Less cognitive decline in older adults who get average amount of sleep, study says

Researchers concluded that there is a middle range, or “sweet spot,” for total sleep time,’ writes Matt Mathers

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Short and long sleepers suffer greater cognitive decline than those who get an average amount of sleep even when the effects of Alzheimer’s disease are taken into account, according to a new multi-year study of older adults.

A team of researchers at Washington University School of Medicine in St Louis tracked the cognitive functions in a large group of older adults over several years and analysed this against levels of Alzheimer’s-related proteins and measures of brain activity during sleep.

The researchers found a ‘U-shaped’ relationship between sleep and cognitive decline. Overall, cognitive scores declined for the groups that slept less than 4.5 (short sleepers) or more than 6.5 hours per night (long sleepers) while scores stayed stable for those in the middle of the range.