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No effect of nutritional adenosine receptor antagonists on exercise performance in the heat.
Am J Physiol Regul Integr Comp Physiol. 2009 Feb; 296(2):R394-401.AJ

Abstract

Nutritional adenosine receptor antagonists can enhance endurance exercise performance in temperate environments, but their efficacy during heat stress is not well understood. This double-blinded, placebo-controlled study compared the effects of an acute dose of caffeine or quercetin on endurance exercise performance during compensable heat stress (40 degrees C, 20-30% rh). On each of three occasions, 10 healthy men each performed 30-min of cycle ergometry at 50% Vo2peak followed by a 15-min performance time trial after receiving either placebo (Group P), caffeine (Group C; 9 mg/kg), or quercetin (Group Q; 2,000 mg). Serial blood samples, physiological (heart rate, rectal, and mean skin body temperatures), perceptual (ratings of perceived exertion, pain, thermal comfort, motivation), and exercise performance measures (total work and pacing strategy) were made. Supplementation with caffeine and quercetin increased preexercise blood concentrations of caffeine (55.62 +/- 4.77 microM) and quercetin (4.76 +/- 2.56 microM) above their in vitro inhibition constants for adenosine receptors. No treatment effects were observed for any physiological or perceptual measures, with the exception of elevated rectal body temperatures (0.20-0.30 degrees C; P < 0.05) for Group C vs. Groups Q and P. Supplementation did not affect total work performed (Groups P: 153.5 +/- 28.3, C: 157.3 +/- 28.9, and Q: 151.1 +/- 31.6 kJ; P > 0.05) or the self-selected pacing strategy employed. These findings indicate that the nutritional adenosine receptor antagonists caffeine and quercetin do not enhance endurance exercise performance during compensable heat stress.

Authors+Show Affiliations

U.S. Army Research Institute of Environmental Medicine, Thermal and Mountain Medicine Division, Kansas St., Natick, MA 01760-5007, USA. samuel.n.cheuvront@us.army.milNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Randomized Controlled Trial
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

19020291

Citation

Cheuvront, Samuel N., et al. "No Effect of Nutritional Adenosine Receptor Antagonists On Exercise Performance in the Heat." American Journal of Physiology. Regulatory, Integrative and Comparative Physiology, vol. 296, no. 2, 2009, pp. R394-401.
Cheuvront SN, Ely BR, Kenefick RW, et al. No effect of nutritional adenosine receptor antagonists on exercise performance in the heat. Am J Physiol Regul Integr Comp Physiol. 2009;296(2):R394-401.
Cheuvront, S. N., Ely, B. R., Kenefick, R. W., Michniak-Kohn, B. B., Rood, J. C., & Sawka, M. N. (2009). No effect of nutritional adenosine receptor antagonists on exercise performance in the heat. American Journal of Physiology. Regulatory, Integrative and Comparative Physiology, 296(2), R394-401. https://doi.org/10.1152/ajpregu.90812.2008
Cheuvront SN, et al. No Effect of Nutritional Adenosine Receptor Antagonists On Exercise Performance in the Heat. Am J Physiol Regul Integr Comp Physiol. 2009;296(2):R394-401. PubMed PMID: 19020291.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - No effect of nutritional adenosine receptor antagonists on exercise performance in the heat. AU - Cheuvront,Samuel N, AU - Ely,Brett R, AU - Kenefick,Robert W, AU - Michniak-Kohn,Bozena B, AU - Rood,Jennifer C, AU - Sawka,Michael N, Y1 - 2008/11/19/ PY - 2008/11/21/pubmed PY - 2009/3/13/medline PY - 2008/11/21/entrez SP - R394 EP - 401 JF - American journal of physiology. Regulatory, integrative and comparative physiology JO - Am. J. Physiol. Regul. Integr. Comp. Physiol. VL - 296 IS - 2 N2 - Nutritional adenosine receptor antagonists can enhance endurance exercise performance in temperate environments, but their efficacy during heat stress is not well understood. This double-blinded, placebo-controlled study compared the effects of an acute dose of caffeine or quercetin on endurance exercise performance during compensable heat stress (40 degrees C, 20-30% rh). On each of three occasions, 10 healthy men each performed 30-min of cycle ergometry at 50% Vo2peak followed by a 15-min performance time trial after receiving either placebo (Group P), caffeine (Group C; 9 mg/kg), or quercetin (Group Q; 2,000 mg). Serial blood samples, physiological (heart rate, rectal, and mean skin body temperatures), perceptual (ratings of perceived exertion, pain, thermal comfort, motivation), and exercise performance measures (total work and pacing strategy) were made. Supplementation with caffeine and quercetin increased preexercise blood concentrations of caffeine (55.62 +/- 4.77 microM) and quercetin (4.76 +/- 2.56 microM) above their in vitro inhibition constants for adenosine receptors. No treatment effects were observed for any physiological or perceptual measures, with the exception of elevated rectal body temperatures (0.20-0.30 degrees C; P < 0.05) for Group C vs. Groups Q and P. Supplementation did not affect total work performed (Groups P: 153.5 +/- 28.3, C: 157.3 +/- 28.9, and Q: 151.1 +/- 31.6 kJ; P > 0.05) or the self-selected pacing strategy employed. These findings indicate that the nutritional adenosine receptor antagonists caffeine and quercetin do not enhance endurance exercise performance during compensable heat stress. SN - 0363-6119 UR - https://www.unboundmedicine.com/medline/citation/19020291/No_effect_of_nutritional_adenosine_receptor_antagonists_on_exercise_performance_in_the_heat_ L2 - http://www.physiology.org/doi/full/10.1152/ajpregu.90812.2008?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -