Insomnia may trigger inflammation that leads to heart disease, research suggests.
Disturbed sleep has previously been linked to “furring” of the arteries, but it was unclear how.
Fragmented sleep was linked to higher levels of an immune-fighting protein that leads to inflammation.
This is then thought to cause calcium deposits to accumulate in the arteries, making them narrow and become blocked.
Oxygen-rich blood is then prevented from reaching the heart and brain, leading to heart attacks and strokes.
“Improving sleep may offer a novel way to reduce inflammation and thus reduce the risk of atherosclerosis,” said study author Professor Matthew Walker.
“These findings may help inform public health guidelines that seek to increase the continuity of sleep as a way to improve health and decrease the burden of heart disease on society.”
Heart disease is a leading cause of death in both the UK and US.
Insomnia is similarly prevalent, affecting around a third of Britons.
One in three Americans are also said to have the sleep disorder.
It is unclear if this disturbed shut eye will continue as officials continue to gain more control over the pandemic.
To learn more about the impact of insomnia, the Californian study’s volunteers wore wrist monitors that detected their movement for one week.
Blood tests then measured levels of the immune-fighting proteins neutrophils and monocytes, both drivers of inflammation.
Results – published in the journal PLOS Biology – linked fragmented sleep to higher levels of neutrophils, but not monocytes.
This in turn lead to calcium deposits accumulating in the arteries, known as atherosclerosis.
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This remained true after the scientists accounted for age, sex, ethnicity, body mass index, smoking and blood pressure.
Although unclear, insomnia may raise levels of the stress-hormone cortisol.
Cortisol may then interfere with the production of factors that limit neutrophil production.
The volunteers who reported poor sleep were not found to have higher levels of calcium in their arteries.
This suggests asking patients about their shut eye may not be a useful ways of assessing whether it puts them at risk of heart disease, said the scientists.