Tulane University study links nighttime light to heart damage

Research published in the European Heart Journal suggests that even low levels of nighttime light exposure may lead to harmful changes in heart structure and function. A study conducted by researchers at Tulane University’s Celia Scott Weatherhead School of Public Health and Tropical Medicine analyzed data from 11,017 participants to investigate the long-term effects of light during sleep.

Participants wore wrist sensors for one week to measure overnight light exposure, ranging from total darkness (0 lux) to levels exceeding 3 lux, which is comparable to a low-brightness phone screen or light from a hallway. Three years later, cardiovascular magnetic resonance scans revealed that those in the highest light-exposure group experienced thickening of the left heart chamber walls, which reduced ventricular space. The study also noted a reduced ability for the heart to flex during a heartbeat, serving as an early indicator of heart dysfunction.

Lead author Lu Qi noted that while previous studies linked light exposure to cardiovascular disease risk, this research is the first to demonstrate its link to cardiac remodeling.