an older man with his eyes closedSleep’s effects on human health are far-reaching. A new study from Singapore identifies a relationship between sleep duration and cognitive decline in older adults. Using a longitudinal study, the researchers observed that age-related structural changes happen in the brain for adults who sleep less, aging the brain more rapidly. Sleep problems are common in older adults. The findings highlight the need for individuals to maintain healthy sleep habits as they age.

The researchers used data from the Singapore Longitudinal Aging Brain Study. The cohort they evaluated consisted of 66 Chinese adults over age 55. The adults’ brain volume was measured using an MRI and their cognitive skills using tests. The researchers used questionnaires to determine how well and how much the participants slept. They also measured blood levels of a particularly sensitive protein as an indicator of inflammation. Two years after this initial evaluation, the cohort participated in a second round of MRI scans and cognitive testing.

In the adults who slept fewer hours, there was evidence of faster brain shrinkage and of decline in cognitive performance, both hallmarks of an aging brain. For each hour less of sleep, the decline in cognitive performance increased by 0.67 percent. The quality of sleep was not linked to cognitive decline or brain volume; neither was inflammation. Lead study author Dr. June Lo, researcher with Duke-NUS Graduate Medical School in Singapore explains “Among older adults, sleeping less will increase the rate their brain ages and speed up the decline in their cognitive functions.”

Although the findings connect sleep and the brain’s aging processes, the research team does not know why sleep duration has these effects. In any case, the findings underscore the need for regular sleep and good sleep hygiene.

This research is published in the journal Sleep.

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