Objective: To test the hypothesis that physical fitness is associated with more successful cognitive aging.
Methods: Surviving participants (N = 460) of the Scottish Mental Survey of 1932 were tested on the same general cognitive test at age 11 and 79 years. Measures of grip strength, 6-meter walk time, and lung function (forced expiratory volume from the lungs in 1 second [FEV1]) were assessed at age 79 years.
Results: A latent physical fitness trait, derived by principal components analysis of the three fitness measures, was significantly associated with successful cognitive aging. Cognitive score at age 11, sex, social class, and APOE-epsilon4 genotype were included as covariables. Higher childhood IQ was associated with better lung function in old age.
Conclusions: Physical fitness is associated with cognitive reserve. Intervention studies aimed at making older people fitter are good candidates to improve cognitive aging.