X-Message-Number: 14418 Date: Tue, 5 Sep 2000 20:35:26 -0700 (PDT) From: Doug Skrecky <> Subject: exercise with mild vascular occlusion stimulates growth hormone Citation 1 of 2: Effects of Resistance Exercise Combined With Moderate Vascular Occlusion on Muscular Function in Humans Journal of Applied Physiology 88(6): 2097-106 June 2000 Abstract: Acute and long-term effects of resistance exercise combined with vascular occlusion on muscular function were investigated. Changes in integrated electromyogram with respect to time (iEMG), vascular resistive index, and plasma lactate concentration were measured in five men either during or after elbow flexion exercises with the proximal end of the arm occluded at 0-100 mmHg. The mean iEMG, postexercise hyperemia, and plasma lactate concentration were all elevated with the increase in occlusion pressure at a low-intensity exercise, whereas they were unchanged with the increase in occlusion pressure at high-intensity exercise. To investigate the long-term effects of low-intensity exercise with occlusion, older women (n = 24) were subjected to a 16-wk exercise training for elbow flexor muscles, in which low-intensity [approximately 50-30% one repetition maximum (1 RM) exercise with occlusion at approximately 110 mmHg (LIO), low-intensity exercise without occlusion (LI), and high- to medium-intensity (approximately 80-50% 1 RM) exercise without occlusion (HI) were performed. Percent increases in both cross-sectional area and isokinetic strength of elbow flexor muscles after LIO were larger than those after LI (P<0.05) and similar to those after HI. The results suggest that resistance exercise at an intensity even lower than 50% 1 RM is effective in inducing muscular hypertropy and concomitant increase in strength when combined with vascular occlusion. Citation 2 of 2: Rapid Increase in Plasma Growth Hormone After Low-Intensity Resistance Exercise With Vascular Occlusion. Journal of Applied Physiology 88(1): 61-5 January 2000 Abstract: Hormonal and inflammatory responses to low-intensity resistance exercise with vascular occlusion were studied. Subjects (n=6) performed bilateral leg extension exercise in the seated position, with the proximal end of their thigh compressed at 214 +/- 7.7 (SE) mmHg throughout the session of exercise by means of a pressure tourniquet. Mean intensity and quantity of the exercise were 20% of 1 repetition maximum and 14 repetitions x 5 sets, respectively. In each set, the subjects repeated the movement until exhaustion. Plasma concentrations of growth hormone (GH), norepinephrine (NE), lactate (La), lipid peroxide (LP), interleukin-6 (IL-6), and activity of creatine phosphokinase (CPK) were measured before and after the exercise was finished and the tourniquet was released. Concentrations of GH, NE, and La consistently showed marked, transient increases after the exercise with occlusion, whereas they did not change a great deal after the exercise without occlusion (control) done at the same intensity and quantity. Notably, concentration of GH reached a level approximately 290 times as high as that of the resting level 15 min after the exercise. IL-6 concentration showed a much more gradual increase and was maintained at a slightly higher level than in the control even 24 h after exercise. Concentrations of LP and CPK showed no significant change. The results suggest that extremely light resistance exercise combined with occlusion greatly stimulates the secretion of GH though regional acculation of metabolites without considerable tissue damage. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=14418