Dose-response relationship between physical activity and sarcopenia in peritoneal dialysis patients

Physical activity (PA) is of great importance for peritoneal dialysis (PD) patients with sarcopenia. However, the optimal PA dose for sarcopenia in PD patients remains unclear. This study adopted a cross-sectional design and enrolled PD patients from two large general hospitals in China between March 2023 and February 2025. Sarcopenia was diagnosed in accordance with the 2019 criteria of the Asian Working Group for Sarcopenia. The Chinese Low Physical Activity Questionnaire was used to assess PA levels. Restricted cubic spline (RCS) models were applied to examine the dose-response relationships of total PA consumption, total walking time, leisure walking time, light physical activity time, and inactive time with sarcopenia and its three parameters in PD patients. A total of 881 participants were included in the final analysis. Non-linear dose-response relationships were observed between total PA consumption and the prevalence of sarcopenia (overall p < 0.05, non-linear p < 0.05), as well as the five-repetition sit-to-stand (5-STS) (overall p < 0.01, non-linear p < 0.05). Total PA consumption was associated with handgrip strength, but no significant non-linear relationship was detected (overall p < 0.05, non-linear p > 0.05). No significant association was found between PA consumption and skeletal muscle index (overall p > 0.05, non-linear p > 0.05). A protective effect against sarcopenia was observed when PA consumption exceeded 33 MET-h/week, and its protective effect on 5-STS tended to plateau after reaching 43 MET-h/week. These findings indicate that there may be an optimal range of PA for simultaneously reducing sarcopenia risk and improving physical function in PD patients.