Research shows that exposure to bright light at night raises mortality risk, particularly from heart disease and diabetes, but seeking daylight could lower these risks and promote longevity. Study: Brighter nights and darker days predict higher mortality risk: A prospective analysis of personal light exposure in >88,000 individuals. Image Credit: VesnaArt / Shutterstock In a recent study published in the journal Proceedings of the National Academy of Sciences , researchers investigated whether personal day and night light exposure and circadian rhythm disruption could predict the risk of mortality.
They found that exposure to brighter daytime light reduced mortality risk. In comparison, exposure to brighter nighttime light and disrupted circadian rhythms (low amplitude, early or late phase) increased mortality risk, particularly for cardiometabolic causes, which showed stronger associations than other causes. Background Cardiometabolic risk peaks at night: Exposure to the brightest night light between 2:30 and 3:00 AM increased cardiometabolic mortality risk by up to 67%, highlighting how night light during these sensitive hours disrupts circadian rhythms.
Disruption of the circadian rhythm is linked to various adverse health outcomes, including an increased risk of premature mortality. Nighttime light exposure shifts the timing and weakens the signal of the circadian pacemaker in the hypothalamus, leading to circadian disruption. Animal studies show that exposure to light at.