New Delhi: Being exposed to bright light at night, including from phones and other screens, could increase the risk of heart failure by 56%, according to a new study. Researchers warn that late-night light exposure may be a significant risk factor for cardiovascular diseases among adults aged 40 and above.

The research, led by scientists at Flinders University, Australia, analysed over 13 million hours of light exposure data collected through wrist-worn sensors on nearly 89,000 participants in the UK. The participants were tracked for more than nine years.

The findings, published in the Journal of the American Medical Association (JAMA) Network Open, revealed that exposure to light at night was also associated with a 47% higher risk of heart attack, 32% higher risk of coronary artery disease, and 28% higher risk of stroke.

“Night light exposure was a significant risk factor for developing cardiovascular diseases among adults older than 40 years,” the authors wrote.

Lead author Daniel Windred, a research associate at Flinders University, said,

“This is the first large-scale study to show that simply being exposed to light at night is a strong and independent risk factor for heart disease” he added,

“Disrupting your body's internal circadian clock by repeatedly exposing yourself to bright light at night, when it would typically be dark otherwise, will put you at a higher risk of developing dangerous heart issues.”

The study also found that women and younger people were particularly vulnerable to the harmful effects of light exposure at night.

Senior co-author Professor Sean Cain, from Flinders University's College of Medicine and Public Health, said,

“Women may be more sensitive to the effects of light disrupting their body clock, which supports earlier research findings. In fact, women exposed to high levels of night light had similar heart failure risks to men, which is unusual because women typically have some natural protection against heart disease.”

The researchers suggested that reducing light exposure at night could help lower cardiovascular risk. Using blackout curtains, dimming lights, and avoiding screens before bed may be effective strategies, they said.