This news may keep you up at night.
New research from Harvard University has found a link between evening light exposure and an increased risk of heart disease. Moreover, the authors claim that even modest amounts of light at night can have serious, long-term consequences.
In the small study, brain imaging and satellite measurements were used to draw a connection between nighttime light exposure and cardiovascular risk.
The team tied greater exposure to artificial light at night to increased stress activity in the brain, inflammation in the arteries and higher odds of 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,” said study senior author Dr. Shady Abohashem, head of cardiac PET/CT imaging trials at Massachusetts General Hospital and an instructor at Harvard Medical School.
“Light pollution is very common; however, we don’t know much about how it affects the heart.”
Abohashem and his team conducted a review of data from 466 healthy adults with a median age of 55. All participants underwent a PET/CT scan, and the amount of nighttime light in their homes was measured.
Participants were scanned between 2005 and 2008. During a 10-year follow-up, 17% had major heart problems.
Participants exposed to more artificial light at night had higher brain stress activity, blood vessel inflammation and a greater risk of major heart events.
The greater the exposure, the higher the risk, with each standard deviation rise in light exposure correlating to a 35% and 22% increased risk of heart disease over five- and 10-year follow-up periods.
“We found a nearly linear relationship between nighttime light and heart disease: the more night-light exposure, the higher the risk. Even modest increases in nighttime light were linked with higher brain and artery stress,” said Abohashem.
He explained that when the brain perceives stress, it can trigger an immune response that leads to inflammation in blood vessels.
“Over time, this process can contribute to hardening of the arteries and increase the risk of heart attack and stroke,” he added.
This increased risk persisted even after accounting for traditional risk factors, such as noise pollution and socioeconomic status.
Risk was highest among participants living in low-income and high-traffic neighborhoods.
Researchers are hopeful that their results will convince community leaders that reducing exposure to excessive artificial light at night is a public health concern.
By identifying the risk, interventions can be implemented to minimize unnecessary outdoor lighting, shield streetlights and/or utilize motion-sensitive lights.
“This research indicates that light pollution is more than just an annoyance; it could also increase the risk of heart disease,” Abohashem said.
“We hope clinicians and policymakers will consider nighttime light exposure when developing prevention strategies.”
While they explore interventions that reduce nighttime light and ways these strategies might improve heart health, the study authors recommend folks keep their bedrooms dark and avoid screens before bed.
Experts also suggest using blackout curtains or an eye mask to block harmful light.
What’s more, your heart isn’t the only thing that takes a hit from harmful light.
Previous research established that exposure to bright outside lights at night could increase your odds of developing Alzheimer’s disease more than other risk factors.
Artificial light at night can disrupt the body’s 24-hour biological clock and ruin sleep. Sleep deprivation and insomnia are associated with cognitive decline.
For seniors, Alzheimer’s prevalence had stronger ties to light pollution than risk factors such as alcohol abuse, chronic kidney disease, depression and obesity.
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