Dose Response Walking Activity And Physical Function In Older Adults

Abstract

PURPOSE: To examine the dose-response relationship between walking activity and physical function in community-dwelling older adults. METHODS: The Wellness Works Program is an ongoing community-academic partnership providing free access to exercise facilities for Milwaukee County seniors. The present study evaluated 836 older adults who underwent an intake assessment including measures for general demographics and anthropometrics, physical activity (PA) and function assessments, prior to joining the program. PA was assessed by pedometer (Yamax SW-200) worn on the mid-thigh line of the right hip for 7 consecutive days. Function was evaluated by the Physical Functioning (PF) scale of the Medical Short-Form Outcomes questionnaire, and from the completion of a 6 minute walk test (6MWT). PA was averaged for the week and categorized into 4 groups (1=≤2500 [n=281], 2=2501-5000 [n=326], 3=5001-7500 [n=141], and 4=≥7501 steps/d [n=88]). PF and 6MWT distributions among PA groups were summarized with sample means and SD. ANOVA and general linear models were used for unadjusted and adjusted (for age and gender) group comparisons. RESULTS: The average age and body mass index for men was 68±9 yrs (n=334) and 30±6 kg/m2 (n=334) and for women was 67±8 yrs (n=491) and 31±7 kg/m2 (n=500). Overall, participants walked an average of 4022 step/d, reported a PF score of 71.7 % and walked 1097.5 ft on the 6MWT. Across PA groups, PF mean scores increased from 66.9±1.4% to 73.5±1.3% to 78.8±1.9% to 81.3±2.5% and 6MWT distance increased from 941.7±15.2 ft to 1154.1±14.0 ft to 1260.1±21.3 ft to 1294.0±26.8 ft. Both PF and 6MWT scores were statistically different across all PA groups, apart from groups 3 and 4. PA and ranks of PA groups were highly significant predictors (p<.0001) for both PF and 6MWT in unadjusted and adjusted for age and gender analyses. CONCLUSIONS: There was a dose-response relationship evident for both PF and 6MWT with increasing levels of PA, with the greatest benefit being seen between PA group 1 (≤2500 steps/d) and PA group 2 (2501-5000 step/d). Low levels of PA appear to be an important determinant of physical function in older adults. Efforts to increase walking behavior in this population are warranted to improve function. This work was Supported by a Career Development Award from the National Institute on Aging (K01AG025962).