Long-term high-intensity aerobic interval training in stage II – III breast cancer patients receiving neoadjuvant chemotherapy 

Abstract Background. Although higher-intensity aerobic interval training (HIIT) is recognized as a modality to attenuate breast cancer (BC) treatment-induced decline in cardiorespiratory endurance and mitigate side effects, it is still really offered as an addition to treatment. Thus, this study investigated the 6-month effects and feasibility of HIIT for BC patients undergoing neoadjuvant chemotherapy (NACT). Methods. Thirty-five women (mean age 47 ± 8 years) diagnosed with stage II-III BC before initial treatment were randomized to either the training group (TG) or non–exercise control group (CG). TG was instructed to perform 4x4 min intervals remotely at an intensity of 85-95% of peak heart rate, 2-3 times a week for 6 months. Treadmill VO2peak and functional performance were assessed before and after the exercise period. Results. After the intervention, TG maintained VO2peak (P=0.94) but decreased in the CG by (13% ± 7%; P<0.001.), a significant difference between the groups with a large effect was absorbed post-intervention (P=0.005). Significant increases were observed (5% ± 4%; P=0.043) in the time to exhaustion for TG while it reduced in CG (9% ± 6%; P=0.003), a significant difference was apparent between the groups post-intervention (P<0.038). Moreover, the TG increased distance in a 6-min walking test (6MWT) by (7% ± 6%; P=0.006), times in a 30-s chair stand test by (19% ± 10%; P=0.003), and 5x sit-to-stand test by (20% ± 14%; P<0.001). Conversely, no changes were observed in the CG in these variables. Significant changes were present between the groups post-intervention 6MWT (P<0.001), 30 – s char stand test (P=0.05), and 5x sit-to-stand test (P=0.015). Conclusion. 6 months of HIIT during NACT is feasible, safe, manageable, and effectively improves cardiorespiratory endurance and functional performance. These results advocate that HIIT should be considered in BC treatment.