FEEL like you're getting less sleep as you get older? You're not alone.
New research from University of California, Berkeley suggests ageing adults may be losing their ability to have deep, restorative sleep.
Research co-author Matthew Walker said while sleep changes with ageing, sleep may also explain ageing itself.
"Every one of the major diseases that are killing us in first-world nations - from diabetes to obesity to Alzheimer's disease to cancer - all of those things now have strong causal links to a lack of sleep. And all of those diseases significantly increase in likelihood the older that we get, especially dementia," Professor Walker said.
The sleep loss appears to be linked to the slowly degrading neurons and circuits responsible for regulating sleep. This occurs as our brain ages and results in less non-rapid-eye-moment (REM) sleep.
"The evidence seems to favour one side - old adults do not have a reduced sleep need, but instead, an impaired ability to generate sleep," Professor Walker said. "The elderly, therefore, suffer from an unmet sleep need."
This non-REM deep sleep plays a key role in maintaining memory and cognition.
These changes appear to start in the mid 30s.
Co-author Bryce Mander said it was particularly dramatic in early middle age when the changes started to begin.
"There difference between young adults and middle aged adults is bigger than the difference between middle aged adults and older adults," Dr Mander said. "So there seems to be a pretty big change in middle age, which then continues as we get older."
Professor Walker said more attention needs to be paid to sleep disturbance as there currently aren't many treatment options.
The research was published in Neuron.
