The effect of less sleep on cognitive functioning has been discussed for many years. Experts could not find out exactly if fewer sleep hours cause dementia or if it is an effect of dementia. But a recent study suggests that people who sleep for fewer hours in their 50s and 60s are more likely to suffer from dementia during their old ages.
The Risk Of Dementia Increases With Fewer Sleeping Hours In Mid-Adulthood
The research is a long-duration study conducted for 25 years on 8,000 people in Britain. The study began with people when they aged 50 years. The research found that people who consistently had six or fewer hours of sleep each night were 30 percent more vulnerable to the diagnosis of dementia than those who had normal sleep of seven hours. People with a normal sleep rate were to report dementia three decades later. This research is now a part of the journal Nature Communications.
Changes in brain activity occur 15 to 20 years before people complain about memory loss and thinking problems. These changes include proteins related to Alzheimer’s getting accumulated in the brain. Sleep patterns accompanying such brain changes can act as an indicator of dementia. However, neurologist Dr. Erik Musiek suggests that the question of what comes first, the diagnosis or the brain conditions, remains unresolved.
The current findings, according to Erik, may help in solving the riddle to some extent, especially if the data was gathered from people before they had any changes in the brain activity that are associated with Alzheimer’s.
Similar findings were obtained from a study conducted in the 1980s. This study had 7,959 British civil servants as participants whose sleep pattern was recorded from 1985 to 2016. The results found that 521 participants who slept less were diagnosed with dementia in their late 70s.
The current study aimed at clarifying the relationship between sleep and dementia by separating people with mental disorders such as depression diagnosed before the participants were 65 years old. And the study found that people with normal mental health conditions but short sleep patterns are at a higher risk of dementia, said Dr. Séverine Sabia, the lead of the research study and an epidemiologist at the French public-health research center called Inserm. While the research found a correlation between sleep and dementia, no relationship was found between gender and dementia.
According to Pamela Lutsey, an epidemiology professor at the University of Minnesota, the study reports suggesting an association between short sleep and dementia can help in preventing the disease through improved sleep hours. But this research, like several other similar types of research, lacked evidence as it is based on self-reports.
The sleep duration of participants was measured with accelerometers and compared with the reports provided by the participants. But the process began only when they were 69 years old. According to a professor of old age psychiatry at University College London, Robert Howard, self-reporting studies pose such threats to data validation. Robert is also one of the experts who submitted comments on the recent study published in the Nature Communications journal.
However, some theories support the association between sleep rate and dementia. For instance, one theory holds that long waking hours mean long periods of activation of the neurons which, in turn, facilitate the production of amyloid. Another theory states that sleep helps in clearing the extra protein that flows in the brain. So, sleep deprivation may result in excess protein buildups.
While theories are indicative of a relationship between sleep and dementia, researchers find providing practical evidence challenging. And though the recent study shows the connection between short sleep and dementia, especially in middle adulthood, experts will require more data to conclude.