Posted on Jul 24, 2014, 6 a.m.
Men and women ages 50 and older who get six to nine hours of sleep a night think better than those sleeping fewer or more hours.
A number of published small-scale studies in the United States, Western Europe and Japan suggest that sleep of sufficient duration and quality help to maintain cognitive skills with aging. A University of Oregon-led study finds that middle-aged or older men and women who get six to nine hours of sleep a night think better than those sleeping fewer or more hours. Theresa E. Gildner and colleagues leveraged data collected in the first wave of the Study on global AGEing and adult health (SAGE), focusing on 30,000 subjects ages 50 years and older, residing in China, Ghana, India, Mexico, the Russian Federation and South Africa. Data analysis revealed that men reported higher sleep quality than women in all six nations, with men and women in Mexico reporting the highest. Women reported longer sleep durations than men in all countries except Russia and Mexico. Men and women in South Africa slept longer than in any other country. The least sleep hours for both sexes occurred in India. Individuals sleeping less than six hours and more than nine hours had significantly lower cognitive scores compared to those in the intermediate group. Writing that: “This study documented positive correlations between cognitive scores and sleep quality, and between cognitive … scores and intermediate sleep duration,” the study authors submit that: “These findings are clinically important given the growing rates of dementia and aging populations globally.”
Theresa E. Gildner; Melissa A. Liebert; Paul Kowal; Somnath Chatterji; J. Josh Snodgrass. “Associations between Sleep Duration, Sleep Quality, and Cognitive Test Performance among Older Adults from Six Middle Income Countries: Results from the Study on Global Ageing and Adult Health (SAGE).” Journal of Clinical Sleep Medicine, Volume 10 No. 6, 613-621.