Association of Lifestyle Activities with Daily Physical Activity Timing in Community-Dwelling Older Adults: A longitudinal observational study

Background The timing of physical activity, particularly afternoon activity, is associated with positive health outcomes in older adults. It is plausible that the benefits of afternoon activity may partly reflect increased social activity among lifestyle activities. We tested the hypothesis that social activity specifically is associated with greater physical activity in the afternoon among lifestyle activities. Methods In this longitudinal observational study, 2,578 community-dwelling adults aged 65 years and older from the National Center for Geriatrics and Gerontology—Study of Geriatric Syndromes cohort completed a lifestyle activities questionnaire at baseline, which yielded scores in cognitive, physical, and social domains. Participants wore accelerometers for at least seven valid days (≥ 10 h/day), and mean steps were calculated for eight three‐hour spans over 24 hours. Correlation analyses were also conducted to explore relationships among the three lifestyle-activity domains. We applied function‐on‐scalar regression models to examine the association between each activity score and the timing of daily steps, adjusting for demographic, health, and behavioral covariates. Stratified analyses by age group, sex, and total daily step counts were conducted, along with a sensitivity analysis restricted to daytime hours. Results Among the 2,578 participants (mean age 70.7 years, 57% women), weak but positive correlations among cognitive, physical, and social activity scores were observed. Higher cognitive activity scores were associated with fewer steps in the early morning; physical activity scores were positively associated with steps from mid-morning to early afternoon; and social activity scores showed modest positive associations with steps throughout the day, especially in the afternoon. These patterns were consistent across age, sex, and daily-step-count groups, and they were also supported by the sensitivity analysis; however, associations between social activity and step counts were not statistically significant among men nor among adults aged over 75 years. Conclusions Associations between lifestyle activities and timing of daily steps vary by activity type and time of day: cognitive activities relate to fewer morning steps, physical activities relate to a morning peak, and social activities relate to sustainably more afternoon steps. These findings suggest that the previously reported association between afternoon physical activity and favorable health outcomes may partly stem from increased social activity.