Effects of a computer-based, telephone-counseling system on physical activity

Background: There is increasing interest in developing interventions to promote physical activity (PA) that do not involve face-to-face contact with health professionals. We developed a fully automated PA counseling system (telephone-linked communication, TLC-PA) that was delivered via telephone. Design: A randomized, controlled trial with 298 adult, sedentary members (mean age, 45.9 years; 72% women; 45% white; and 45% African American) of a multi-site medical practice. The comparison group (TLC-Eat) received all automated intervention promoting healthy eating, which was also delivered via telephone. Intervention: The TLC-PA promoted moderate-intensity PA (MI-PA) based on the transtheoretical model of behavior change and social cognitive theory. The system was available to participants for 6 months. Main Outcomes: Energy expenditure in MI-PA, proportion of participants who met recommendations for MI-PA, and motivational readiness for PA. Measures: Self-reports of PA behavior and motivational readiness at baseline, 3 months, and 6 months. Results: At 3 months, intention-to-treat analyses showed that the TLC-PA group was more likely to meet recommendations for MI- or vigorous-intensity PA (VI-PA) compared to the TLC-Eat group (TLC-PA=26% vs TLC-Eat=19.6%, p=0.04). Among study completers, TLC-PA subjects reported significantly higher daily kilocalorie energy expenditure in MI-PA (2.3 kcal/kg/d vs 2.0 kcal/kg/d, p=0.02); a larger proportion met, recommendations for MI- or VI-PA (31.2% vs 21.3%, p=0.02) and were in more advanced stages of motivational readiness than TLC-Eat subjects (TLC-PA=52.5% vs TLC-Eat=42.2%, p=0.04). Results were not maintained at 6 months. The proportion of TLC-PA users decreased significantly over the intervention period. Conclusions: A fully automated counseling system had positive short-term effects on PA among sedentary adults. Lack of maintenance of effects may be due to a decrease in the number of participants who continued to use the system.