Overview
- People in the brightest nighttime light group had a 56% higher risk of heart failure and a 47% higher risk of heart attack, with additional increases seen for stroke, coronary artery disease and atrial fibrillation.
- The analysis tracked about 88,905 adults using wrist-worn light sensors for a week, totaling roughly 13 million hours of exposure data, with health outcomes followed for up to 9.5 years.
- Links between night light exposure and cardiovascular disease persisted after adjustment for chronotype, actigraphy-based sleep measures, physical activity and seasonal day length.
- Women and younger adults appeared more susceptible, with high night light erasing women’s usual protection against heart failure compared with men.
- Greater daytime light exposure was associated with lower cardiovascular risk, and the authors recommend dimming evening lighting, using blackout curtains and limiting screens while calling for lighting guidelines and further research.