Forget 8 Hours – Scientists Discover Ideal Amount of Sleep in Middle & Old Age

Researchers from the University of Cambridge and Fudan University say seven hours is the ideal amount of sleep for people in their middle age and upwards, with too little or too much sleep associated with poorer cognitive performance and mental health.

Sleep plays an important role in enabling cognitive function and maintaining good psychological health. It also helps keep the brain healthy by removing waste products.

As we get older, we often see alterations in our sleep patterns, including difficulty falling asleep and staying asleep, and decreased quantity and quality of sleep. 

It is thought that these sleep disturbances may contribute to cognitive decline and psychiatric disorders in the aging population. 

In research published on April 28, 2022, in the scientific journal Nature Aging, scientists from the UK and China examined data from nearly 500,000 adults aged 38-73 years from the UK Biobank. 

Participants were asked about their sleeping patterns, mental health, and well-being, and took part in a series of cognitive tests. 

By analyzing the data, the team found that both insufficient and excessive sleep duration were associated with impaired cognitive performance, such as processing speed, visual attention, memory, and problem-solving skills.

Seven hours of sleep per night was the optimal amount of sleep for cognitive performance, but also for good mental health, with people experiencing more symptoms of anxiety and depression and worse overall wellbeing if they reported sleeping for longer or shorter durations.

The researchers say one possible reason for the association between insufficient sleep and cognitive decline may be due to the disruption of slow-wave – ‘deep’ – sleep.