Medscape Medical News reported that a recent study—the largest of its kind—analyzed light exposure data from nearly 90,000 people, totaling around 13 million hours of recordings. After a follow-up period of 8 to 10 years, researchers compared these data with records of cardiovascular disease incidence.
اضافة اعلان
The study, titled “Nighttime Light Exposure and Cardiovascular Disease Prevalence,” was published in JAMA Network Open. Based on data collected from approximately 89,000 participants, the findings showed that people who sleep in illuminated rooms face a 30% to 50% higher risk of developing heart disease compared with those who sleep in darkness.
Frank Scheer, PhD, Director of the Medical Chronobiology Program at Brigham and Women’s Hospital in Boston and a co-author of the study, said:
“In many other areas, we need stronger evidence because of their complexity and multiple pros and cons. But when it comes to nighttime light exposure, there is no harm in keeping the room dark, using only dim light when necessary to safely get out of bed.”
Increased Risk of Heart Disease
The study also found that individuals who sleep under bright lights at night are at significantly higher risk of cardiovascular conditions: 56% higher risk of heart failure, 47% higher risk of heart attack, and about 30% higher risk of coronary artery disease, atrial fibrillation, or stroke, compared with those who sleep in the dark. These associations remained even after accounting for other risk factors such as diet, physical activity, smoking, and genetic factors.
The researchers noted that the body’s biological clock is most sensitive to light between midnight and 6 a.m., and that exposure to light during this period—especially bright light—may independently increase the risk of cardiovascular disease, regardless of known risk factors like smoking, diet, and physical activity. They emphasized that modern lifestyles increase the likelihood of circadian rhythm disruption, making attention to nighttime light exposure particularly important.
According to The Harvard Gazette, coverage also indicates that nighttime light exposure is linked to an increased risk of cardiovascular disease due to its impact on the body’s circadian rhythm, even after adjusting for traditional risk factors such as smoking, diet, and physical activity.
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