Long-Term Usage of Breeze, a Gamified Breathing Training App, and Its Effect on Momentary Relaxation in People With Cancer: Cohort Study.

Background: People with cancer often experience stress. Digital health interventions can help individuals increase momentary relaxation. Breeze is a gamified breathing training that can be embedded into digital health interventions. Its effectiveness in controlled cross-sectional studies has been demonstrated. However, adherence to Breeze and its effect on momentary relaxation in longitudinal interventional studies has yet to be investigated. Objective: This study aimed to assess Breeze across 3 key dimensions: (1) its usage over time compared to other intervention components; (2) the accuracy with which users adhered to the guiding breathing pattern provided by Breeze; and (3) its effect on momentary relaxation, including the impact of the duration of the breathing session delivered by Breeze. Methods: Breeze was 1 of 7 relaxation techniques included in the CanRelax 2.0 app, designed specifically for individuals diagnosed with cancer. Participants could select any of the 7 techniques to promote momentary relaxation. The intervention was designed to last 10 weeks. However, participants were allowed to use the CanRelax 2.0 app after that period. Participants were adults diagnosed with cancer in the last 5 years recruited across Switzerland, Germany, and Austria. Adherence to the intended breathing pattern was measured using a Pearson correlation coefficient. Momentary relaxation was measured pre- and post-exercise using an 11-point visual analog scale. Statistical analyses included linear mixed effects models and calculations of effect sizes. We further analyzed the relationship between session duration and the magnitude of momentary relaxation and compared Breeze's efficacy and time efficiency to the other available techniques. Results: Of 279 participants, 118 (42.3%) used Breeze at least once. The 118 participants engaged in 754 breathing sessions with Breeze. Momentary relaxation was assessed and calculated for 249 (33.0%) Breeze sessions. The use of Breeze declined initially but remained stable even after 10 weeks. Participants followed the predefined breathing rates of Breeze (r=0.9). On average, a small effect (-0.42; P<.001; d=0.19) on momentary relaxation was observed, with 2-minute breathing sessions (-0.30; P=.02; d=0.13) showing a small effect, whereas a large effect (-1.53; P=.03; d=0.74) was observed for breathing sessions of 4 minutes or longer. Conclusions: This study demonstrates the potential of Breeze to alleviate acute stress in individuals with chronic conditions, such as cancer. By combining gamification with evidence-based breathing techniques, Breeze fosters sustained user engagement and momentary relaxation. Participants adhered well to the guided breathing. While even short breathing sessions of 2 minutes provided modest momentary relaxation, longer durations (≥4 min) were considerably more effective. Future research aims to assess the impact of Breeze on other populations and chronic conditions.