According to research published in PLOS ONE by researchers at the University of Warwick, sleep problems are associated with worse memory and executive function in older people. Analysis of sleep and cognitive data from nearly 4,000 men and 5,000 women who took part in the English Longitudinal Study of Ageing (ELSA) was conducted in a study funded by the Economic and Social Research Council (ESRC). Respondents reported on the quality and amount of sleep over a month-long period. The findings of the study indicate that there is indeed an association between both quality and duration of sleep and brain function, which changes with age.
In adults between the ages of 50 and 64, short sleep (less than 6 hours a night) and long sleep (more than 8 hours a night) were associated with lower brain function scores. On the other hand, among adults older than 65, lower brain function scores were only seen in long sleepers. 6-8 hours of sleep every night is essential for optimum brain function among younger adults, results which are consistent with the previous research of the team, which showed that 6-8 hours of sleep per night was optimal for physical health, such as the lowest risk of developing hypertension, diabetes, heart disease, stroke and obesity. Interestingly enough, however, in younger pre-retirement-aged adults, sleep quality had no significant association with brain function scores. However, in older adults, there was a significant relationship between sleep quality and observed scores.
Sleep is important for good health and mental wellbeing, making the optimization of sleep at an older age essential to delay the decline in brain function usually seen with age. It could even slow or prevent the rapid decline that typically leads to dementia. Dr. Michelle A Miller, a leader in the study, concludes that if poor sleep causes future cognitive decline, then non-pharmacological improvements in sleep could provide and alternative low-cost and more accessible Public Health intervention, to delay or slow the rate of cognitive decline.