WASHINGTON (dpa-AFX) - A recent study, published in the European Heart Journal, has found that being exposed to light at night may cause important and potentially harmful changes to the heart.
The study, led by Professor Lu Qi from Tulane University in New Orleans, included 11,071 people from the UK Biobank project. Each person wore a small light sensor on their wrist for seven days to measure how much light they were exposed to at night. About three years later, they had a cardiac MRI scan to check the size, shape, and function of their hearts.
The researchers found that people exposed to more light at night had a thicker wall in the left ventricle, which left less space inside the chamber. Their heart muscle also appeared to be less able to relax and stretch properly during each heartbeat, which can be an early sign of heart problems. They also found changes in other parts of the heart, including the right ventricle and the left atrium.
'This is the first study of its kind, and it shows that exposure to higher levels of light at nighttime is linked to cardiac remodelling. This is where the structure and function of the heart changes and we typically see it in response to chronic stress or injury to the heart. It's our body's way of adapting to that stress, but ultimately it weakens the heart and can lead to heart failure,' explained Professor Qi.
Based on these findings, doctors treating people with heart failure or atrial fibrillation should ask about their patients' sleeping environment. They may want to know how dark the bedroom is, whether the person works night shifts, and how much they use screens after sunset.
'Our findings, together with evidence from other studies, suggest that reduction of nighttime light exposure should be considered as one of the potential strategies for preventing heart disease by clinicians and policy makers,' said Professor Qi.
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