Immunoendocrine response to cycling following ingestion of caffeine and carbohydrate.
OBJECTIVE
This study investigated the effect of caffeine consumed with and without carbohydrate (CHO) on immunoendocrine responses after exercise.


METHODS
On four occasions, 12 recreational male cyclists cycled for 2 h at 65% V O2max. Sixty minutes before exercise, participants ingested 6 mg.kg(-1) body mass of caffeine (CAF) or placebo (PLA), then during exercise they consumed a 6% CHO or placebo (PLA) drink, providing CAF/CHO, PLA/CHO, CAF/PLA, and PLA/PLA conditions.


RESULTS
f-MLP-stimulated neutrophil oxidative burst responses were significantly higher after exercise on CAF/CHO and PLA/CHO (both P<0.05) than PLA/PLA when expressed as a percentage of baseline value. The response on CAF/PLA tended to be higher than PLA/PLA at this point (P=0.056). No significant differences between CAF/CHO, PLA/CHO, and CAF/PLA were observed after exercise; however, only PLA/CHO showed no significant postexercise decline. Coingestion of CAF/CHO significantly attenuated epinephrine (P<0.05) and IL-6 (P<0.05) responses that occurred after ingestion of CAF alone (CAF/PLA) and significantly attenuated the transient alterations in circulating leukocyte (P<0.05) and neutrophil (P<0.01) counts. Plasma cortisol concentration was significantly lower on PLA/CHO than CAF/PLA and PLA/PLA after exercise (P<0.05). Perceived exertion during exercise was significantly lower on CAF/CHO than the other three trials (P<0.05).


CONCLUSIONS
Taken together, this suggests that coingestion of caffeine and CHO has greater influence on immunoendocrine responses than neutrophil functional responses to prolonged exercise.
Walker
Gary J
GJ
School of Sport and Exercise Sciences, Loughborough University, Leicestershire, UK. G.J.Walker2@lboro.ac.uk
Finlay
Oliver
O
Griffiths
Hannah
H
Sylvester
James
J
Williams
Mark
M
Bishop
Nicolette C
NC
D000328:Adult; D001642:Bicycling / Q000502:physiology*; D002110:Caffeine / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D002241:Carbohydrates / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D004703:Endocrine System / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007107:Immune System / Q000187:drug effects* / Q000502:physiology; D007958:Leukocyte Count; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects; D016897:Respiratory Burst / Q000187:drug effects* / Q000502:physiology