Effects of Concurrent Training on Resting and Progressive Exercise Metabolism in Breast Cancer Survivors with Metabolic Syndrome Risk Factors

Background/Objectives: Cancer pathophysiology involves metabolic disturbances, and exercise improves muscle metabolism, but little is known about the effect of concurrent high-intensity interval plus resistance training (CTHIIT+RT) on the resting and exercise metabolism of breast cancer survivors with risk factors related to metabolic syndrome (MetS). The purpose of this study was to determine the effects of 8 weeks of CTHIIT+RT on the fat and carbohydrate (CHO) metabolism during rest and progressive exercise post-exercise intervention in breast cancer survivors with histories of high- and low-volume chemotherapy. Methods: An experimental study was conducted in which (n = 21) women breast cancer survivors (age: 58.7 ± 8.7 years) were divided by history of high- (HVchemo, ≥8 to 16 sessions, n = 10) or low-volume (LVchemo, ≤7 chemo sessions, n = 11) chemotherapy. The fat (RFATox) and CHO oxidation during 10 min of resting was measured (i.e., including the area under curve [AUC] points within this time), as well as the fat (ExFATox) and CHO (ExCHOox) oxidation during progressive exercise, before and after 8 weeks of CTHIIT+RT by indirect calorimetry. Additionally, risk factors related to MetS were described from pre- to post-intervention. Results: At rest, the HVchemo group showed significant increases in the AUC of RFATox (∆ + 23.7, p < 0.0001), similar to the LVchemo group (∆ + 14.0, p < 0.0001). The HVchemo group showed significant increases in the AUC of RCHOox (∆ + 109.7, p < 0.0001), similar to the LVchemo group (∆ + 107.5, p < 0.0001). During progressive exercise, the ExFATox was increased in the HVchemo group (∆ + 0.12 g/min, p = 0.006), similar to the ExCHOox (∆ + 0.52 g/min, p = 0.013) of this group. The proportion of subjects categorized with MetS were significantly reduced in blood pressure, Glu and triglyceride components. Conclusions: Eight weeks of CTHIIT+RT may promote favorable metabolic and cardiometabolic adaptations in breast cancer survivors regardless of the chemotherapy exposure volume. However, these findings should be interpreted cautiously due to the small sample size and lack of a true non-exercise control group.