Disrupted nightly sleep and clogged arteries tend to sneak up on us as we age. And while both disorders may seem unrelated, a new study helps explain why they are intertwined.
University of California sleep scientists have begun to reveal what it is about fragmented nightly sleep that leads to the fatty arterial plaque build-up known as atherosclerosis that can result in fatal heart disease.
“We’ve discovered that fragmented sleep is associated with a unique pathway – chronic circulating inflammation throughout the blood stream – which, in turn, is linked to higher amounts of plaques in coronary arteries,” said study senior author Professor Matthew Walker.
The findings reveal poor sleep as a key risk factor for cardiovascular disease.
“To the best of our knowledge, these data are the first to associate sleep fragmentation, inflammation and atherosclerosis in humans,” said study lead author Raphael Vallat.
Established risk factors for cardiovascular disease in humans include poor diet, lack of exercise, obesity, high blood pressure and smoking.
Using statistical modelling, the researchers analysed the diagnostic data of more than 1600 middle-aged and older adults using a national dataset known as the multi-ethnic study of atherosclerosis.
To isolate the effect of sleep quality on heart health, the study controlled for age, ethnicity, gender, body mass index, sleep disorders, blood pressure and high-risk behaviours such as smoking.
The researchers then tracked the results of the study participants, analysing their blood tests, their calcium scores that can gauge plaque build-up, as well as several different measures of sleep, including wristwatch-assessed sleep across a week and a night in a sleep laboratory that measured electrical brainwave signals.
The final outcome clearly linked disrupted sleep patterns to higher concentrations of circulating inflammatory factors and, specifically, of white blood cells known as monocytes and neutrophils, which are key players in atherosclerosis.
“In revealing this link with chronic inflammation, the findings suggest a missing middleman that is brokering the bad deal between fragmented sleep and the hardening of blood vessels,” Prof. Walker said.
The findings linking poor sleep to atherosclerosis via chronic inflammation have major public health implications, the researchers said.
With chronic inflammation shaping up to be a bridge connecting poor sleep to cardiovascular disease, it’s worth exploring its role in a plethora of other diseases where inflammation is known to be a possible factor, the researchers said.
“This link between fragmented sleep and chronic inflammation may not be limited to heart disease, but could include mental health and neurological disorders, such as major depression and Alzheimer’s disease,” Prof. Walker said. “These are new avenues we must now explore.”
Tips to improve sleep quality
1. maintain a regular sleep routine, going to bed and waking up at the same time each day
2. as part of a nightly wind-down routine, avoid viewing computer, smartphone and TV screens in the last hour before bedtime, and keep phones and other digital devices out of the bedroom
3. engage in some form of physical exercise during the day
4. get exposure to natural daylight, especially in the first half of the day
5. avoid stimulants, such as caffeine, and sedatives, such as alcohol, later in the day
6. if you can’t sleep, get out of bed and do a relaxing activity away from the bedroom, such as reading in dim light, and only return to bed when you’re sleepy
7. get screened for sleep apnoea if you are known to be a heavy snorer and/or feel excessively tired during the day.
8. consult your doctor if you are experiencing insomnia and inquire about cognitive behavioural therapy as a treatment.
Do you suffer from disrupted sleep? Have you ever tried to fix the problem? What works for you?
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Disclaimer: This article contains general information about health issues and is not advice. For health advice, consult your medical practitioner.