TY - JOUR

T1 - Effect of carbohydrate supplementation on plasma glutamine during prolonged exercise and recovery

AU - Van Hall, Gerrit

AU - Saris, W H

AU - Wagenmakers, A J

N1 - Keywords: Adult; Alanine; Amino Acids; Amino Acids, Branched-Chain; Ammonia; Analysis of Variance; Bicycling; Blood Glucose; Dietary Carbohydrates; Dietary Supplements; Exercise Test; Exercise Tolerance; Glucose; Glutamine; Glycogen; Humans; Lactates; Male; Muscle, Skeletal; Physical Exertion; Rest; Time Factors; Water

PY - 1998

Y1 - 1998

N2 - Muscle glycogen and glucose have been suggested to be carbon-chain precursors for glutamine synthesis in skeletal muscle. Therefore, the aim of the present study is to investigate whether carbohydrate supplementation affects plasma glutamine and other amino acids during exercise and 7 h of recovery. Eight well-trained subjects cycled at an alternating workload of 50 and 80% Wmax until exhaustion (59 to 140 min). During the exercise bout the subjects received either water (control) or a carbohydrate (CHO) drink (83 g CHO x l(-1), 2 ml x kg(-1) per kg body weight every 15 min). Plasma glutamine concentration appeared not to be affected by exercise, as a significant increase was only observed at some points in time during the control test. During recovery, however, plasma glutamine concentration decreased from 682+/-24 and 685+/-19 micromol x l(-1) at exhaustion to 552+/-19 and 534+/-12 micromol x l(-1) after 2 h of recovery for the control and CHO test, respectively. Plasma glutamine concentration returned to pre-exercise values after 7 h of recovery. Alanine concentration increased during exercise in both tests. During the recovery period the concentration of alanine (48%), and total amino acids (23%) decreased below the pre-exercise level. The plasma alanine and the total amino acid concentration was still suppressed after 7 h of recovery. In conclusion, carbohydrate supplementation had neither an effect during exercise nor during recovery on the concentration of plasma glutamine or other amino acids. Exercise, however, causes a substantial decrease in the plasma amino acid concentration during recovery.

AB - Muscle glycogen and glucose have been suggested to be carbon-chain precursors for glutamine synthesis in skeletal muscle. Therefore, the aim of the present study is to investigate whether carbohydrate supplementation affects plasma glutamine and other amino acids during exercise and 7 h of recovery. Eight well-trained subjects cycled at an alternating workload of 50 and 80% Wmax until exhaustion (59 to 140 min). During the exercise bout the subjects received either water (control) or a carbohydrate (CHO) drink (83 g CHO x l(-1), 2 ml x kg(-1) per kg body weight every 15 min). Plasma glutamine concentration appeared not to be affected by exercise, as a significant increase was only observed at some points in time during the control test. During recovery, however, plasma glutamine concentration decreased from 682+/-24 and 685+/-19 micromol x l(-1) at exhaustion to 552+/-19 and 534+/-12 micromol x l(-1) after 2 h of recovery for the control and CHO test, respectively. Plasma glutamine concentration returned to pre-exercise values after 7 h of recovery. Alanine concentration increased during exercise in both tests. During the recovery period the concentration of alanine (48%), and total amino acids (23%) decreased below the pre-exercise level. The plasma alanine and the total amino acid concentration was still suppressed after 7 h of recovery. In conclusion, carbohydrate supplementation had neither an effect during exercise nor during recovery on the concentration of plasma glutamine or other amino acids. Exercise, however, causes a substantial decrease in the plasma amino acid concentration during recovery.

M3 - Journal article

C2 - 9562214

VL - 19

SP - 82

EP - 86

JO - International Journal of Sports Medicine

JF - International Journal of Sports Medicine

SN - 0172-4622

IS - 2

ER -