A new study reveals that poor sleep is associated with a variety of health consequences in seniors, such as stroke and dementia, Tech Times reports.

A group of Canadian researchers suggests that sleep fragmentation leads to changes in the brain that can only be observed in autopsies.

The study was published in the journal Stroke on Thursday, Jan. 14.

Sleep fragmentation is marked by waking episodes several times during the night.

The experts found that the more severe the sleep fragmentation, the higher is the risk of small brain arteries to harden. A person's risk of brain tissue death due to little oxygen in small strokes also increases as sleep fragmentation becomes worse.

"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," study author Dr. Andrew Lim, a neurologist and scientist at Sunnybrook Health Sciences Center in Toronto, said in a statement, as reported by Live Science.

For the study, the researchers studied the autopsied brains of 315 subjects, who had an average age of 90 years old. The participants underwent one week of sleep quality evaluation before they died.

The researchers noted that 29 percent of the subjects had a stroke and 61 percent suffered from moderate-to-severe damage of brain blood vessels.

The researchers also found that the average waking times in all the participants were seven times in an hour, but some had additional waking episodes during that period.

The study showed that those with the highest degree of sleep fragmentation were 27 percent more at risk to have hardened brain arteries.

Andrew Lim said that it was possible for the repeated waking episodes to increase blood pressure, which in turn could damage the blood vessels.

Lim, however, said that the study findings do not offer a cause-and-effect relationship between sleep and stroke.

"At this point in time we don't have hard evidence that treating sleep fragmentation is going to make a big difference," he said, as reported by Reuters.