Dose-Response Relationship Between Physical Activity and Intrinsic Capacity Decline Among Hospitalised Older Patients

Intrinsic capacity (IC) serves as the foundation for functional performance in older adults, and its decline exerts a significant negative impact on their overall health status. However, the dose-response relationship between physical activity (PA) and IC decline is unclear. The objective of this study was to examine the dose-response relationship between PA and IC decline in hospitalised older adults.

This cross-sectional study was conducted from August 2024 to July 2025, with hospitalised older patients recruited from three tertiary hospitals in Gansu Province, China. Data were collected using a general information questionnaire, the IC Assessment Scale and the International Physical Activity Questionnaire-Short Form (IPAQ-SF). Binary logistic regression and restricted cubic spline (RCS) models were used to explore the association between PA and IC decline, adjusting for potential confounders.

The final analyses included a total of 534 hospitalised older patients. Using the low PA group as the reference, the moderate PA group was associated with a 66% lower likelihood of IC decline (OR = 0.34, 95% CI: 0.23-0.50), and the high PA group was associated with a 74% lower likelihood (OR = 0.26, 95% CI: 0.14-0.49). In the RCS analysis, a J-shaped nonlinear association was observed between PA levels and IC decline. Subgroup analyses by sex indicated that sex may serve as a potential moderator in the association between PA and IC decline.

This study revealed a J-shaped nonlinear association between PA and the likelihood of IC decline, with moderately higher PA levels associated with a lower likelihood of IC decline.