Why Research Says Your Room Should Be Totally Dark At Night If You Want Better Health

It seems obvious that our bedrooms should be dark when we settle in for a night of sleep, but does the light from a night light, or even a TV, actually affect health? According to new research published in the journal Sleep, it might, particularly as we age—here's what they found.

The researchers discovered that less than half of the participants were getting five hours of total darkness while sleeping, with the rest getting exposure to light in the middle of the night.

Now, it is important to note that this study design is one of correlation (albeit with robust design and control of known confounding variables) and not necessarily causation, though the study authors explain that more research is needed here to understand this link more directly.

As lead author of the study, Minjee Kim, M.D., explains, "It's not natural to see those lights at night. Light actually turns off some of the parts in the brain that tell our body it's the daytime versus nighttime. So those signals are messed up in a way, because the circadian signal is weakened, and over time, that has implications for our health."

More research is needed to further understand the connection between light at night, circadian rhythm, and overall health, but if nothing else, these findings are one more reason to make your bedroom a sanctuary for better sleep. And that means a bedroom that's cool, quiet, and as dark as possible.