The influence of pre-exercise glucose ingestion on endurance running capacity.
Drinking a concentrated glucose solution less than 1 h before the start of prolonged submaximal exercise has been reported to reduce endurance capacity during cycling. The purpose of this study was to re-examine the influence of pre-exercise ingestion of a concentrated glucose solution on endurance running capacity. Nine recreational runners (five men and four women) ran to exhaustion on a level treadmill, at speeds equivalent to 70% VO2max, on two occasions separated by at least 1 week. The runners ingested either a solution containing 75 g of glucose in 300 ml of water (G trial), or 300 ml of sweetened water (P trial) 30 min before each trial. As a consequence, the blood glucose concentrations were 55% higher at the beginning of the G trial compared with those recorded for the P trial (G trial, mean(s.e.) blood glucose = 6.3(0.7) mmol l-1 versus P trial, mean(s.e.) blood glucose = 4.1(0.3) mmol l-1; P < 0.01). Nevertheless, there were no differences in the running times to exhaustion between the two trials (G trial, mean(s.e.) 133.79(11.0) min versus P trial, mean(s.e.) 121.16(8.1) min). The results of this study show that ingesting a 25% glucose solution 30 min before exercise does not reduce the endurance capacity of recreational runners when the exercise intensity is equivalent to 70% VO2max.
Chryssanthopoulos
C
C
Department of Physical Education, Sports Science and Recreation Management, Loughborough University, UK.
Hennessy
L C
LC
Williams
C
C
D000328:Adult; D004311:Double-Blind Method; D005260:Female; D005947:Glucose / Q000494:pharmacology*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007773:Lactates / Q000097:blood; D019344:Lactic Acid; D008297:Male; D010807:Physical Endurance / Q000187:drug effects* / Q000502:physiology*; D012119:Respiration / Q000187:drug effects; D012420:Running / Q000502:physiology*
D007773:Lactates; D019344:Lactic Acid; D005947:Glucose