our natural sleep cycles. He explained in the perspective that just like our ears are important for both hearing and balance, our eyes also have two purposes — vision and influence over our circadian clocks, because of our intrinsically photosensitive retinal ganglion cells that are sensitive to light.
When our eyes are exposed to artificial light, it stops sleep promoting neurons and activates arousing neurons, leading us to feel less sleepy, he explained.
“Technology has effectively decoupled us from the natural 24-hour day to which our bodies evolved, driving us to go to bed later,” Czeisler wrote in the perspective. “And we use caffeine in the morning to rise as early as we ever did, putting the squeeze on sleep.”
Czeisler also draws correlations between the decreases in the cost to produce artificial light and the increases in usage of that artificial light.
“Between 1950 and 2000, for example, as the cost of light production fell sixfold, UK per capita light consumption rose fourfold. This increasing light consumption has paralleled the rise in sleep deficiency,” he wrote.
He also points out that light-related sleep problems may only get worse, because LED lighting is increasingly replacing incandescent light bulbs. This makes a difference to sleep because laptops, tablets and phones all use LED lighting — which “will drive a further increase in per capita light consumption,” he wrote.
Plus, LED lights are particularly bad for our sleep because the intrinsically photosensitive retinal ganglion cells in our eyes respond more to blue and blue-green lights — like the ones typically emitted by LEDs — thereby interfering with sleep through melatonin disruption. However, he also noted that it’s possible to change the color composition of LED lighting, so that the intrinsically photosensitive retinal ganglion cells in our eyes won’t be as sensitive to it.
Sleep doctors have been telling us all along that good sleep hygiene involves unplugging before bed. HuffPost blogger Dr. Michael J. Breus points out in this blog post that not only does artificial light suppress melatonin, using technology before bed makes the brain active (making it harder to fall asleep) and also “brings the rest of your life into the bedroom, and as I’ve said before, the bedroom should be a sanctuary reserved for sleep.”
Earlier this year, a study in the journal Pediatrics showed that kids who watch TV before bed end up going to bed later than their peers who stayed screentime-free before sleeping.
And in 2011, the National Sleep Foundation conducted a survey showing that technology is a huge culprit in robbing Americans’ sleep.