Turns out it’s your annoying friend who insists on closing all the blinds on the plane and covering all the glowing electronics in the bedroom so she can sleep in complete darkness somewhere. New research debunks a well-established theory linking nighttime light to adverse health effects.
The first analysis set to be presented at the American Heart Association’s 2025 scientific conference, starting on Friday, suggests that the state of darkness while we sleep plays an important role in our overall health. The results link more light at night, also known as healthy night light pollution, with higher symptoms of brain stress, inflamed blood vessels, and a greater risk of cardiovascular disease – a broad term for various heart problems.
“We know that environmental factors, such as wind and air pollution and noise, can lead to heart disease by affecting our nerves and constricting blood vessels.
Night light for night food at home
In a virtual study, Abohashemi and his colleagues reviewed the health data of 466 adults who had been caused by positron emission tomography / 2008 to identify massachusetts Boston signals between the brain and evidence of arterial inflammation. They also investigated seniors’ exposure to artificial nighttime light in their homes with the 2016 World Atlas of Night Sky Light 2016.
The researchers found that people who got high amounts of late night sleep had higher brain stress activity, inflammation of blood vessels, and a greater chance of developing heart disease. Apparently, the risk of heart problems increased among the participants living in areas with additional stressors such as loud traffic noise or low income of the neighborhood. By the end of 2018, 17% of adults had experienced significant heart problems.
“We found a consistent relationship between the middle of the night and heart disease: The more light exposure at night, the greater the risk. The association remained even after the researchers adjusted for known cardiovascular risk factors and other social and environmental stressors.
“When the brain senses pressure, it activates signals that can trigger an immune response and constrict blood vessels,” he added. “Over time, this process can contribute to hardening of the arteries and increase the risk of heart attack and stroke.”
Put the phone down
So what can we do about it? Cities can reduce unnecessary outdoor lighting, and people can reduce nighttime light before going to bed, according to Abohashem. That includes screenshots, which means nothing is visible on tiktok before snapping.
“We know too much exposure to light made for many nights can damage your health, especially increasing the risk of heart disease. “This study is one of the investigations of several possible causes, how our brain responds to stress. This response appears to play a major role in coordinating the artificial light at night.”
However, this study has some limitations, according to the statement. For example, participants were drawn from a single hospital system, so the group may not be heterogeneous, and the results may not reflect the broader population. In addition, due to the nature of the observational study, it cannot be proven that the associations are causal.
“We want to expand this work to a larger, larger population, to test interventions that reduce light at night, and test how reducing the reduction in time reduces heart health,” said Ahahashemi.
