A new study has found that higher exposure to artificial light at night may increase the risk of heart disease.
The research, led by scientists from Massachusetts General Hospital and Harvard Medical School, showed that people who lived in areas with more nighttime light had more brain stress, inflamed blood vessels, and a higher risk of serious heart problems.
Artificial light at night, such as from streetlights and indoor electronics, is nearly impossible to avoid in modern cities. But until now, we didn’t fully understand how this light pollution affects heart health.
In this study, researchers combined satellite images of nighttime light with advanced brain and heart scans to explore the connection.
All 466 participants in the study had no known heart disease or cancer and received a PET/CT scan at Massachusetts General Hospital between 2005 and 2008. The scan helps doctors see how the brain and blood vessels are functioning.
By using satellite data, the team also measured how much artificial light each person was exposed to at home.
The results were clear. People who lived in brighter areas at night had higher levels of brain stress activity and more signs of blood vessel inflammation.
These changes are early warning signs for future heart problems. Over the 10-year follow-up period, 17% of participants experienced major heart events such as heart attacks or strokes.
The study found that even small increases in nighttime light exposure led to a much higher risk of heart disease. The risk was about 35% higher over five years and 22% higher over 10 years for every standard increase in light exposure.
These results remained true even after accounting for other risk factors like age, income, and exposure to noise pollution.
Living in areas with other stressors, like heavy traffic noise or lower income neighborhoods, made the effects of nighttime light even worse.
Researchers believe this is because the brain responds to nighttime light as a form of stress, activating signals that trigger inflammation in the arteries. Over time, this can lead to hardened arteries and increase the risk of heart attack or stroke.
The study also supports a recent scientific statement from the American Heart Association about the importance of circadian health. Too much artificial light can confuse the body’s internal clock, reduce melatonin, delay sleep, and raise heart disease risk.
Doctors suggest a few ways to reduce nighttime light exposure: cities can use better streetlights or motion sensors, and people can avoid using screens before bed and keep bedrooms dark. These simple steps may help protect the heart.
Experts say this research is an important step in understanding how light pollution can harm health.
Although the study cannot prove that nighttime light directly causes heart disease, the strong link between the two shows that more attention is needed. Larger studies in more diverse groups are planned to confirm these results and test solutions.
If you care about heart disease, please read studies that herbal supplements could harm your heart rhythm, and how eating eggs can help reduce heart disease risk.
For more health information, please see recent studies that apple juice could benefit your heart health, and results showing yogurt may help lower the death risks in heart disease.
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