Physical exercise and cognitive function across the life span: Results of a nationwide population-based study

Objectives: To examine cross-sectional and longitudinal associations between physical exercise and cognitive function across different age groups in a nationwide population-based sample of adults aged 18-79 years in Germany. Design: Cross-sectional/prospective. Methods: Cognitive function was assessed in the mental health module of the German Health Interview and Examination Survey for Adults (DEGS1-MH, 2009-2012, n = 3535), using a comprehensive neuropsychological test battery. Cognitive domain scores for executive function and memory were derived from confirmatory factor analysis. Regular physical exercise in the last three months was assessed by self-report and defined as no exercise, <2 and >= 2 h (hours) of exercise per week. A subgroup of DEGS1-MH participants who previously participated in the German National Health Interview and Examination Survey 1998 (GNHIES98, 1997-1999, n = 1624) enabled longitudinal analyses with a mean follow-up of 12.4 years. Results: Compared to no exercise, more weekly physical exercise was associated with better executive function in cross-sectional (<2 h: beta = 0.12; >= 2 h: beta=0.17; all p < 0.001) and longitudinal analyses (<2 h: beta=0.14, p < 0.001; >= 2h: beta = 0.15, p = 0.001) using linear regression models adjusted for age, sex, education, smoking, alcohol consumption, fruit and vegetable consumption and obesity. Slightly weaker associations were found for memory in cross-sectional (<2 h: beta = 0.08, p= 0.009; >= 2 h: beta= 0.08, p= 0.026) and longitudinal analysis (<2h: beta=0.09, p= 0.036; >= 2h: beta= 0.08, p = 0.114). There was no evidence of interaction between physical exercise and age. Conclusions: Higher levels of physical exercise were associated with better executive function and memory in cross-sectional and longitudinal analyses with no evidence for differential effects by age. (C) 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.