Linking Physical Activity and Aerobic Fitness: Are We Active Because We Are Fit, or Are We Fit Because We Are Active?

The purpose of this study was to test the hypothesis that physical activity (PA), measured over a period of 23 years, is beneficial to aerobic fitness (VO₂max) in boys and girls (13–36 years) who were enrolled in the Amsterdam Growth and Health Longitudinal Study (AGAHLS). PA was measured using a standardized activity interview. VO₂max was assessed directly with a maximal running test on a treadmill. To assess the longitudinal relationship between PA and VO₂max, different longitudinal analyses were carried out over different age periods, correcting for various confounders such as lifestyle parameters, biological parameters, and initial VO₂max. Highly significant relationships (p < .05) were observed between PA and VO₂max in four of the five analyses. However, in an autoregression analysis, when current PA has been related to the future change in VO₂max, the results are not any more significant (p > .05). Analysis of the data of PA and VO₂max from the AGAHLS population does not fully support the hypothesis that PA affects VO₂max. [ABSTRACT FROM AUTHOR]