VANCOUVER -- A new study is showing just how important a good night's sleep is for overall health.

The research, published in Nature Communications late last month, found the risk of dementia is 30 per cent higher among middle aged people who got less than six hours of sleep per night. 

Dr. Najib Ayas, associate professor of critical care medicine at UBC, told CTV Morning Live Tuesday that it's only been in the last several years that the importance of sleep has been recognized.

"I think that before sleep was usually considered a luxury. But I think over the last 10 or 15 years, it's becoming increasingly recognized that sleep is part of a healthy lifestyle," Ayas said.

The study, published on April 20, looked at about 8,000 people from the age of 50 and followed them for 25 years.

"What they found was that those individuals who reported sleeping six or less hours per night had about a 20 to 30 per cent increased chance of having dementia over the course of 25 years," Ayas said.

Researchers don't necessarily know why more sleep reduces the likelihood of getting dementia, Ayas said, but there are several possibilities.

"It's been shown that reduced sleep is associated with a variety of adverse physiologic abnormalities," he said, giving increased inflammation and blood pressure as examples.

"We do know that some cases of dementia may be related to these vascular causes."

Ayas explained sleep is important to clearing some toxins from the brain and that the buildup of those toxins may lead to neurodegenerative diseases, like dementia.

One of the issues, Ayas said, is that adults tend to get less sleep as they get older, even though they shouldn't be. Ayas said that it's not just a risk of dementia individuals should be concerned with.

"What we know is individuals who sleep six hours or less do seem to be at increased risk of obesity, cardiovascular disease, dementia and diabetes," he said. "Once you reach about seven to eight hours, that could be the optimum amount of sleep in order to preserve long-term health."

But some people believe it takes more sleep than that – a little more than eight hours – to preserve cognitive function, he said.

"I think one of the things that needs to be done is to prioritize sleep," Ayas said.