Light at Night Spoils Sleep and Health
You won’t realize it’s happening, but even moderate light robs you of deep sleep and raises your heart rate
Once upon a time, humans slept in total darkness, save perhaps some bright moonlight or a soothing fire at the cave entrance. After millions of years without light switches, we’re evolutionarily programmed to rely on darkness for a good night’s sleep. So it’s no surprise that artificial light in the evening and throughout the night is bad for both sleep quality and duration, as studies have shown. Even full moons mess with human sleep.
A new study reveals that during sleep, the brain detects light that passes through our eyelids, kicking the body’s nervous system into a higher state of alert. That elevates the heart rate, reduces sleep quality, and raises risks for heart disease and diabetes.
“Even though you are asleep, your autonomic nervous system is activated,” says Daniela Grimaldi, MD, an assistant professor of neurology at Northwestern University and co-author of the research paper. “That’s bad.”
You won’t realize what’s happening
The study, done in a sleep lab, included 20 participants ages 19 to 36, none of whom had any sleep disorders or serious health issues. One…
