Sleeping with Lights On? New Study Warns of Higher Heart Disease Risk

New Delhi, July 7: If you’re among those who sleep with the lights on, new research suggests it may be time to reconsider your bedtime habits. A large-scale international study has found that exposure to brighter light at night while sleeping is linked to a significantly higher risk of developing major cardiovascular diseases, including heart failure and stroke.

The study, led by researchers at the Flinders Health and Medical Research Institute in Australia and involving collaborators from the UK and US, analyzed data from nearly 89,000 individuals. Over 13 million hours of personal light exposure were tracked using wrist-worn sensors, making it the largest study of its kind to date.

Key findings:

• People exposed to brighter night light during sleep had a higher risk of:

  • Coronary artery disease

  • Heart attack (myocardial infarction)

  • Heart failure

  • Irregular heartbeat (atrial fibrillation)

  • Stroke

• The risks were especially pronounced in women (notably for heart failure and coronary artery disease) and in younger individuals (for heart failure and atrial fibrillation).

• These associations remained strong even after accounting for lifestyle factors such as smoking, alcohol consumption, exercise, diet, and socioeconomic status.

Researchers explained that artificial light at night can disrupt the body’s circadian rhythm, interfering with metabolic and vascular processes that are vital for cardiovascular health. Even brief or dim light exposure during sleep has been shown in previous studies to impair glucose metabolism and increase heart rate, possibly through heightened activation of the sympathetic nervous system.

“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 study authors emphasized.

Practical tips for better sleep and heart health:

• Switch off overhead and bedside lights before sleeping

• Use blackout curtains to block outside light

• Consider wearing a sleep mask

• Avoid screen use at least one hour before bedtime

Disclaimer:
This study has been published as a preprint on medRxiv and has not yet undergone peer review. The findings should be interpreted with caution until validated by further research. Always consult with a healthcare professional before making significant changes to your health or sleep routines.