The effect of glucose ingestion on endurance upper-body exercise and performance

The physiological responses to glucose supplementation during arm crank exercise were investigated. Ten subjects of mean age 28 ± 8 years; stature 180.8 ± 6.5 cm; mass 82.7 ± 11.5 kg, VO₂peak 3.10 ± 0.501 × min^-1 were tested on two occasions separated by a week. A 7.6% glucose drink or placebo was administered in a blind crossover design 20 min prior to exercise. Subject's arm cranked for 60 min at an exercise intensity of 65% VO₂peak followed by a 20 min performance test. Rate of ventilation, oxygen uptake, RER, heart rate and blood lactate demonstrated similar responses between trials throughout the course of the hour. The blood glucose concentrations at rest were similar between trials increasing after glucose ingestion to show a significant difference (p < 0.05) to the placebo trial at the onset of exercise, then returning to resting values after 20 min. The 20 min performance tests revealed that after glucose ingestion athletes achieved a greater mean distance of 12.55 ± 1.29 km than in the placebo trial of 11.50 ± 1.68 km (p<0.05). In conclusion, the results showed that after one-hour of arm crank exercise, performance over a further twenty minutes was improved when glucose was ingested twenty minutes prior to exercise.