Abstract
BACKGROUND: Muscle wasting in chronic heart failure (CHF) is a result of increased catabolism induced by proinflammatory cytokines like tumor necrosis factor [alpha] (TNF-[alpha]) and interleukin 6 (IL-6), and decreased anabolism due to alterations in the insulin-like growth factor 1 (IGF-1)/growth hormone (GH) axis. The goal of this study was to analyze the effects of 3 different training modalities (endurance training, strength training, and combined strength and endurance training [CT]) on circulating cytokines, IGF-1, and GH levels.
METHODS: Patients with CHF (N = 45), NYHA class II-III, left ventricular ejection fraction < 35%, were randomly assigned to 1 of 3 training modalities. They trained for 40 sessions, 3 times weekly. Fifteen CHF patients served as a control group. Blood samples were collected at baseline and 48 hours after the last training session.
RESULTS: There was a significant decrease in circulating IL-6 with all 3 training modalities. Tumor necrosis factor [alpha] levels decreased in the training groups and reached statistical significance for the CT group. No change was observed in the control group. There was no difference between the 4 groups. When comparing all trained patients with the control group, the decrease in IL-6 was significant. Concerning IGF-1 and GH, there was no change with training and no change in the control group.
CONCLUSION: Exercise training has no effects on circulating IGF-1 and GH. The decreases in cytokines are evident only when all trained patients are compared with the control group, independently of the modality of training intervention.