Effect of pre-exercise carbohydrate ingestion on plasma cytokine, stress hormone, and neutrophil degranulation responses to continuous, high-intensity exercise

• Published in: International journal of sport nutrition and exercise metabolism 2003-12, Vol.13 (4), p.436-453
• Main Authors: Lancaster, Graeme I, Jentjens, Roy L P G, Moseley, Luke, Jeukendrup, Asker E, Gleeson, Michael
• Format: Article
• Language: English
• Subjects: Adult; Bicycling - physiology; Blood Glucose - analysis; Cell Degranulation - immunology; Dietary Carbohydrates - blood; Dietary Carbohydrates - immunology; Dietary Carbohydrates - pharmacokinetics; Dose-Response Relationship, Drug; Exercise Test; Humans; Hydrocortisone - blood; Insulin - blood; Interleukin-6 - blood; Interleukin-6 - immunology; Lactic Acid - blood; Leukocyte Count; Lipopolysaccharides - pharmacology; Male; Neutrophils - immunology; Neutrophils - physiology; Pancreatic Elastase - blood
• ISSN: 1526-484X; 1543-2742
• DOI: 10.1123/ijsnem.13.4.436

The purpose of the present study was to examine the effect of pre-exercise carbohydrate (CHO) ingestion on circulating leukocyte numbers, plasma interleukin (IL)-6, plasma cortisol, and lipopolysaccharide (LPS)-stimulated neutrophil degranulation responses in moderately trained male cyclists who completed approximately 1-h of high-intensity cycling. The influence of the timing of pre-exercise CHO ingestion was investigated in 8 subjects who consumed 75 g CHO as a glucose solution at either 15 (-15 trial), or 75 (-75 trial) min before the onset of exercise. The influence of the amount of pre-exercise CHO ingestion was investigated in a further 10 subjects who consumed either 25 g or 200 g CHO as a glucose solution or a placebo 45 min before the onset of exercise. At the onset of exercise in the timing experiment, the plasma glucose concentration was significantly (p < .05) lower on the -75 trial compared with pre-drink values, and the plasma cortisol concentration and neutrophil to lymphocyte (N/L) ratio were significantly (p < .05) elevated in the post-exercise period. In the -15 trial, plasma glucose level was well maintained, and the plasma cortisol concentration and N/L ratio were not significantly elevated above resting levels. However, LPS-stimulated neutrophil degranulation was similar in the -15 and -75 trials. The amount of CHO ingested had no effect on the magnitude of the rise in the N/L ratio compared with placebo when consumed 45 min pre-exercise. Finally, although an exercise-induced increase in the plasma IL-6 concentration was observed, this effect was independent of pre-exercise CHO ingestion.