Interval versus continuous aerobic exercise training in breast cancer survivors--a pilot RCT

Abstract

Background: Exercise therapy is being explored in a variety of cancer populations to counteract treatment-related deconditioning. Higher intensity interval protocols are being prescribed to improve physical function and attenuate surrogates of comorbidity in non-cancer populations. The purpose of this study is to explore the safety of higher intensity exercise stimuli on cardiorespiratory fitness (VO2peak) in breast cancer survivors.

Methods: Postmenopausal breast cancer survivors were randomized into three groups: supervised aerobic interval training (AIT), supervised continuous moderate exercise training (CMT), and an unsupervised control group (CON). For 6 weeks, AIT exercised between 70 and 100% VO2peak, while CMT exercised between 60 and 70% VO2peak. Both groups followed a matched-work design.

Results: Thirty-three participants completed the study (age, 57.2 (9) years; weight, 67.6 (12) kg) with no adverse advents. Between-group baseline values were non-significant. VO2peak at baseline (25.3 (5.4) mL·kg(-1)·min(-1)) was below population norms. Compared to CON, cardiorespiratory fitness improved in AIT and CMT by 12% (P < 0.001) with no significant difference between exercise groups. AIT had a greater influence on lower extremity strength (P = 0.026) and body weight (P = 0.031).

Conclusion: This pilot study provides evidence that similar to CMT, AIT can safely increase VO2peak in a small group of breast cancer survivors. Further exploration of the benefits of implementing higher intensity training protocols is warranted.

Keywords: Aerobic capacity; Blood biomarkers; Exercise intensity; Neoplasm; Rehabilitation; Survivorship.