Scientists have dispelled the myth that we need 8 hours of sleep

A team of researchers from the universities of Cambridge, the United Kingdom, Fudan and China, found that seven hours of sleep a day is probably the ideal time for middle-aged people and adults in general.

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According to the study, published in the journal Nature Aging, seven hours of sleep are optimal for good cognitive skills and good mental health.

The researchers studied data from nearly 500,000 people between the ages of 38 and 73. They found that both insufficient and excessive sleep were linked to cognitive performance and poorer mental health.

Study participants provided data on their sleep habits and answered questions about their well-being and mental health. In addition, they completed a series of tasks that measured their processing speed, visual attention, memory and problem-solving skills. And those who slept seven hours had better performance in all tasks.

The authors of the study open a parenthesis: 94% of the participants were white. Therefore, it is not certain that the results are valid for people of color or for people from other ethnic groups or cultural communities.

Another important factor is persistence. People with insignificant deviations in their sleep patterns over long periods of time, who observed the seven hours of sleep, showed the best results.

Sleep disorders and the risk of dementia

“A good night’s sleep is important at all stages of life, but this is especially true as we age.” This is the opinion of Barbara Sahakian, a professor at the University of Cambridge and co-author of the study. Scientists believe that lack of sleep probably impedes the brain’s cleansing process of toxins. They also claim that sleep disturbance can also affect cognitive abilities.

When deep sleep is disturbed, it affects memory consolidation and can lead to amyloid buildup. Amyloid is a protein that, if not functioning properly, can cause deposits in the cerebral vessels characteristic of some forms of dementia.

Insufficient or too long sleep can be a risk factor for cognitive decline in old age.

“Although we cannot state categorically that too little or too much sleep is responsible for cognitive problems, our analysis seems to support this thesis,” says Jianfeng Feng, a brain researcher and professor at Fudan University. “But the reasons why older people get worse sleep seem to be complex and are influenced by genetics and the structure of our brain.”

Sleep duration and brain structure

The results of the study also suggest that sleep duration may be related to differences in the structure of some regions of the brain, such as the hippocampus, considered the center of memory and learning, and the prefrontal cortex, responsible for conscious movements.

The risk of developing Alzheimer’s disease and dementia, diseases of old age associated with cognitive impairment, is related to sleep duration. Therefore, experts believe that future research in this area will be very important.

“Finding ways to improve sleep in the elderly can be key to promoting good mental health and well-being, thus avoiding cognitive decline, especially in patients with mental disorders and dementia,” says Barbara Sahakyan.

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