Nature sub-journal: 7 hours is the best sleep time for middle-aged and elderly people

Seven hours of sleep is the ideal sleep time for middle-aged and middle-aged adults, with too little or too little sleep leading to cognitive decline and worsening mental health, according to researchers from the University of Cambridge and Fudan University

Sleep plays an important role in achieving cognitive function and maintaining good mental health

In a study published today in the journal Nature Aging , scientists from the UK and China looked at data from almost half a million adults aged 38-73 from the UK Biobank

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

One possible reason for the link between sleep deprivation and cognitive decline is that slow-wave sleep, or "deep sleep," is disrupted, the researchers said

The team also found a link between sleep duration and structural differences in areas of the brain involved in cognitive processing and memory, with sleep durations greater or less than 7 hours also associated with greater changes

Sleeping 7 hours per night without too many fluctuations in duration is also important for cognitive performance and good mental health and well-being

Professor Jianfeng Feng from Fudan University in China said: "While we cannot be certain that too little or too much sleep can lead to cognitive problems, our long-term analysis of individuals seems to support this view

The findings suggest that insufficient or too much sleep may be a risk factor for cognitive decline in older adults, the researchers said

One of the study's authors, Professor Barbara Sahajian, from the University of Cambridge's Department of Psychiatry, said: "A good night's sleep is important at all stages of life, especially as we age

Provided by the University of Cambridge