According to one study, 1 per cent reduction in deep sleep per year for people over the age of 60 results in a 27 per cent increased risk of dementia. The study also implies that improving or sustaining deep sleep, commonly known as slow-wave sleep, in later life may aid in the prevention of dementia.

Associate professor Matthew Pase of the Monash School of Psychological Sciences and the Turner Institute for Brain and Mental Health in Melbourne, Australia, conducted the study, which was published in JAMA Neurology.