Nighttime Artificial Light and Heart Health

A recent study conducted in Boston has linked high exposure to artificial light at night with increased brain stress activity, arterial inflammation, and a higher likelihood of heart disease. This study is an important step towards understanding the relationship between nighttime light pollution and cardiovascular health, suggesting that light pollution could be a modifiable environmental factor in communities with high nighttime lighting.

Night Light and Heart Health

A preliminary study presented at the American Heart Association Sessions 2025 showed a connection between increased artificial light at night and heightened brain stress signals, vascular inflammation, and an elevated risk of heart disease. These sessions, held in New Orleans, cover new developments, research, and updates in cardiovascular science.

Researchers described nighttime artificial light, also known as nighttime light pollution, as a nearly universal phenomenon in modern urban environments. This unique study combined brain imaging and satellite measurements to map a biological pathway that may link nighttime brightness with the risk of heart disease.

Key Findings: Increased Exposure, Higher Risk

The study found that individuals exposed to higher levels of artificial light at night exhibited higher brain stress activities, vascular inflammation, and an increased risk of major cardiac events. These risks increased by 35% and 22% over five and ten-year follow-up periods, respectively, for each increase in artificial light exposure.

These associations persisted even after accounting for other traditional factors such as noise pollution and socioeconomic status. Additionally, cardiac risks were higher among participants living in areas with additional social or environmental stressors.

Stress Pathways and Vascular Inflammation

Dr. Shadi Abu Hashim, the lead author of the study, explained that the relationship between night light and heart disease is almost linear: the greater the exposure to night light, the higher the risk. When the brain perceives stress, it triggers signals that can lead to an immune response and vascular inflammation, increasing the risk of heart attacks and strokes.

To mitigate the effects of artificial light at night, it is recommended to reduce unnecessary outdoor lighting and use motion-sensitive lights. Individuals can also minimize indoor nighttime lighting, keep rooms dark, and avoid screens before bedtime.

Conclusion

This study suggests that light pollution is not just a visual nuisance but may increase the risk of heart disease. Although the findings are still preliminary and require further research, they provide significant evidence of the link between light pollution and heart health. Researchers hope to expand the study to include larger and more diverse populations and test interventions that reduce nighttime light exposure. In conclusion, nighttime light exposure should be considered when developing health prevention strategies.