Using Time-Varying Effect Modeling to Examine the Association Between Cardiorespiratory Fitness and Global Cognition...

PurposeResearch demonstrates that cardiorespiratory fitness (CRF) mitigates age-related cognitive decline, but its specific effects across different stages of aging remain unclear. This study aimed to examine the association between CRF and global cognition in older adults, identifying the age ranges during which cognitive differences between older adults with higher and lower CRF levels were most pronounced.DesignCross-sectional.SettingData from the National Health and Nutrition Examination Survey 2011-2014.SampleA total of 2311 U.S. older adults aged 60 to 79 years.MeasuresCRF was estimated using a validated non-exercise regression equation, and participants were categorized into above- and below-median CRF groups. Global cognition was assessed using composite z-scores derived from 3 cognitive tests: CERAD Word Learning subtest, Animal Fluency Test, and Digit Symbol Substitution Test.AnalysisWeighted time-varying effect modeling was employed to examine age-related trends in the association between CRF and global cognition throughout late adulthood. Separate analyses were conducted for older adults with higher and lower CRF levels to explore differences in cognitive trajectories between these groups.ResultsParticipants with higher CRF demonstrated significantly better global cognition than those with lower CRF, particularly between the ages of 61 and 66. The largest difference was observed at age 62, where individuals with higher CRF had a mean composite score of 0.40 (95% CI = [0.27, 0.53]), compared to 0.03 (95% CI = [-0.10, 0.16]) for those with lower CRF.ConclusionPromoting improvements in CRF during key aging periods may serve as an effective strategy to delay age-related cognitive decline.