Making Healthy Habits Stick: Extended Contact Interventions to Promote Long-Term Physical Activity in Cancer Survivors

Obesity, medical comorbidities, second primary cancers, poor quality of life and compromised physical functioning, disproportionately affect cancer survivors. There is strong evidence that physical activity (PA) has the potential to attenuate these differences in health risk. Yet, insufficient PA is more prevalent among cancer survivors and most do not meet PA guidelines. Efforts to increase PA longer term in cancer survivors have been modestly successful. The extant literature and our own preliminary data in cancer survivors shows that PA adoption is often followed by an attenuation of PA over time. These findings have led to a recent shift in thinking, specifically that the social cognitive theory constructs (e.g., self-efficacy) important for PA adoption play less of a role in PA maintenance while other theoretical constructs (e.g., habit) play a more important role in long-term behavior change. Conceivably, lack of success in promoting PA maintenance may also be due to few studies examining how well health behavior change interventions work in different circumstances. Thus, to advance PA maintenance science, we propose testing two potentially translatable PA maintenance promotion interventions (Short Message Service [SMS] and peer coach) in 260 physically inactive cancer survivors using a rigorous, randomized 2 x 2 factorial experimental design. Survivors will complete a 3-month PA adoption phase (i.e., efficacious theory-based PA behavior change program) prior to randomization to a PA maintenance promotion intervention or usual care. Our 6-month SMS and peer coach PA maintenance promotion interventions will be guided by the Multi-Process Action Control (M-PAC) framework which includes constructs which are understudied in cancer survivors yet hypothesized to be important for PA maintenance (e.g., habit). Assessments will occur at baseline (pre-PA adoption), 3 months (post-PA adoption; immediately prior to randomization), 9 months, and 15 months. Our specific aims are: 1) Determine effects of both PA maintenance interventions (SMS, peer coach) compared to usual care on PA maintenance (i.e., main effects and if either intervention effects differ in the presence of the other); 2) Identify theory-based mediators of PA maintenance; and 3) Identify social, behavioral, and psychological factors that moderate the relationships between the PA maintenance interventions and PA behavior at month 15.