Seven hours of sleep is the sweet spot for better mental wellbeing
SLEEP, Shakespeare said, “relieves the weary labourer and heals hurt minds”.
Now scientists at the University of Cambridge have found the perfect dose is seven hours, to keep people’s minds healthy in middle age and beyond. More or less is linked to poor mental performance, upending NHS advice to get seven to nine hours.
Researchers examined data from almost half a million UK adults aged between 38 and 73 who took part in the UK Biobank project, which monitored sleep patterns, mental health and wellbeing, and cognitive performance.
They found insufficient and excessive sleep were linked to slower processing speed, poorer visual attention, memory and problem-solving skills.
Seven hours was found to be the sweet spot for good mental health, with people experiencing more anxiety and depression and worse overall wellbeing if they slept for more or less time.
Prof Barbara Sahakian, a study author and clinical neuropsychology professor, said: “Finding ways to improve sleep for older people could be crucial to help them maintain good mental health and wellbeing and avoid cognitive decline.”
The team said a possible reason for insufficient sleep triggering cognitive decline could be a lack of slow-wave sleep, or “deep” sleep, which is important for consolidating memories.
Problems with slow-wave sleep are linked to the build-up of the protein amyloid which can misfold, causing tangles in the brain characteristic of some forms of dementia. The correct amount is important, as sleep removes toxins to keep the brain healthy.
Prof Jianfeng Feng from Fudan University, China, a collaborator in the research, said: “While we can’t say conclusively that too little or too much sleep causes cognitive problems, our analysis looking at individuals over a longer period of time appears to support this idea.”
The research was published in the journal Nature Ageing.
‘Finding ways to improve sleep for older people could be crucial to help maintain good mental health’