People who spend less time sleeping deeply could be at increased risk for dementia, according to a new study.

 

People tend to sleep more poorly as they age, and spend less time in deep sleep, which is also known as slow wave sleep. Slow wave sleep is important in processing new memories and remembering facts.

 

Honolulu-based researchers conducted a study on 167 Japanese Americans with an average age of 84. The subjects were given sleep tests and then followed until all of them had died.

 

The subjects had been classified in accordance with how much oxygen their brains had received during sleep. During slow wave sleep, the brain gets more oxygen. 

After their deaths, autopsies were performed to look for changes in their brains, such as abnormalities or a loss of brain cells that could indicate Alzheimer’s disease and Lewy body disease, which cause dementia.

 

The study found that the people with the lowest levels of oxygen in their brains were up to four times as likely to have the types of brain changes that are associated with developing dementia.

 

The research was published online in the journal Neurology.