A recent study published in the *Journal of the American Medical Association* (JAMA) indicates that excessive exposure to artificial light at night may significantly elevate the risk of heart disease and breast cancer, with estimates suggesting an increase of up to 50%. This research, led by Dr. Jonathan Cedernaes from Uppsala University, analyzed data from approximately 89,000 participants over a one-week period from 2013 to 2016, followed by a comprehensive follow-up around eight years later.
The findings reveal a concerning association between high levels of nighttime artificial light and increased risks of various cardiovascular conditions, including coronary heart disease, stroke, atrial fibrillation, myocardial infarction, and heart failure. Notably, these elevated risks persisted even after accounting for several factors such as sleep duration, sleep efficiency, physical activity, and seasonal variations in light exposure.
Researchers have long recognized that light emitted from devices like cellphones and televisions can adversely affect sleep quality. However, this study expands on that understanding, highlighting the detrimental effects of other sources of artificial light during nighttime.
Daylight Exposure and Heart Health
Conversely, the research indicates that individuals exposed to higher levels of natural light during the day experience lower risks of cardiovascular diseases. Dr. Cedernaes emphasized the complexity of light’s impact on individual health. He noted, “Just as all light is not uniform, neither are we as individuals. Indeed, the light intensity needed to significantly suppress evening melatonin secretion is higher following greater daytime light exposure and can differ by several 10-fold across individuals.”
The implications of this study suggest that reducing unnecessary bright lighting at night could be beneficial in lowering cardiovascular risks. Optimizing exposure to natural light throughout the day may also play a crucial role in enhancing heart health.
As awareness grows about the potential health impacts of artificial light, this research serves as a reminder of the importance of being mindful of our nighttime environments. By making small adjustments to lighting at home and promoting greater daytime light exposure, individuals may contribute to better long-term health outcomes.
