Comparing Human and AI Motivational Text Messages to Increase Physical Activity in Adults 40 and Older

What this Trial Is About

Researchers are evaluating the impact of different types of motivational text messages on the physical activity levels of adults aged 40 and older who currently engage in less than 90 minutes per week of moderate or higher intensity activity. The study aims to identify which motivational messages most effectively increase daily step counts during a 3-month precision text messaging intervention and to assess effects on automatic affective evaluations, habit strength, exercise identity, working memory capacity, and processing speed. Participants will receive up to four motivational text messages daily during a self-selected 12-hour window over three months. The intervention includes two phases a first month of randomly timed messages to gather baseline behavioral responses, followed by two months of precision-timed messages optimized based on individual responses. The study compares two groups one receiving previously tested motivational messages and another receiving newly created messages. Participants will also wear a Fitbit continuously for three months and are encouraged to continue for six months, along with wearing an activPAL monitor on the thigh for seven-day periods at baseline, three months, and six months. Throughout the study, participants complete three daily cognitive assessments on their smartphones during the seven-day monitoring periods at baseline, three months, and six months. They also set personal goals to increase daily steps during the first three months and complete questionnaires at baseline, three months, and six months. Researchers will measure daily step counts as the primary outcome and assess behavior change mechanisms and cognitive function as secondary outcomes. Participants are expected to keep study-related apps running in the background on their smartphones throughout the six-month protocol.

Motivating Activity Through Text Communications - Helping Adults Increase Movement