A randomized controlled trial of an automated exercise coach for older adults

Objectives: To compare the efficacy of a computer-based physical activity program (Embodied Conversational Agent-ECA) with that of a pedometer control condition in sedentary older adults.

Design: Single-blind block-randomized controlled trial stratified according to clinic site and health literacy status.

Setting: Three urban ambulatory care practices at Boston Medical Center between April 2009 and September 2011.

Participants: Older adults (N = 263; mean age 71.3; 61% female; 63% African American; 51% high school diploma or less).

Intervention: ECA participants were provided with portable tablet computers with touch screens to use for 2 months and were directed to connect their pedometers to the computer using a data cable and interact with a computer-animated virtual exercise coach daily to discuss walking and to set walking goals. Intervention participants were then given the opportunity to interact with the ECA in a kiosk in their clinic waiting room for the following 10 months. Control participants were given a control pedometer intervention that only tracked step counts for an equivalent period of time. Intervention participants were also provided with pedometers.

Measurements: The primary outcome was average daily step count for the 30 days before the 12-month interview. Secondary outcomes were average daily step count for the 30 days before the 2-month interview. Outcomes were also stratified according to health literacy level.

Results: ECA participants walked significantly more steps than control participants at 2 months (adjusted mean 4,041 vs 3,499 steps/day, P = .01), but this effect waned by 12 months (3,861 vs 3,383, P = .09). For participants with adequate health literacy, those in the ECA group walked significantly more than controls at both 2 months (P = .03) and 12 months (P = .02), while those with inadequate health literacy failed to show significant differences between treatment groups at either time point. Intervention participants were highly satisfied with the program.

Conclusion: An automated exercise promotion system deployed from outpatient clinics increased walking among older adults over the short-term. Effective methods for long-term maintenance of behavior change are needed.