PHYSILOGICAL RESPONSES TO RESISTANCE EXERCISE IN MEN WITH AND WITHOUT LEFT VENTRICULAR HYPERTROPHY

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The purpose of the present study was to determine the physiological response of resistance exercise on hormonal and insulin-like growth factors (IGF-I, freeIGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) concentrations in men with and without a diagnosis of left ventricular hypertrophy. M-mode and two-dimensional Doppler-echocardiography were performed in 18 resistance trained men and a control group of 10 healthy untrained subjects. Both groups were subjected to isometric, eccentric and concentric resistance exercise. Venous blood samples were drawn before and immediately after the test and during a 1-hour recovery for determination of hormonal and somatomedin concentrations. Eccentric muscle contraction resulted in a significant increase of serum IGF-I concentration (p<0.05) in subjects diagnosed to have left ventricular hypertrophy (LVH) when compared to those with normal upper limit of left ventricular wall thickness (LVN) and control group (CG), (p<0.01). Our results seem to have demonstrated that concentric and eccentric muscle actions stimulate circulating IGF-I increase. Increased serum IGF-I concentration might be responsible for physiological heart hypertrophy seen in trained subjects predominantly engaged in eccentric resistance exercise.