Changes in Insulin Resistance in Trained Athletes Upon Cessation of Training

Abstract

<p> This study was designed to investigate possible changes in insulin sensitivity (IS) with cessation of training. Six endurance trained athletes were studied at 12, 60 h and 7 days following cessation of training. In-vivo IS was established by a glucose clamp technique (Greenfield et al. Diabetes 30, 1981) and expressed as the metabolic clearance rate of glucose (MCR) in ml. plasma cleared kg-1. min-1. At 12 h after the last training session the mean MCR was 15.6+1.8 compared with 7.8+1.2(p<0.01) in age and weight matched sedentary controls. The MCR decreased to 10.1+1.0 after 60 h and decreased significantly to 8.5+0.5(p<0.05) after 7 days of detraining. In-vitro IS was measured by determining the insulin binding of fractionated young erythrocytes by the method of Polychronakos et al. (Clin. Inves. Med.4,14B,1981). Insulin binding was 10.4+0.9% at 12 h and decreased significantly to 8.1+0.7%/4xl0^9 cells after 60 h of detraining (p<0.001). In conclusion: 1) detraining of endurance athletes resulted in a rapid decrease in IS. After 7 days, glucose MCR reached values indistinguishable from sedentary controls. 2) changes in IS observed may be partially mediated by alterations in insulin binding to receptors. 3) since the high IS observed with endurance athletes on the initial test disappeared shortly after cessation of training, it is probably an acute effect of the last exercise bout rather than a chronic effect of training.</p>