Objective To investigate the impact of activity frequency on the self-care ability of older adults in China, providing a reference for developing active aging strategies aligned with their activity patterns.

Methods Data were drawn from the 2021 Chinese Longitudinal Healthy Longevity Survey (CLHLS) covering 14 022 older adults aged ≥ 65 years in 27 provinces (autonomous regions and municipalities). Multivariate ordinal logistic regression models were employed to analyze the associations between activity frequency and two functional outcomes: activities of daily living (ADL) and instrumental activities of daily living (IADL).

Results Among the 14 022 participants, 9 474 (67.6%), 1 037 (7.4%), and 3 511 (25.0%) showed the ADL status of full independence, requiring partial assistance, and full dependence, respectively; 3 803 (27.1%), 2 104 (15.0%), and 8 115 (57.9%) exhibited the IADL status of full independence, requiring partial assistance, and full dependence, respectively. The activity frequency was low, moderate, and high in 2 830 (20.2%), 143 (1.0%), and 11 049 (78.8%) participants, respectively. After adjustment for sex, age, children′s financial support, marital status, residence, income adequacy, and pension insurance, multivariate ordinal logistic regression analysis revealed that compared with the low-frequency group, the moderate-frequency group had reduced risks of ADL impairment (OR = 0.309, 95%CI: 0.218–0.437) and IADL impairment (OR = 0.175, 95%CI: 0.110–0.280). Furthermore, compared with the low-frequency group, the high-frequency group had decreased risks of ADL impairment (OR = 0.142, 95%CI: 0.129–0.156) and IADL impairment (OR = 0.082, 95%CI: 0.067–0.100).

Conclusions Increased activity frequency is associated with a reduced risk of ADL and IADL impairment among older adults in China, promoting greater independence.