Why a good night's sleep gets harder as you get older
It is a myth that people need less sleep as they get older - they just struggle to get it, new research suggests.
A review by the University of California found the ageing process restricts the ability to produce deep restorative sleep, leaving the middle-aged and older people sleep-deprived and at greater risk of illnesses, including Alzheimer's disease.
It is often said that people need less sleep after they hit middle age, with many older people rising earlier.
But the research found that in fact, the quality of sleep older people received was dramatically lower, with brain scans showing disrupted electrical patterns and changes which are associated with sleep deprivation. As the brain ages, the neurons and circuits in the area that regulate sleep slowly degrade, resulting in a decreased amount of deep sleep, experts said.
The lack of such non-REM (dreamless) sleep is associated with memory and cognition, and linked to conditions including Alzheimer's and cancer.
"Sleep changes with ageing, but it doesn't just change with ageing; it can also start to explain ageing itself," said co-author Professor Matthew Walker, who leads the sleep and neuroimaging laboratory at the University of California, Berkeley. The review examined whether older people needed less sleep, as had long been argued, or whether they were actually unable to generate sleep that they badly needed.
It concluded that sleep deprivation is a common side-effect of ageing.
"The evidence seems to favour one side - older adults do not have a reduced sleep need, but instead, an impaired ability to generate sleep," Prof Walker said.
Changes in sleep quality start as early as the mid-30s, problems were worse in men.
Those struggling with sleep problems should follow standard "sleep hygiene" advice, researchers said.
This included avoiding coffee from late afternoon, cutting out alcohol, and keeping a regular sleep diary.
Prof Walker added: "Every one of the major diseases that are killing us in first-world nations, from diabetes to obesity to Alzheimer's disease to cancer, have strong causal links to a lack of sleep." (© Daily Telegraph London)