Night lighting increases the risk of developing cardiovascular diseases

Scientists suggest that disruption of the body’s natural circadian rhythms due to artificial lighting has a negative effect on heart function.

The biological mechanism behind this connection is explained by the fact that light plays a key role in regulating sleep and wakefulness. Disruption of natural cycles can lead to malfunctions in internal processes, including blood pressure and glucose metabolism.

“Light at night causes disruption of circadian rhythms, which is a known risk factor for cardiovascular disease,” note the authors of the study, which is currently under review and planned for publication in a scientific journal.

To study this relationship, the researchers analyzed data from 88,905 adults who wore wrist sensors to measure light levels for a week. Follow-up medical examinations were conducted over 9.5 years. Participants were divided into groups based on the amount of light they were exposed to at night.

The results showed that 10% of people exposed to the brightest nighttime lighting had a significantly higher risk of heart disease than those who slept in darkness. Possible problems included coronary heart disease, heart attack, heart failure, atrial fibrillation, and stroke.

The researchers took into account factors such as smoking, alcohol consumption, diet, sleep duration, physical activity, socioeconomic status, and genetic predisposition to more accurately determine the impact of nighttime light.

Although the study does not prove a direct causal relationship, the pattern identified is strong enough to consider nighttime light a risk factor. Scientists note that reducing its impact may be a simple and effective way to lower the likelihood of developing heart disease.

“The association between nighttime lighting and the risk of heart failure and coronary heart disease was more pronounced in women, and the effect of light on the risk of heart failure and atrial fibrillation was stronger in younger participants,” the authors write.

One possible explanation may be hypercoagulation — an increased tendency of blood to clot, which has previously been linked to circadian rhythm disruption. However, the exact mechanisms of this relationship require further study. Scientists hope that future studies covering longer observation periods and taking light sources into account will help to better understand its impact on heart health.

Today, many people leave their TVs or smartphones on in their bedrooms, which may exacerbate the problem. Surveys show that more than half of the US population falls asleep with the TV on.

“Avoiding light at night may be a useful strategy for reducing the risk of cardiovascular disease,” the researchers conclude.