Barriers and enablers of adherence to high-intensity interval training among patients with cancer: a systematic review and meta-analysis

Objective Physical activity confers physical and psychosocial benefits for cancer patients and decreases morbidity and mortality, but adherence varies. High-intensity interval training (HIIT) is time-efficient and may improve adherence. Our aim was to determine barriers and enablers of adherence to HIIT in patients diagnosed with cancer. Design Systematic review and meta-analysis. Data source PubMed-MEDLINE, Scopus and Web of Science. Eligibility criteria Intervention studies including patients diagnosed with any type of cancer, who engaged in HIIT with or without co-intervention in any stage of treatment and have reported outcomes for adherence. Results Eight hundred articles were screened and 22 were included (n=807); 19 were included in the meta-analysis (n=755). Weighted adherence to HIIT was 88% (95% CI, 81% to 94%). None of the studies reported serious adverse events. Although being a woman and having breast cancer were associated with lower adherence (p<0.05), age was not (p=0.15). Adherence was significantly lower during the treatment phase in comparison with pre- and post-treatment phases, 83% versus 94% and 96%, respectively (p<0.001). Session time of more than 60 min, when unsupervised and combined with other interventions, was associated with decreased adherence (p<0.05). Conclusion Adherence to HIIT programmes among cancer patients varies and is improved when the intervention is supervised, of shorter duration, consists of solely HIIT and not in combination with other exercise and occurs during pre- and post-treatment phases. Strategies to improve adherence to HIIT in specific subpopulations may be needed to ensure all patients with cancer are provided optimal opportunities to reap the benefits associated with physical activity. PROSPERO registration CRD42023430180. All data relevant to the study are included in the article or uploaded as supplementary information.