Exercise advice by humans versus computers: Maintenance effects at 18 months

Objective: An automated telehealth counseling system, aimed at inactive midlife and older adults, was shown previously to achieve 12-month physical activity levels similar to those attained by human advisors. This investigation evaluated the sustained 18-month impacts of the automated advisor compared with human advisors. Methods: Following the end of the 12-month randomized, controlled trial, participants who had been randomized to either the human advisor (n = 73) or automated advisor (n = 75) arms were followed for an additional 6 months. During that period, human or automated advisorinitiated telephone contacts ceased and participants were encouraged to initiate contact with their advisor as deemed relevant. The primary outcome was moderate-to-vigorous physical activity (MVPA), measured using the Stanford Physical Activity Recall and validated during the major trial via accelerometry. Results: The two arms did not differ significantly in 18-month MVPA or the percentage of participants meeting national physical activity guidelines (ps >.50). No significant within-arm MVPA differences emerged between 12 and 18 months. Evaluation of the trajectory of physical activity change across the 18-month study period indicated that, for both arms, the greatest physical activity increases occurred during the first 6 months of intervention, followed by a relatively steady amount of physical activity across the remaining months. Conclusions: The results provide evidence that an automated telehealth advice system can maintain physical activity increases at a level similar to that achieved by human advisors through 18 months. Given the accelerated use of mobile phones in developing countries, as well as industrialized nations, automated telehealth systems merit further evaluation.