The Washington PostThe Washington Post

Why falling asleep with the lights on is bad for your health

By Richard Sima

01 Dec 2022 · 4 min read

Editor's Note

Do you ever fall asleep with the lights on? The Washington Post dives into research which explains it might not be so good for our health.

Many of us are surrounded by light at night - from streetlights streaming through our windows to televisions and smartphones by our beds. And now research shows that exposure to light at night in the hours before bedtime and even during sleep can be detrimental to our health.

Light is a key regulator of our brain's biological clock, known as the suprachiasmatic nucleus. "Light is powerful in that it can synchronize rhythms and, at the wrong time, it can desynchronize rhythms," said Phyllis Zee, neurologist and director of the Center for Circadian and Sleep Medicine at Northwestern University Feinberg School of Medicine.

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