Effects of resistance training vs high intensity interval training on body composition, muscle strength, cardiorespiratory fitness, and quality of life in survivors of breast cancer: a randomized trial.

Purpose: Breast cancer treatments often lead to unfavourable changes in body composition, physical fitness, and quality of life (QoL). We compared the effects of resistance training (RT) and high-intensity interval training (HIIT) on these outcomes in survivors of breast cancer.

Methods: Twenty-eight survivors of breast cancer, post-treatment (Stage I-III), aged 55.5 ± 8.8 years and body mass index 27.9 ± 5 kg/m² were randomly allocated to a 12-week supervised RT (n = 14) or HIIT (n = 14) intervention, 3 days per week. Body composition (dual energy x-ray absorptiometry), upper and lower body muscle strength (1-repetition maximum), cardiorespiratory fitness (CRF) (Ekblom Bak Cycle Test), and QoL domains (EORTC QLQ-C30 and EORTC QLQ-BR45) were assessed at baseline and 12 weeks.

Results: There were no significant differences between groups at baseline. Exercise attendance ranged from 81 to 85%. Between groups, there were significant differences (p ≤ 0.001) after 12 weeks in chest press strength for RT (mean difference [MD] = 4.7 kg) and CRF for HIIT (MD = 1.9 ml/min/kg). Within groups, there were significant improvements (p < 0.05) for % lean mass and % fat mass in both RT and HIIT, as well as for upper and lower body muscle strength, CRF, and QoL domains. No major adverse events were noted.

Conclusion: Both exercise groups improved body composition, physical fitness, and QoL domains over 12 weeks of RT or HIIT, although mode-specific benefits were apparent with more substantial improvements in lean mass and muscle strength with RT and reductions in % fat mass and improved CRF with HIIT. Tailored exercise programs should address the specific health needs of each patient.