# A randomized trial on the feasibility of high-intensity interval training during chemotherapy in young breast cancer patients PMID: 41152283 Journal: Scientific reports Published: 2025-10-28 Authors: Górecki M, Kufel-Grabowska J, Dudek M, Litwiniuk M, Nowak A, Bartczak-Rutkowska A, Straburzyńska-Migaj E, Doś J, Marszałek A, Nowaczyk P, Lembryk M, Piotrowski I, Suchorska W, Lesiak M, Marszałek S ## Question Can HIIT be successfully implemented during chemotherapy in young breast cancer patients, and what are its exploratory effects on body composition and handgrip strength? ## Summary This randomized open-label trial tested whether supervised HIIT could be delivered during neoadjuvant chemotherapy in young women with breast cancer. Forty women aged 18-40 were randomized to supervised HIIT plus chemotherapy or chemotherapy plus physical-activity guidance. HIIT was performed twice weekly for 6 months in small supervised groups, progressed from 75% HRmax to 80%-90% HRmax, and used multiple cardio stations. Feasibility was high among the HIIT group: retention was 94.74%, the 18 retained participants attended all training sessions, and no training-related adverse events were observed. Exploratory outcomes showed preservation of affected-side handgrip strength versus decline in controls, while between-group body-composition differences were not significant. ## Population - Young women aged 18-40 with breast cancer undergoing neoadjuvant chemotherapy. - Sample size: 40 - Age: Control mean 34.9 years; HIIT mean 34.4 years. - Sex: Women only. - Fitness level: ECOG 0-1 and relatively good physical health; capable of high-intensity exercise. - Health status: Breast cancer treated with neoadjuvant chemotherapy; LVEF greater than 50% and adequate lab values required. ## Methodology - Open-label, parallel, randomized quantitative superiority trial. - Approximately 6 months during neoadjuvant chemotherapy. - Greater Poland Cancer Centre, Poznan, Poland; supervised group training in hospital physiotherapy context. - Randomized and controlled study design. ## Protocol - Supervised HIIT during chemotherapy. - Modality: Circuit cardio machines: treadmill, elliptical bike, cycle ergometer, rowing machine, endurance stepper. - Work intervals: 1:15 at up to 75% HRmax in month 1; 1:30, 1:45, then 2:00 at 80%-90% HRmax over months 2-6. - Recovery: 4 minutes active walking between sets. - Sets or repetitions: 4 sets in month 1; 5 sets in months 2-6. - Intensity: 75% HRmax progressing to 80%-90% HRmax; HRmax calculated as 220 minus age. - Session duration: Approximately 40 minutes including warm-up and stretching/relaxation. - Frequency: Twice weekly supervised, plus one instructed 45-minute individual aerobic session weekly. - Program length: 6 months. - Progression: Two mesocycles with increasing intensity and interval duration: month 1 skill/safety at 75% HRmax, months 2-6 at 80%-90% HRmax with longer work intervals. - WHO physical activity guidance control. - Modality: Unsupervised aerobic physical activity guidance during chemotherapy. - Intensity: 150-300 min/week moderate-intensity aerobic activity or 75-150 min/week vigorous aerobic activity. - Frequency: Throughout chemotherapy. - Program length: 6 months. ## Outcomes ### HIIT retention Status: improved 18 of 19 HIIT participants completed the intervention, exceeding the prespecified 80% retention threshold. Retention 94.74%, 95% CI 99.07%-75.36%. ### HIIT adherence Status: improved All 18 retained HIIT participants attended all training sessions, exceeding the prespecified 70% adherence threshold. Adherence 100%, 95% CI 100%-82.41%. ### Training-related adverse events Status: no clear change No adverse events related to physical training were observed in the HIIT group. ### Body composition Status: mixed HIIT participants had within-group increases in weight and muscle mass and a BMI decrease, but adjusted between-group body-composition outcomes were not significantly different. HIIT within-group weight p=0.0271, muscle mass p=0.0041, BMI p=0.0232; between-group ANCOVA p=0.375 for weight, p=0.509 for BMI, p=0.058 for muscle mass, p=0.811 for fat mass. ### Affected-side handgrip strength Status: improved Control affected-side handgrip declined after chemotherapy while HIIT affected-side handgrip was preserved, yielding a significant adjusted between-group difference. Control 28.9 to 27.9 kg, p=0.0109; HIIT 32.1 to 32.1 kg, p=0.9333; between-group difference 1.2 kg, 95% CI 0.2-2.2, ANCOVA p=0.025. ### Unaffected-side handgrip strength Status: no clear change No significant between-group difference was found for unaffected-side handgrip in the primary analysis. Between-group difference 0.4 kg, 95% CI -0.4 to 1.3, ANCOVA p=0.312. ## Practical Insights - In selected young chemotherapy patients, supervised HIIT can achieve high retention and attendance when sessions are flexible and professionally monitored. - A progressive first-month skill/safety phase before harder intervals is a useful clinical programming pattern. - For consumer translation, this evidence should be used for clinical-context education rather than direct workout prescription. ## Limitations - Intensity adherence was not verified throughout every session or work bout. - Control group had higher weekly steps than HIIT group. - Control group may have undertaken additional unsupervised activity. - Participants were young, women only, ECOG 0-1, and relatively fit. - Specialized supervised clinical setting limits generalizability. - Physical activity monitor has accuracy limitations. ## Safety And Adherence - No physical-training-related adverse events were observed in the HIIT group. - Safety monitoring included heart-rate chest strap and symptom checks for nausea, dizziness, persisting muscle pain, and joint pain. - One HIIT participant missed post-intervention assessment due to ongoing infection, not reported as training-related. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/41152283/) (pubmed) - [DOI](https://doi.org/10.1038/s41598-025-18377-0) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12569209/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.