Light pollution in the bedroom could raise sleepers’ risk of heart disease, research claims.
Exposure to light at night, from electronic devices, street lamps or poorly drawn curtains, is never good for your sleep.
Now scientists from Australia say the disruption that light causes to the body’s natural clock, known as the circadian rhythm, could have deadly consequences.
Researchers took data from nearly 90,000 UK participants, who were given wrist-worn light sensors to wear as they slept.
The researchers then mapped their light exposure during the night to diagnoses of different types of heart disease, including coronary artery disease, heart attack, heart failure, atrial fibrillation and stroke.
Those who were exposed to more light at night were found to be at higher risk of developing all five conditions, regardless of the length or quality of their sleep.
Participants who had the highest light exposure were 56 per cent more likely to experience heart failure, and 47 per cent more likely to have a heart attack.
This group was also 32 per cent more likely to develop coronary artery disease and 30 per cent more likely to have a stroke.

Light pollution in the bedroom could raise sleepers’ risk of heart disease, research claims (Stock image)

Scientists from Australia say the disruption that light causes to the body’s natural clock, known as the circadian rhythm, could have deadly consequences (Stock image)
Women with high night-light exposure were more likely to experience heart failure and coronary heart disease, whereas younger participants in this category were at greater risk of heart failure and atrial fibrillation, a common heart rhythm problem.
The effects of light exposure could be due to its disruption of the body’s natural sleep-wake cycle, the researchers suggested.
This disturbance to the body clock could trigger metabolic and vascular changes that elevate the risk of various heart conditions.
To reduce your risk, the study’s lead author, Flinders University researcher Dr Daniel P. Windred, said you should try to avoid night light as much as possible.
‘Current recommendations for preventing cardiovascular diseases include a healthy diet, physical activity and avoiding alcohol and tobacco,’ he said.
‘This is the first study of light exposure patterns and incident cardiovascular diseases, establishing night light as an important new risk factor.’