Document Detail


Caffeine stimulates ventilation in athletes with exercise-induced hypoxemia.
MedLine Citation:
PMID:  18460998     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
INTRODUCTION/PURPOSE: Many athletes with exercise-induced hypoxemia (EIH) show an insufficient ventilatory response to exercise and low resting ventilatory responsiveness. The purpose of this project was to determine whether a moderate dosage of caffeine, a common ventilatory stimulant, could augment resting ventilatory responsiveness, exercise ventilation (V E), end-tidal O2 partial pressure (PetO2), and arterial oxyhemoglobin saturation (HbSaO2) in athletes with EIH. METHODS: Eight highly trained males (V[spacing dot above]O2max, 69.2 +/- 4.0 mL.[kg.min]) who demonstrated EIH at V[spacing dot above]O2max (HbSaO2, 88.0 +/- 1.7%), ingested in a randomized design a placebo or caffeine (CAF, 8 mg.kg body wt) 1 h before testing. Ventilatory responsiveness at rest was assessed via the isocapnic hypoxic and hyperoxic hypercapnic ventilatory responses (HVR and HCVR, respectively). Dependent measures of metabolic variables, ventilation, and saturation were determined during progressive treadmill exercise to exhaustion. RESULTS: V E was higher at 75%, 80%, and 100% of V[spacing dot above]O2max with CAF (P < 0.05). V E/V O2, PetO2, and HbSaO2 were increased at 75%, 80%, and 90% of [formula: see text] with CAF but were not different at V[spacing dot above]O2max despite an increase in V e. No change in V[spacing dot above]O2max was observed between treatments. HVR and HCVR were not different between the two conditions, indicating that the increased V E likely came from central stimulation or secondary effects of CAF. CONCLUSION: The failure of HbSaO2 to increase at [formula: see text] despite an increase in V E suggests that mechanisms influencing HbSaO2 other than an inadequate hyperventilatory response may operate to different degrees across individuals as V[spacing dot above]O2max is approached.
Authors:
Robert F Chapman; Joel M Stager
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Publication Detail:
Type:  Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  40     ISSN:  0195-9131     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  2008 Jun 
Date Detail:
Created Date:  2008-05-22     Completed Date:  2008-10-21     Revised Date:  2009-01-19    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1080-6     Citation Subset:  IM; S    
Affiliation:
Human Performance Laboratory, Department of Kinesiology, Indiana University, Bloomington, IN 47405, USA. rfchapma@indiana.edu
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MeSH Terms
Descriptor/Qualifier:
Adult
Anoxia / physiopathology*
Athletic Performance / physiology*
Caffeine / pharmacology*
Central Nervous System Stimulants / pharmacology*
Exercise Test
Humans
Male
Oxygen Consumption / drug effects
Oxyhemoglobins / drug effects
Pulmonary Ventilation / drug effects*
Chemical
Reg. No./Substance:
0/Central Nervous System Stimulants; 0/Oxyhemoglobins; 58-08-2/Caffeine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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