Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2009-1-27
pubmed:abstractText
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.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0363-6119
pubmed:author
pubmed:issnType
Print
pubmed:volume
296
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
R394-401
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed-meshheading:19020291-Adolescent, pubmed-meshheading:19020291-Adult, pubmed-meshheading:19020291-Body Temperature, pubmed-meshheading:19020291-Caffeine, pubmed-meshheading:19020291-Dietary Supplements, pubmed-meshheading:19020291-Double-Blind Method, pubmed-meshheading:19020291-Heart Rate, pubmed-meshheading:19020291-Heat Stress Disorders, pubmed-meshheading:19020291-Hot Temperature, pubmed-meshheading:19020291-Humans, pubmed-meshheading:19020291-Male, pubmed-meshheading:19020291-Muscle Fatigue, pubmed-meshheading:19020291-Oxygen Consumption, pubmed-meshheading:19020291-Perception, pubmed-meshheading:19020291-Physical Endurance, pubmed-meshheading:19020291-Purinergic P1 Receptor Antagonists, pubmed-meshheading:19020291-Quercetin, pubmed-meshheading:19020291-Time Factors, pubmed-meshheading:19020291-Water-Electrolyte Balance, pubmed-meshheading:19020291-Young Adult
pubmed:year
2009
pubmed:articleTitle
No effect of nutritional adenosine receptor antagonists on exercise performance in the heat.
pubmed:affiliation
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.mil
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, Non-P.H.S., Randomized Controlled Trial