The association between sensor-based assessments of daily physical activity patterns and physical fitness in older adults: a systematic review and meta-analysis

Background: This study aimed to investigate the association between sensor-based assessment of daily physical activity patterns and physical fitness among older adults by meta-analyses of relevant studies. Methods: A systematic search was conducted across six databases (PubMed, CINAHL by EBSCOhost, Web of Science, PsycInfo by ProQuest, Embase, and Scopus) from inception until January 18, 2025. Manual searches of reference lists and Google Scholar were also performed, utilizing predefined keywords to identify observational studies with bivariate association analyses. Joanna Briggs Institute Critical Appraisal Checklist for Cross-Sectional Studies was employed to assess study quality. The association analyses were further categorized based on the characteristics of daily activity (sedentary, light, moderate-to-vigorous) and physical fitness (e.g., grip strength, knee muscle strength, leg power, walking endurance, mobility function, and gait speed). Results: Thirteen cross-sectional studies were included in the meta-analyses. On average, older adults spent 78% of their day sedentary, 15% in light-intensity activity, and 7% in moderate-to-vigorous activity. Sedentary behavior was linked to lower physical fitness (to), while moderate-to-vigorous activity was linked to better fitness (to 0.43); light-intensity activity showed only weak and selective associations with better mobility function and gait speed (to 0.26). Conclusion: This review shows that while older adults spend much of their day sedentary, both moderate-to-vigorous and light-intensity physical activity are linked to better physical fitness. Promoting light-intensity activities may be a practical strategy to support mobility and independence, especially for those unable to meet higher activity guidelines. However, recommendations should remain cautious, as the evidence supporting an association between light-intensity physical activity and physical fitness is currently weak. PROSPERO registration: The protocol of this systematic review was registered on PROSPERO (Registration number: CRD42023471302).