New study reveals perfect amount of sleep for middle-aged brains

Sleep, Shakespeare informs us, is a remedy that “relieves the weary laborer and heals hurt minds”.

Now scientists at the University of Cambridge have found that the perfect dose of sleep is seven hours for people wanting to keep their minds healthy in middle age and beyond.

Any more or any less is linked to poor mental performance, upending current NHS advice to get between seven and nine hours.

Researchers examined data from nearly half a million British adults, aged between 38 and 73 years, who took part in the UK Biobank project – a study that monitored sleeping patternsmental health and wellbeing, as well as cognitive performance.

They found that both insufficient and excessive sleep were associated with slower processing speed as well as poorer visual attention, memory and problem-solving skills.

Seven hours was also 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 longer or shorter periods of time.

Professor Barbara Sahakian, of the Department of Psychiatry at Cambridge, one of the study’s authors, said: “Getting a good night’s sleep is important at all stages of life, but particularly as we age.

“Finding ways to improve sleep for older people could be crucial to helping them maintain good mental health and wellbeing and avoiding cognitive decline, particularly for patients with psychiatric disorders and dementias.”

Researchers said one possible reason for insufficient sleep triggering cognitive decline could be a lack of slow-wave – “deep” – sleep, which plays an important role in consolidating memories.