TORONTO, Jan. 15 (UPI) -- Fragmented sleep patterns are associated with damage to seniors' brains that increases their risk for stroke, according to a new study.
Researchers at the University of Toronto found fragmented sleep -- sleep that is interrupted by repeated awakenings -- is linked to higher rates of arteriosclerosis in the brain and a more brain tissue being deprived of oxygen, both of which can lead to stroke
"The forms of brain injury that we observed are important because they may not only contribute to the risk of stroke but also to chronic progressive cognitive and motor impairment," said Dr. Andrew Lim, an assistant professor of neurology at the University of Toronto, in a press release.
For the study, published in Stroke, researchers autopsied the brains of 315 people around age 90 whose sleep had been monitored for at least one full week around-the-clock for quality, as well as to calculate circadian rhythms.
Overall, 61 percent of the brains had signs of moderate to severe blood vessel damage and 29 of the people's brains showed signs of stroke. Participants with greater sleep fragmentation were 27 percent more likely and to have severe arteriosclerosis in their brains and for each additional two reawakenings per hour of sleep had a 30 percent increase in risk for visible signs of oxygen deprivation.
"However, there are several ways to view these findings: sleep fragmentation may impair the circulation of blood to the brain, poor circulation of blood to the brain may cause sleep fragmentation, or both may be caused by another underlying risk factor," he said.