Background: The goals of this study were to examine 1) longitudinal trajectories of energy expenditure from recreational physical activity (PA) in postmenopausal women, 2) whether women who belong to different PA trajectories engage in different types of PA, and 3) whether baseline sociodemographic, health, psychosocial, and lifestyle characteristics predict membership in PA trajectories.
Methods: Women from the Women's Health Initiative Observational Study with baseline PA data (n = 92,629) were included. Physical activity, measured via self-report 6 times over 8 years, was converted to MET hr/wk for analysis. Latent growth curve mixture models and latent profile models were used to analyze longitudinal PA trajectories and cross-sectional PA composition, respectively.
Results: Three distinct, stable PA trajectories (highly, moderately, and minimally active) were identified with nearly 75% of the women classified as minimally active (≤ 8 MET-hr/wk). The majority of women who were at least moderately active engaged in a balanced combination of walking, moderate, and vigorous PA. Sociodemographic characteristics such as income, education, and past vigorous PA were predictive of PA trajectory, as were some health status indicators (eg, body mass index), but not health related quality of life.
Conclusions: Self-reported PA is largely stable across nearly a decade of follow-up in postmenopausal women.