A new study adds to evidence that light at night may affect more than sleep. In an analysis of more than 11,000 people, researchers found that nighttime light exposure was linked to thicker, stiffer heart chambers and early signs of reduced heart function. The association held even after accounting for other factors, the authors report.
The findings suggest that the heart may be quietly reshaped by environmental light conditions, and that keeping bedrooms darker could be an overlooked strategy for protecting the heart. The study does not prove that light directly causes these changes, but it points to a simple, low-cost intervention worth testing further.
Because the study is observational, the authors caution that the relationship could be influenced by other variables. Still, the results reinforce the idea that light hygiene—like sleep hygiene—may matter for long-term cardiovascular health.