Abstract
BACKGROUND: Given that limited research has examined the relationships between lifestyle activities of varying intensities, including moderate-to-vigorous physical activity (MVPA), light physical activity (LPA), and sedentary behavior (SB), and dynapenia, which refers to an age-related decline in muscle function, this study aimed to investigate the longitudinal associations between MVPA, LPA, and SB and the risk of dynapenia among older adults in Taiwan. METHODS: This longitudinal study included older adults aged ≥ 65 years with independent mobility, recruited from the National Taiwan University Hospital. Baseline data were collected from September 2020 to December 2021 and follow-up data were collected until December 2022. Participants wore a tri-axial accelerometer (GT3X + ActiGraph) on the hip for seven consecutive days to evaluate baseline time spent of MVPA (≥ 2020 counts/min), LPA (100-2019 counts/min), and SB (< 100 counts/min). To confirm the dynapenia classification at baseline and follow-up, participants underwent standard assessments, including handgrip dynamometry for muscle strength, bioelectrical impedance analysis for muscle mass, and a 6-m walk test for physical performance. Adjusted binary logistic regression analyses were conducted to examine the association between lifestyle activities and dynapenia risks. RESULTS: Among 154 participants (mean age 80.3 ± 7.2 years; 53.9% women), 53.9% were classified as having dynapenia at baseline, compared to 55.2% at follow-up. Participants spent an average of 16.9 (± 26.6) min in MVPA, 249.5 (± 85.7) min in LPA, and 604.5 (± 76.4) min in SB daily. The longitudinal analysis results indicated that higher MVPA time was significantly associated with lower odds of dynapenia in both the unadjusted (odds ratio [OR] = 0.625, 95% confidence interval [CI]: 0.466-0.837) and fully adjusted models (OR = 0.578, 95% CI: 0.406-0.823). Each additional 10 min/day of MVPA was associated with 42.2% lower odds of dynapenia in the adjusted model. No significant prospective associations were observed between the LPA or SB time and dynapenia. CONCLUSION: This study provides longitudinal evidence that higher MVPA levels are significantly associated with a reduced dynapenia risks among community-dwelling older adults in Taiwan. These findings underscore the importance of promoting MVPA as a part of lifestyle interventions aimed at preserving muscle function and preventing dynapenia in older populations.