Abstract 38: Prospective Study of Midlife Sedentary Behavior, Physical Activity, and Cognitive Function: The CARDIA Study

Introduction: Evidence suggests moderate to vigorous intensity physical activity (MVPA) has beneficial effects on various domains of cognitive function; however, less than half of adults meet MVPA guidelines. Alternate approaches, such as reducing sedentary behavior (SED) with concurrent increases in light-intensity physical activity (LPA) may resonate more strongly with the adult population. Objective: To determine if accelerometer measured SED, LPA, and MVPA at ages 38-50 years is prospectively associated with measures of cognitive function. Methods: We studied 1,842 Black and White men and women enrolled in CARDIA who participated in the year 20 (2005-06) and year 25 (2010-11) and/or year 30 (2015-16) exams. SED, LPA, and MVPA were measured by the ActiGraph 7164 accelerometer at year 20. Cognitive function tests at the year 25 and 30 exams included the Rey Auditory Verbal Learning Test (RAVLT, memory), Digit Symbol Substitution Test (DSST, processing speed), and Stroop Test (executive function). Compositional isotemporal substitution analysis examined associations of SED, LPA, and MVPA at year 20 with repeated measures (unstructured covariance) of the cognitive function raw test scores at years 25 and 30. Results: In men, substituting 30 minutes of SED with 30 minutes of LPA was associated with a decrease in the RAVLT (-0.05) and DSST (-0.76), and increase in Stroop (0.45) scores, indicating worse performance (see Table ). Substituting SED or LPA with MVPA was associated with an increase in RAVLT (0.15, 0.20) and DSST (1.21, 2.00), and decrease in Stroop (-0.68, -1.17) scores, respectively, indicating better performance. In women, who had higher cognitive function scores than men, substituting SED or LPA with MVPA was associated with worse performance on the Stroop test (0.70, 0.63), contrary to our hypothesis. Conclusions: Statistical substitution of time from lower-intensity activities (SED or LPA) with MVPA, but not SED with LPA, resulted in better cognitive performance in men, but not women, over 10 years.