From crankiness to lack of energy, we all know the consequences of a poor night's sleep. But what happens when sleep problems become more commonplace and we find ourselves wide awake most nights?
According to a recent study, poor sleep in old age can make our brains age faster - potentially leading to health issues such as dementia and Alzheimer's Disease.
The study, run by Duke-NUS Graduate Medical School Singapore (Duke-NUS), examined the data of 66 older Chinese adults, from the Singapore-Longitudinal Ageing 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. Those who slept fewer hours showed evidence of faster ventricle enlargement and decline in cognitive performance.
"Our findings relate short sleep to a marker of brain ageing," said Dr June Lo, the lead author and a Duke-NUS Research Fellow.
"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," added Professor Michael Chee, senior author and Director of the Centre for Cognitive Neuroscience at Duke-NUS.
These findings, relevant in the context of Singapore's rapidly ageing society, pave the way for future work on sleep loss and its contribution to cognitive decline, including dementia.
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.
“Sleep is the single most important health behaviour we have," says Professor Russell Foster, chair of Circadian Neuroscience and head of the Sleep and Circadian Neuroscience Institute at the University of Oxford.
"It affects everything from our day-to-day functioning to our long-term physical and mental health."