Improving the Physical Activity of Breast Cancer Survivors Through Fitness Trackers

Introduction: Increasing physical activity among posttreatment breast cancer survivors is essential, as greater physical activity reduces the relative risk of cancer-specific mortality. This trial examines how a fitness tracker-based intervention changes the physical activity behaviour of inactive posttreatment breast cancer survivors. Methods: Seventeen physically inactive posttreatment breast cancer survivors participated in a randomised cross-over controlled trial. Participants underwent a 12-week intervention of a fitness tracker combined with a behavioural counselling and goal-setting session and 12 weeks of normal activity (control). The primary outcome was the change in physical activity assessed by accelerometry over seven days. Results: The intervention achieved a mean increase of 4.5 min/day of moderate-vigorous physical activity, representative of a small-moderate effect (d = 0.34). Changes in time spent as a proportion of the day in light physical activity (-8.3%) and in sedentary behaviour (7.9%), were both significantly different to baseline (t (16) = 3.522, p < 0.01; t (16) = -3.162, p < 0.01). Conclusion: Interindividual differences in the change of patterns of physical activity behaviour suggest that only for some, fitness trackers can achieve a change in the level of moderate-vigorous physical activity.