Physical health outcomes and step cadence improvements: a digital physical activity intervention in cancer survivors

Cancer survivors experience symptoms that can often be managed with moderate-to-vigorous physical activity. Most studies are short, small, and in-person, limiting scalability. This study evaluated a 12-month digital moderate-to-vigorous physical activity intervention and its impact on long-term physical health outcomes in a large sample of cancer survivors.

This 2-arm trial was embedded within the Cancer Prevention Study-3 prospective cohort study and included survivors with cancers associated with physical inactivity. Eligible participants were randomly assigned to a digital moderate-to-vigorous physical activity intervention or control group and completed 4 assessments (including surveys and accelerometry) across the 12-month intervention. Primary outcomes were total steps, step cadence (peak 1 minute and 30 minutes), 30-second sit-to-stand, self-reported mobility, walking pace, and pain. The primary analysis followed an intention-to-treat approach, with subgroup analyses by website engagement and among those with poor outcomes at baseline.

In total, 415 were randomly assigned (intervention: n = 286; control participants: n = 129), and 391 were included in the analysis. The intervention did not statistically significantly affect total steps, mobility, walk pace, or pain. However, website-adherent participants showed higher peak cadence (adherent: 125 steps per minute vs nonadherent or control participants: 121-122 steps per minute) and clinically meaningful improvement in sit-to-stand performance (average increase: 13-16, P < .001).

In intention-to-treat analyses, there were no statistically significant changes in most physical health outcomes. Among participants who adhered to the website protocol, the intervention was associated with improvements in cadence and 30-second sit-to-stand performance.

Our findings support the potential of scalable digital interventions to promote moderate-to-vigorous physical activity, with benefits more apparent among engaged users.