Night light thickens heart muscle, study warns

Exposure to light during sleep may negatively impact heart health, potentially leading to cardiovascular disease. A recent study indicated that sleeping with more than 3 lux of light can cause thickening of the heart muscle walls, specifically the left ventricle.

This thickening reduces the heart's ability to pump blood effectively and can be an early sign of heart dysfunction. The extent of this cardiac remodeling appears to increase with brighter bedroom environments.

Researchers analyzed data from over 11,000 participants in the U.K. Biobank study. Participants wore wrist sensors to measure light exposure over seven days. Three years later, cardiovascular MRIs revealed changes in heart structure and function.

While light pollution is identified as a risk factor, shorter sleep durations, directly linked to night light exposure, accounted for a significant portion of the observed impact. Other factors like increased stress and biological changes may also play a role.

Experts advise minimizing light exposure during sleep by using blackout curtains, turning off unnecessary lights, and considering sleep masks. Choosing warm-toned, dim lighting for any necessary nightlights is also recommended.