Objective: Exercise training is recently considered as a trend in adjuvant therapies for cancer patients, but its mechanisms need to be scrutinized further. This study is aimed to test the hypothesis that the patients who perform the high-intensity interval exercise training (HIIT) during hormone therapy would show improvements in low-grade inflammation and HSP70 compared to the controls receiving standard care.
Methods: Fifty two non-metastatic and hormone-responsive breast cancer patients were randomly assigned to high-intensity interval exercise (HIIT) (n = 26) and usual care (n = 26) groups. The HIIT groups participated in a high-intensity interval training protocol on a treadmill 3 days/week for 12 weeks. The training intensity was determined according to the predicted maximal heart rate. Demographic characteristics and medical history were collected via an interviewer-administered questionnaire at the baseline visit. Body fat was estimated based on skinfold thickness measured with calipers on the participant's nonsurgery side at the triceps, suprailiac crest. [Formula: see text] was estimated by 1-Mile Rockport Walk Test. Blood samples were collected 48 h before starting the exercise protocol and 48 h after the last exercise session. TNF-α, IL-6, IL-1β, IL-10, and HSP70 levels in serum were measured using the enzyme-linked immunosorbent assay (ELISA) method according to the manufacture's instruction. Supernatant cytokine concentrations were determined by ELISA for IL-4 and IFN-γ. The data were analyzed by ANCOVA test that the pretest values were considered as covariate at P ≤ 0.05.
Results: HIIT improved [Formula: see text] in the HIIT group compared to the usual care group (P = 0.002). The serum levels of TNF-α (P = 0.001), IL-6 (P = 0.007), and IL-10 (P = 0.001) were lower in the HIIT group. The level of IL-4 (P = 0.050) in the stimulated peripheral blood mononuclear cells significantly increased in the HIIT group compared to the usual care group. Furthermore, the serum level of the HSP70 was significantly higher in the HIIT group in comparison to the usual care group (P = 0.050). The TNF-α/IL-10 (P = 0.050) and IL-6/IL-10 (P = 0.042) ratios were lower in the HIIT group.
Conclusion: The results of this study indicated that HIIT has positive impacts on the cardiorespiratory fitness and inflammatory cytokines in the breast cancer patients undergoing hormone therapy.
Keywords: Breast cancer; Cytokine; HIIT; HSP70; IFN-γ; IL-4.