Fluid Ingestion During Distance Running

Abstract

Four highly trained marathon runners were studied 10 determine the influence of fluid loss and replacement on selected physiological variables. Each runner performed three two-hour treadmill runs at about 70% of his aerobic capacity 10 assess the value of drinking a glucose-electrolyte (GE) solution or water ingestion (WI) during exhaustive work. When fluids were ingested during the treadmill runs, a leveling of rectal temperature was observed after about 45 minutes of exercise. Glucose-electrolyte feedings maintained the serum electrolytes near the pre-exercise level, elevated the blood glucose, and maintained carbohydrate metabolism during the final 60 minutes of running. Measurements of the gastric residue after exercise showed no significant difference between the GE and WI volumes. The rate of gastric emptying, fluid loss, and international rules reduce the effectiveness of drinking fluids during marathon competition.