High-Intensity Interval Training Is Feasible in Women at High Risk for Breast Cancer.

This trial aimed to demonstrate the feasibility of high-intensity interval training (HIIT) in postmenopausal, overweight/obese women at high risk of invasive breast cancer and to explore HIIT on changes in cardiorespiratory fitness (CRF), body weight, and body mass index (BMI) compared with moderate-intensity continuous training (MICT) and usual care (UC). Forty-four women were randomized to HIIT, MICT, or UC for a 12-wk, thrice weekly, supervised exercise intervention. HIIT included a 5-min warm-up at 50%-70% HRpeak, four cycles of 4 min at 90%-100% HRpeak, followed by 3 min at 50%-70% HRpeak. MICT consisted of 41 min at 60%-70% HRpeak. Feasibility was assessed by consent, adherence, compliance, and retention rates. CRF, body weight, and BMI were measured at baseline and end of study. Repeated-measures linear mixed models were used to assess within- and between-group differences. Average age was 63.9 ± 8.8 yr. BMI was 30.9 ± 5.7 kg·m. Participants completed 90% and 89% of HIIT and MICT workouts, respectively, with 100% compliance to the exercise prescriptions. No serious adverse events were reported. Compared with MICT and UC, HIIT exhibited improvements in change in treadmill time (101 s greater than MICT, and 125 s greater than UC, respectively, P < 0.001). Compared with UC, HIIT exhibited improvement in changes in absolute and relative V˙O2peak (a 0.15-L·min increase, P = 0.005, and a 2.3-mL·kg⋅min increase, P = 0.004). There were no significant differences between groups for body weight or BMI (P > 0.05). HIIT is feasible, safe, and seems to promote greater improvements in CRF compared with MICT and UC in women at high risk for breast cancer.