Daijiworld Media Network – New Delhi

New Delhi, Jul 7: If you're in the habit of sleeping with lights on, you may want to reconsider. A recent study has linked night-time light exposure to a higher risk of five major cardiovascular diseases, including heart failure and stroke.

Conducted by an international team led by researchers at Flinders Health and Medical Research Institute in Australia, and colleagues in the UK and US, the study observed 88,905 individuals and analyzed over 13 million hours of light exposure using wrist-worn sensors.

According to the findings, people exposed to brighter night light while sleeping showed significantly higher chances of developing:

• Coronary artery disease
• Heart attack (myocardial infarction)
• Heart failure
• Irregular heartbeat (atrial fibrillation)
• Stroke

The risks were particularly higher in women and younger individuals, especially for heart failure and atrial fibrillation, the study noted.

“Night light exposure was a significant risk factor for developing cardiovascular diseases. In addition to current preventative measures, avoiding light at night may be a useful strategy for reducing risks,” the researchers said.

The team emphasized that circadian rhythm disruption caused by artificial light at night may interfere with metabolic and vascular functions, thereby elevating heart-related risks. These associations remained strong even after adjusting for lifestyle factors like smoking, alcohol, exercise, diet, and socioeconomic status.

Though the research, posted on medRxiv, is yet to be peer-reviewed, it adds to a growing body of evidence pointing to the harmful effects of unnatural light on human health.

Experts suggest simple measures like switching off overhead lights, using blackout curtains, or wearing sleep masks can help maintain darkness during sleep — potentially offering your heart a better shot at long-term health.