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The Association Between Extreme Sleep Duration and Cardiac Autonomic Control in Community-Dwelling Older Adults: The Yilan Study, Taiwan

Backgrounds
The aims of the present study were to determine the associations and sex-specific relationships between extreme sleep duration and cardiac autonomic control in a cohort of older individuals.


Methods
A community-based survey was conducted in Yilan City, Taiwan. Community-dwelling older adults aged ≥65 were randomly selected to participate. Extreme sleep durations were defined as either short sleep (≤5 hours) or long sleep (≥8 hours). Cardiac autonomic control was evaluated using the parameters of frequency-domain analysis of heart rate variability.


Results
Of 1,721 participants, 58.7% were female. In multiple logistic regression analyses, short sleep duration did not correlate with any of the unhealthier parameters of heart rate variability. In contrast, long sleep duration was associated with elevated risk for poor high-frequency values (odds ratio [OR]: 1.83, 95% confidence interval [CI]: 1.34-2.50) and the unfavorable low-frequency values (OR: 1.44, 95% CI: 1.05-1.97). When stratified by sex, the associations between extreme sleep duration and poor heart rate variability were more robust in males.


Conclusions
Poor cardiac autonomic control may underlie the link between extreme sleep duration and adverse health outcomes in older adults. A sex-specific relationship between poor cardiac autonomic function and extreme sleep duration also was found.