Does moderate light exposure during sleep impair cardiometabolic function in healthy adults?
Moderate light exposure during sleep impairs cardiometabolic function by increasing heart rate, decreasing heart rate variability, and increasing insulin resistance, potentially mediated by sympathetic activation.
SignificanceAmbient nighttime light exposure is implicated as a risk factor for adverse health outcomes, including cardiometabolic disease. However, the effects of nighttime light exposure during sleep on cardiometabolic outcomes and the related mechanisms are unclear. This 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.
Mason et al. (Mon,) studied this question.