How the Intensities of Physical Activities Shape the Health Trajectory of Multimorbid Older Adults

ObjectiveThis study examines healthy aging (HA) intercepts and slopes and how physical activity moderates their association with multimorbidity among older adults in the United States.MethodsData were drawn from the Health and Retirement Study, a representative survey between 2004 and 2020. Growth curve models were estimated for 1,238 retired individuals to assess how light, moderate, and vigorous physical activity moderated the relationship between multimorbidity and HA trajectories across three domains.ResultsHigher frequencies of physical activity were associated with moderated effects of multimorbidity on both baseline levels and rates of change in HA across domains. These associations were observed across moderate, light, and vigorous physical activity models, with patterns of favorable moderation. Additionally, between-individual variation was observed in HA trajectories, with higher baseline levels of HA being associated with slower decline.ConclusionPhysical activity offers a protective effect against multimorbidity-related decline, highlighting its importance for promoting healthy aging.