Acute Hormonal Responses To Restriction Of Leg Muscle Blood Flow During Walking

Abstract

Low-intensity resistance exercise (20% of one-repetition maximal) combined with restriction of muscle blood flow (namely KAATSU) increases plasma growth hormone (GH) concentration. In general, walking slowly has no effect on acute GH response. PURPOSE To examine the acute responses of serum GH, free testosterone, and cortisol to slow walking combined with KAATSU. METHODS 11 male college students performed walking (50 m/min for five 2 min bouts; 1 min rest between bouts) with and without KAATSU (the proximal end of their thigh compressed at 130% of resting systolic blood pressure throughout the walking session) on separate days. Venous blood samples were obtained prior to the start of exercise (Pre), and immediately (IP), 15- (15P) and 60-min (60P) after exercise. RESULTS Serum GH concentration was elevated (P<0.01) from Pre [1.72 (0.83) ng/ml] to IP [12.4 (3.2) ng/ml] and 15P [13.1 (2.4) ng/ml] in the walking with KAATSU. Free testosterone was also elevated (P<0.05) from Pre [12.7 (1.2) pg/ml] to IP [16.0 (1.3) pg/ml] in the walking with KAATSU. Neither GH [Pre, 1.67 (0.97) ng/ml; IP, 1.39 (0.91), 15P, 1.26 (0.92)] nor free testosterone [Pre, 14.3 (1.3) pg/ml; IP, 14.1 (1.2)] increased during the walking without KAATSU. Cortisol concentration showed a gradual decrease (P<0.05) during the experiments in both walking with and without KAATSU. CONCLUSIONS The results of the present investigation with young male students indicated that slow walking with KAATSU caused greater responses in serum GH and free testosterone compared to normal slow walking.