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Sleeping 7 to 8 hours produces best cognitive performance
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Sleeping between 7 and 8 hours a night led to better cognitive function than sleeping more or less than that amount, according to findings recently published in Sleep.
“Most people will at some point experience not getting enough sleep over a period of days, weeks or months. However, the effects of this kind of everyday sleep restriction on high-level cognitive abilities — such as the ability to store and recall information in memory, solve problems, and communicate — remain poorly understood,” Conor J. Wild, PhD, a research associate at The Brain and Mind Institute, Western University, in Ontario, Canada, and colleagues wrote.
Researchers used the internet to conduct a worldwide survey of respondent’s sleep habits. They analyzed data from 10,886 participants, of whom 6,797 were female. The mean age of all participants was 41.7 years.
Wild and colleagues found that the optimal amount of sleep for reasoning ability was 7.16 hours (95% CI, 6.78-7.74), for verbal ability, 7.44 hours (95% CI, 6.92-8.43), and for overall ability, 7.38 hours (95% CI, 7.027.91). Results also showed that sleeping 1.18 hours more than usual was associated with the best overall cognitive performance. Conversely, the lack of sleep in those who slept less than the usual, or 2.76 hours more than usual was associated with lower cognitive performance.
“Importantly, not all tests and cognitive domains were equally affected by the amount of sleep: participants’ reasoning and verbal abilities were observed to have a similar and reliable inverted-U shaped relationship with the number of hours slept, whereas this pattern was significantly different for [short-term memory],” researchers wrote.
“In fact, the evidence favored the null hypothesis that there was no relationship between short-term memory performance and reported hours of sleep. This dissociation suggests that regular sleep patterns impact only some higher-order cognitive processes, like the ability to identify complex patterns and manipulate information to solve problems, but has a lesser effect on basic memory processes,” they continued.
Wild and colleagues recommended that future research ascertain how day-to-day sleep patterns and deviations from those patterns impact high-level cognitive functioning among the general population. – by Janel Miller
Disclosures: Healio Family Medicine was unable to determine the authors’ relevant financial disclosures prior to publication.