Exposure to artificial light at night appears to trigger stress in the brain and inflammation in the arteries, raising heart disease risk. Researchers say even modest light increases could have long-term cardiovascular consequences.
Higher exposure to artificial light at night was associated with increased stress activity in the brain, inflammation in the arteries, and a greater risk of heart disease, according to a preliminary study presented recently at the American Heart Association’s Scientific Sessions 2025.
Why Artificial Light at Night Matters
Artificial light at night, often referred to as nighttime light pollution, is nearly unavoidable in modern urban environments, the researchers noted. In this first-of-its-kind investigation, scientists combined brain imaging with satellite data to identify a biological pathway that may connect nighttime light exposure to heart disease.
“We know that environmental factors, such as air and noise pollution, can lead to heart disease by affecting our nerves and blood vessels through stress. Light pollution is very common; however, we don’t know much about how it affects the heart,” said study senior author Shady Abohashem, M.D., M.P.H., head of cardiac PET/CT imaging trials at Massachusetts General Hospital and an instructor at Harvard Medical School in Boston.
How Researchers Measured Brain Stress and Artery Inflammation
All participants underwent the same Positron Emission Tomography/Computed Tomography (PET/CT) scan. The study included 450 adults who had no history of heart disease and no active cancer. “This is a routine imaging test at my hospital,” Abohashem said. “The CT portion provides detailed anatomy, while the PET portion reveals metabolic activity in tissues. Using both imaging techniques together allows for the measurement of brain stress activity and arterial inflammation in a single scan.”
