Tulane University study links nighttime light to heart damage

A study published in the European Heart Journal suggests that exposure to artificial light at night may be linked to adverse changes in heart structure and function. Researchers from Tulane University analyzed data from 11,071 participants from the UK Biobank to investigate the connection between nighttime light levels and cardiac health.

Using wrist-based light sensors to monitor exposure, the study compared individuals exposed to more than three lux of light at night with those in near-total darkness. Results indicated that higher light exposure was associated with cardiac remodeling, specifically thicker walls in the left ventricle and reduced internal chamber space. The research also noted signs of decreased heart muscle efficiency and changes in the right ventricles and left atrium.

While the observational study identifies a consistent association between nighttime light and increased risks of cardiovascular events—such as atrial fibrillation, heart attack, and stroke—researchers noted it does not prove direct causation. Experts recommend maintaining dark sleeping environments, using dimmer lights after sunset, and limiting bright screen exposure to support cardiovascular health.