Additional cardiovascular fitness when progressing from moderate- to high-intensity exercise training in previously...

Cardiovascular disease, often secondary to chemotherapy, is the leading cause of death in BC survivors. Increased aerobic capacity improves post-rehabilitation survival; however, many cancer rehabilitation programs are limited to lower intensity training. High-intensity interval training (HIIT) is associated with the largest improvements in aerobic capacity; therefore, this study aimed to determine whether HIIT would cause a greater increase in VO₂peak than continuous moderate-intensity (MICT) exercise in previously trained BC survivors.

Twenty BC survivors who had completed a low/moderate-intensity exercise rehabilitation program performed a VO₂peak test and received a dual-energy X-ray absorptiometry (DXA) scan at baseline and after randomization into a 12-week HIIT or MICT program. ANOVA with repeated measures determined the effects of the different training programs on aerobic capacity and body composition.

Both groups began the training program near or above age- and sex-matched VO₂peak norms. Pre- to post-intervention improvements in VO₂peak (P = 0.006) and waist circumference (P = 0.007) were found in both groups; however, there were no between-group differences. Minute ventilation and peak workload increased in the HIIT group (P < 0.05) but not the MICT group. Body composition was not different after either training program.

These data suggest that transitioning from low/moderate-intensity exercise to moderate/high-intensity exercise causes further clinically relevant increases in VO₂peak in previously trained BC survivors. HIIT did not cause a significantly greater improvement in VO₂peak than MICT; however, future studies with greater intensity and frequency of training are encouraged.