According to studies, persons in their middle years and older should get seven hours of sleep every night, with too little or too much sleep being linked to worse mental and cognitive functioning.
Sleep is crucial for sustaining psychological health and supporting cognitive function. It also helps the brain stay healthy by getting rid of trash. As we age, our sleep habits frequently change, and we experience issues with falling and staying asleep as well as decreasing quantity and quality of sleep. It is believed that these sleep abnormalities may be a factor in the ageing population’s cognitive decline and mental illnesses.
In a study that was just published in Nature Aging, researchers from the UK and China looked at information from over 500,000 persons in the UK Biobank who were between the ages of 38 and 73. A series of cognitive tests and questions regarding participants’ sleep habits and mental health and wellbeing were also administered. Nearly 40,000 research participants had genetic and brain imaging data accessible.
The team’s analysis of these data revealed that poor sleep quality and quantity were both linked to a decline in cognitive abilities including processing speed, visual attention, memory, and problem-solving abilities.
The best amount of sleep for both cognitive function and mental health was seven hours per night, with participants who reported sleeping for longer or shorter periods of time feeling worse overall and having more symptoms of worry and despair.
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The interruption of slow-wave sleep, sometimes known as “deep sleep,” may be one reason for the link between inadequate sleep and cognitive deterioration, according to the researchers. It has been demonstrated that disruption of this kind of sleep is closely related to memory consolidation and the accumulation of amyloid, a crucial protein that, when it misfolds, can result in the “tangles” in the brain that are indicative of some types of dementia. Additionally, a lack of sleep may make it harder for the brain to get rid of pollutants.
The research team also discovered a relationship between sleep duration and variations in the structure of brain areas related to cognitive processing and memory, with bigger alterations linked to greater or fewer than seven hours of sleep.
It was also crucial for cognitive function, excellent mental health, and overall wellness to get a constant seven hours of sleep every night. Previous research has demonstrated that irregular sleep patterns are linked to increased inflammation, suggesting that older persons are more susceptible to illnesses connected with ageing.
Professor Jianfeng Feng from Fudan University in China 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. But the reasons why older people have poorer sleep appear to be complex, influenced by a combination of our genetic makeup and the structure of our brains.”
Risk of excessive sleep duration
The results, according to the researchers, point to a possible risk factor for cognitive deterioration as people age: inadequate or excessive sleep duration. Previous research has suggested a connection between sleep length and the risk of dementia and Alzheimer’s disease, both of which include cognitive loss as a characteristic symptom.
Professor Barbara Sahakian from the Department of Psychiatry at the University of 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.”