Close the Blinds (04-18-22)

The Mason team’s findings support calls to keep light levels low in spaces where people are sleeping.  The group reports that their “laboratory study shows that, in healthy adults, one night of moderate (100 lx) light exposure during sleep increases nighttime heart rate, decreases heart rate variability (higher sympathovagal balance), and increases next-morning insulin resistance when compared to sleep in a dimly lit (<3 lx) environment. Moreover, a positive relationship between higher sympathovagal balance and insulin levels suggests that sympathetic activation may play a role in the observed light-induced changes in insulin sensitivity. . . . Attention to avoiding exposure to light at night during sleep may be beneficial for cardiometabolic health.”

Ivy Mason, Daniela Grimaldi, Kathryn Reid, and Phyllis Zee.  2022. “Light Exposure During Sleep Impairs Cardiometabilic Function.”  Proceedings of the National Academy of Sciences, vol. 119, no. 12, e2113290119,