Using internet and mobile phone technology to deliver an automated physical activity program: Randomized controlled trial

Background: The Internet has potential as a medium for health behavior change programs, but no controlled studies have yet evaluated the impact of a fully automated physical activity intervention over several months with real-time objective feedback from a monitor. Objective: The aim was to evaluate the impact of a physical activity program based on the Internet and mobile phone technology provided to individuals for 9 weeks. Methods: A single-center, randomized, stratified controlled trial was conducted from September to December 2005 in Bedfordshire, United Kingdom, with 77 healthy adults whose mean age was 40.4 years (SD=7.6) and mean body mass index was 26.3 (SD=3.4). Participants were randomized to a test group that had access to an Internet and mobile phone-based physical activity program (n=47) or to a control group (n=30) that received no support. The test group received tailored solutions for perceived barriers, a schedule to plan weekly exercise sessions with mobile phone and email reminders, a message board to share their experiences with others, and feedback on their level of physical activity. Both groups were issued a wrist-worn accelerometer to monitor their level of physical activity; only the test group received real-time feedback via the Internet. The main outcome measures were accelerometer data and self-report of physical activity. Results: At the end of the study period, the test group reported a significantly greater increase over baseline than did the control group for perceived control (P <.001) and intention/expectation to exercise (P <.001). Intent-to-treat analyses of both the accelerometer data (P=.02) and leisure time self-report data (P=.03) found a higher level of moderate physical activity in the test group. The average increase (over the control group) in accelerometer-measured moderate physical activity was 2 h 18 min per week. The test group also lost more percent body fat than the control group (test group: -2.18, SD=0,59; control group: -0.17, SD=0.81; P=.04). Conclusions: A fully automated Internet and mobile phone-based motivation and action support system can significantly increase and maintain the level of physical activity in healthy adults.