Introduction: Hypertension is associated with increased risk for cognitive decline. Lifestyle behaviors such as moderate physical activity (MPA) and adequate sleep duration may mitigate this decline, though limited research exists. The aim of the study was to examine the joint association of MPA and sleep duration on cognitive function by hypertension status.
Methods: Adults (n=2976, ≥60yrs) from the 2011-2014 National Health and Nutrition Examination Survey (NHANES) were assessed for their habitual sleep duration (<7, 7-8.9, ≥9hr), self-reported participation in regular MPA (yes/no), reported physician-diagnosed hypertension (yes/no), and cognitive function (Digit Symbol Substitution Test [DSST]; Animal Fluency test). Weighted linear regression analyses were conducted to assess joint association of sleep duration and MPA on cognitive function, and test the modifying effect of hypertension status (alpha level set at 0.1) after adjustment for demographics.
Results: See Table. There were significant main effects for combined MPA and sleep duration on DSST (Wald F(5,28)=5.33, p=.001) and Animal Fluency (Wald F(5,28)=2.58, p=.05). Participants who did not engage in MPA regardless of sleep duration had significantly worse cognitive function compared to participants who engaged in MPA and obtained 7-8.9hr sleep. There was a significant interaction between MPA-sleep duration groups and hypertension status on DSST (Wald F(5,28)=2.42, p=.06), but not on Animal Fluency. Stratified analyses indicated among individuals with hypertension the buffering effect of MPA regardless of sleep duration was maintained, but not for individuals without hypertension.
Conclusions: In a sample of adults, regular MPA predicted better cognitive outcomes regardless of sleep duration. Among individuals with hypertension regular MPA regardless of sleep duration was significantly associated with better executive function, but no such association was found among individuals without hypertension.