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Night Light Linked to Heart Damage
10 Sep
Summary
- Higher nighttime light exposure correlates with thicker heart walls.
- Heart muscle shows reduced flexibility and signs of stress.
- Findings may explain links between light pollution and heart disease.
Recent research indicates a correlation between elevated nighttime light exposure and significant changes in the heart's structure and function. The study, involving over 11,000 participants from the UK Biobank, utilized wrist sensors to measure light exposure and cardiac MRI scans to assess heart health approximately three years later.
Individuals exposed to more than 3 lux of light at night displayed thicker left ventricular walls and diminished chamber size compared to those in near-total darkness. The heart muscle also showed reduced flexibility during each beat, presenting structural and functional alterations akin to those resulting from injury or increased workload.
While the study is observational and cannot confirm causation, researchers propose several biological mechanisms. Disruption of the circadian clock due to light at night may impact sleep, hormone production, and blood pressure, potentially increasing cardiovascular disease risk. Other factors like urban living and sleep habits were also considered.
Experts suggest that reducing unnecessary light exposure at night is a practical step for individuals. Simple measures include turning off lights, using blackout curtains, and covering electronic device LEDs. At a broader level, optimizing outdoor lighting design could mitigate light pollution's impact on public health.
