Effect of alcohol intake on muscle glycogen storage after prolonged exercise

1 Sports Science and Sports Medicine, Australian Institute of Sport, Belconnen, Australian Capital Territory 2616; 2 School of Health Sciences, Deakin University, Waurn Ponds, Victoria 3217; and 3 School of Health Sciences, Deakin University, Burwood, Victoria, 3125, Australia Submitted 3 February 2003 ; accepted in final form 16 April 2003 We studied the effects of alcohol intake on postexercise muscle glycogen restoration with samples from vastus lateralis being collected immediately after glycogen-depleting cycling and after a set recovery period. Six well-trained cyclists undertook a study of 8-h recovery (2 meals), and another nine cyclists undertook a separate 24-h protocol (4 meals). In each study, subjects completed three trials in crossover order: control (C) diet [meals providing carbohydrate (CHO) of 1.75 g/kg]; alcohol-displacement (A) diet (1.5 g/kg alcohol displacing CHO energy from C) and alcohol + CHO (AC) diet (C + 1.5 g/kg alcohol). Alcohol intake reduced postmeal glycemia especially in A trial and 24-h study, although insulin responses were maintained. Alcohol intake increased serum triglycerides, particularly in the 24-h study and AC trial. Glycogen storage was decreased in A diets compared with C at 8 h (24.4 ± 7 vs. 44.6 ± 6 mmol/kg wet wt, means ± SE, P < 0.05) and 24 h (68 ± 5 vs. 82 ± 5 mmol/kg wet wt, P < 0.05). There was a trend to reduced glycogen storage with AC in 8 h (36.2 ± 8 mmol/kg wet wt, P = 0.1) but no difference in 24 h (85 ± 9 mmol/kg wet wt). We conclude that 1 ) the direct effect of alcohol on postexercise glycogen synthesis is unclear, and 2 ) the main effect of alcohol intake is indirect, by displacing CHO intake from optimal recovery nutrition practices. ethanol; glycogen resynthesis Address for reprint requests and other correspondence: L. M. Burke, Dept. of Sports Nutrition, Australian Institute of Sport, P.O. Box 176, Belconnen, ACT, Australia 2616 (E-mail: louise.burke{at}ausport.gov.au ).