Elderly people who sleep poorly and awaken frequently are more likely to have hardened blood vessels (arteriosclerosis) and oxygen-starved tissue known as infarcts in the brain, according to a study first published online in advance of the January issue of the American Heart Association’s journal Stroke.
Researchers examined autopsied brains of 315 people (average age 90; 70% women) who had undergone at least one full week of around-the-clock monitoring, from which sleep quality and circadian rhythms were measured. In all, 29% of the patients had suffered a stroke and 61% had signs of moderate to severe damage to blood vessels in the brain.
Scientists found that fragmented sleep could increase the risk of arteriosclerosis by 27%. (In this study, sleep was disrupted, on average, almost seven times each hour.) Moreover, for each additional two awakenings during one hour of sleep, researchers reported a 30% increase in the odds that people had visible signs of oxygen deprivation in their brain.
Sleep monitoring may be a way to identify seniors who may be at risk of stroke, according to Dr. Andrew Lim, lead investigator and an assistant professor of neurology at the University of Toronto, and a neurologist and scientist at Sunnybrook Health Sciences Center, also in Toronto.
The relationship between cardiovascular disease and fragmented sleep has been studied in the past, but this is the first research to take a detailed look at blood vessels from autopsied brains of seniors who had undergone sleep monitoring before death.