The Impact of a Structured, Supervised Exercise Program on Daily Step Count in Sedentary Older Adults With and Without HIV

Background: People with HIV (PWH) may have lower daily activity levels compared with persons without HIV. We sought to determine the impact of initiating a supervised exercise program on the daily step count of sedentary PWH and uninfected controls. Methods: PWH and controls, aged 50-75, were enrolled in a 24-week supervised exercise program. All individuals were given a pedometer and instructed in regular use. A linear mixed model taking into account random effects was used to model daily step count. Results: Of 69 participants that began the study, 55 completed and 38 (21 PWH, 17 controls) had complete pedometer data. Baseline daily step count on nonsupervised exercise day was (estimated geometric mean, 95% confidence interval) 3543 (1306 to 9099) for PWH and 4182 (1632 to 10,187) for controls. Both groups increased daily steps on supervised [43% (20 to 69)%,P< 0.001] but not unsupervised exercise days [-12% (-24 to 1)%,P= 0.071]. Compared with controls, PWH had 26% [(-47 to 4)%,P= 0.08] fewer daily steps on days with supervised exercise and 35% [-53 to -10)%,P= 0.011] fewer daily steps on days without supervised exercise. Higher body mass index (per 1 unit) and smoking were associated with fewer daily steps [-5% (-9 to -1)%; -49% (-67 to -23)%;P <= 0.012]. Days with precipitation [-8% (-13 to -3)%,P= 0.002] or below freezing [-10% [-15 to -4)%,P< 0.001] were associated with fewer steps. Conclusion: Supervised exercise increased daily step counts in sedentary individuals, but at the expense of fewer steps on nonsupervised exercise days.