The less sleep older adults get, the faster their brains age, according to a recent study Channel NewsAsia reported.

Researchers from Duke-Nus Graduate Medical School in Singapore found that older adults who sleep less than seven hours a day are more likely to develop neurogenerative disease such as Alzheimer's.

"Our findings relate short sleep to a marker of brain aging," Dr. June Lo, the lead author and a Duke-NUS Research Fellow, said in a statement.

For the study, researchers collected and analyzed data of 66 older Chinese adults aged 55 years and older from the Singapore-Longitudinal Aging Brain Study. Participants underwent structural MRI brain scans measuring brain volume and neuropsychological assessments testing cognitive function every two years. Additionally, their sleep duration was recorded through a questionnaire.

Researchers found that those who slept fewer hours showed evidence of faster ventricle enlargement and decline in cognitive performance.

"Work done elsewhere suggests that seven hours a day for adults seems to be the sweet spot for optimal performance on computer based cognitive tests. In coming years we hope to determine what's good for cardio-metabolic and long term brain health too," Professor Michael Chee, senior author and Director of the Centre for Cognitive Neuroscience at Duke-NUS, said in a statement.

Past research has examined the impact of sleep duration on cognitive functions in older adults. Though faster brain ventricle enlargement is a marker for cognitive decline and the development of neurodegenerative diseases such as Alzheimer's, the effects of sleep on this marker have never been measured.

Researchers said the findings are relevant in the context of Singapore's "rapidly ageing" society and may pave the way for future work on sleep loss and its contribution to cognitive decline, including dementia.