Watts Up Doc?

Can’t fall asleep without the TV on?

This is Sandra Tsing Loh with the Loh Down on Science.

Your eyelids are drooping as you TRY to binge just one more Stranger Things episode. Unfortunately, studies show that sleeping with lights on is linked to diabetes and obesity….. But HOW?

Ivy Mason and team from Northwestern University are shining light on this mystery! 

They considered three possibilities. One – light leads to bad sleep quality. Two – light affects your body clock, including melatonin production. And three – light activates the sympathetic nervous system, increasing your heart rate and alertness.

Researchers had ten participants sleep one night in near-darkness, and another in overhead lighting. They measured their sleep quality, melatonin levels, and heart rate during sleep. 

Results? Sleep quality and melatonin aren’t affected much by lighting. BUT just one night of lighting increases heart rates during sleep… Bringing more insulin resistance the morning after! 

The researchers believe this sympathetic nervous system activation increases risk of diabetes and obesity.

So lights out at bedtime! And put that phone away!

Reference: Mason, I. C., Grimaldi, D., Reid, K. J., Warlick, C. D., Malkani, R. G., Abbott, S. M., & Zee, P. C. (2022). Light exposure during sleep impairs cardiometabolic function. Proceedings of the National Academy of Sciences, 119(12). https://doi.org/10.1073/pnas.2113290119