Text Messaging: A Tool to Increase Compliance with Physical Activity Interventions?

Background: A need exists to identify effective approaches to increase compliance with physical activity interventions conducted in community settings.

Purpose: To use accelerometry to analyze the effects of bi-weekly, theoretically based motivational text messages on premenopausal women’s compliance to a walking intervention.

Methods: Premenopausal women (n=52, 37.2 ± 6.2 years, 80.8% Caucasian) wore ActiGraph model GT3x+ accelerometers during waking hours for an 8-week intervention, during which women were asked to walk at least 150 minutes each week at a moderate pace in bouts ≥ 10 minutes duration. During weeks 3, 5, and 7 of the intervention each woman received three motivational text messages per week from one of three categories: self-efficacy, social support, or increasing knowledge about benefits of physical activity. At the conclusion of the intervention, every subject had received text messages from all three categories in random order. To increase compliance during the intervention, two $25 gift cards were offered: the first for obtaining 150 minutes of moderate-intensity walking in 6 out of 8 weeks and the second for completing the intervention with a weekly average greater than 150 minutes of moderate-intensity walking.

Results: During the 8-week intervention, participants averaged 151.4 ± 64.2 weekly minutes of walking. In comparison to weeks with no text messaging, average walking duration was higher during weeks when self-efficacy and social support text messages were sent, although differences were not statistically significant [self-efficacy (+6.8 ± 55.3 min/wk, p=0.38), social support (+15.9 ± 58.5 min/wk, p=0.06), and increasing knowledge (-3.2 ± 54.1 min/wk, p=0.67)].

Conclusions: These results suggest that text messages related to social support may be more effective than messages which focus on self-efficacy or the health benefits of physical activity during community-based interventions. Future research should continue to explore the efficacy of different types and doses of motivational text messaging in promoting compliance with physical activity intervention studies, preferably in studies without concurrent financial incentives.

Grant Funding: NHLBI-1R21HL113742-01