Home Health Warning to anyone who sleeps with blinds open – it may increase risk of stroke or heart attacks by 40%, study suggests

Warning to anyone who sleeps with blinds open – it may increase risk of stroke or heart attacks by 40%, study suggests

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Scientists suggested that bright lights were disrupting people's natural sleep-wake cycles, causing many people to sleep less than the recommended seven hours a night (file image)

Sleeping with the blinds open in cities could increase the risk of stroke by up to 43 percent, a study suggests.

Researchers in China made the discovery after comparing data from thousands of people living in city centers or suburbs, which have much less light pollution.

They suggested that bright lights entering homes at night suppressed the release of the sleep hormone melatonin and disrupted the body’s natural sleep-wake cycle.

This was leading to people sleeping less than the recommended seven hours a night, they said, increasing the risk of high blood pressure and type 2 diabetes, which are known to be risk factors for stroke.

Scientists suggested that bright lights were disrupting people's natural sleep-wake cycles, causing many people to sleep less than the recommended seven hours a night (file image)

Scientists suggested that bright lights were disrupting people’s natural sleep-wake cycles, causing many people to sleep less than the recommended seven hours a night (file image)

Dr Jain-Bing Wang, a public health expert who contributed to the paper, said: “Our study suggests that higher levels of exposure to outdoor artificial light at night may be a risk factor for cerebrovascular disease.”

“Therefore, we advise people, especially those living in urban areas, to consider reducing that exposure to protect themselves from its potential harmful effects.”

Many people are keeping their blinds open at night amid a new wellness trend encouraging people to “wake up with the sun”.

But scientists warn that around 80 percent of the world’s population already lives in areas with light pollution, which could make them have difficulty sleeping.

Using the Bortle Dark Sky Scale, which rates the darkness of the sky from one to nine, scientists say the average moonless night has a measurement of one, or very little light in the sky.

For comparison, major cities like New York have a measurement of nine, suggesting high levels of light pollution.

For the article, published today in the magazine StrokeThe scientists recruited 28,300 people from the Chinese port city of Ningbo, about 120 miles south of Shanghai.

The participants had an average age of 62 years and had no history of cerebrovascular disease, such as stroke and aneurysms.

Each was tracked for six years, from 2015 to 2021, and scientists recorded cases of stroke or other cerebrovascular disease through hospital medical records.

They detected 1,278 cases in total, of which 900 were strokes.

For the analysis, satellite images were used to estimate the light pollution suffered by each patient during the night.

The results were adjusted for age, sex, and income to suggest the risk of cerebrovascular disease from exposure to light at night.

The researchers wrote in the paper: “Exposure (to bright light at night) could cause the body’s circadian rhythm to suppress melatonin secretion.”

“This could lead to changes in biological indicators, including elevated levels of triglycerides…blood pressure and blood glucose, which are triggers for the onset of cerebrovascular diseases.”

Dr. Wang added: “Despite significant progress in reducing traditional cardiovascular risk factors, such as smoking, obesity and type 2 diabetes, it is important to consider environmental factors in our efforts to reduce global burden of cardiovascular diseases.

Limitations of the article included that there was no data on participants’ exposure to indoor light or whether they used blackout curtains.

The research was also partly carried out on the Covid pandemic, which may have affected people’s risk of disease through lifestyle changes.

The CDC recommends that everyone get between seven and nine hours of sleep each night.

The study also investigated the risk of cerebrovascular disease from air pollution.

It found that those living in areas with the highest levels of PM10 (a small compound released by car exhaust) had up to a 50 percent increased risk of cerebrovascular disease compared to those exposed to the lowest levels. .

Those exposed to the highest levels of PM2.5 (a smaller substance also released from cars) had a 41 percent higher risk.

And those exposed to nitrogen oxide, released by cars and industrial areas, had a 31 percent higher risk.

The researchers said there was no link between air pollution and light pollution and the risk of cerebrovascular disease.

Explaining the increased risk of air pollution in the article, they added: “An elevated risk of hemorrhagic stroke can be achieved by causing arterial vasoconstriction, elevated blood pressure, and increased susceptibility to cerebral vascular rupture by triggering endothelial dysfunction.”

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