Document Detail

Effects of pre-exposure to hyperbaric hyperoxia on high-intensity exercise performance.
MedLine Citation:
PMID:  18296957     Owner:  NLM     Status:  MEDLINE    
This study comprised 2 main experiments: one was to determine the oxidative DNA damage under hyperbaric hyperoxia (HBO), and the other was to evaluate the effects of pre-exposure to HBO on high-intensity exercise performance. Healthy subjects (n = 8) inspired 100% O2 in an experimental chamber at a pressure of 1.3 atmospheres absolute (ATA) for 50 minutes once per week for 2 weeks. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) was measured as a marker of DNA oxidative damage on day 0 and on days 1, 3, and 5 after each HBO exposure. To investigate the effects of pre-exposure to HBO on high-intensity exercise performance, subjects (n = 6) performed maximal isometric knee extensor exercise (30 repetitions x 2 sets) with and without HBO pre-exposure (100% O2 at 1.3 ATA for 50 minutes). Urinary 8-OHdG did not show any significant change after HBO exposure. Isometric knee extensor torque was significantly lower during the first half of the first set of exercises after HBO pre-exposure compared with the normobaric normoxia (NBO) trial. The decreased torque was associated with the lower integrated electromyography with respect to time. Changes in the degree of ischemia-reperfusion in the vastus lateralis muscle during exercise were larger in the HBO pre-exposure trial than in the NBO trial. Muscle fatigue index, serum lactate concentration, heart rate, and systolic blood pressure showed no differences between the 2 trials. These results indicated that HBO exposure was harmless to DNA, and HBO pre-exposure did not enhance high-intensity exercise performance. As a practical application, athletes who require maximal muscle strength should not inspire high-concentration of O2 just before their competitions because it might, as the case may be, impair their performance.
Shigeo Kawada; Kohei Fukaya; Masaru Ohtani; Kando Kobayashi; Chiho Fukusaki
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of strength and conditioning research / National Strength & Conditioning Association     Volume:  22     ISSN:  1533-4287     ISO Abbreviation:  J Strength Cond Res     Publication Date:  2008 Jan 
Date Detail:
Created Date:  2008-02-25     Completed Date:  2008-04-07     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9415084     Medline TA:  J Strength Cond Res     Country:  United States    
Other Details:
Languages:  eng     Pagination:  66-74     Citation Subset:  IM    
The Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Chiba Prefecture, Japan.
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MeSH Terms
Analysis of Variance
Cohort Studies
DNA Damage / physiology*
Electromyography / methods
Exercise / physiology*
Exercise Tolerance / physiology
Hemodynamics / physiology
Hyperbaric Oxygenation*
Hyperoxia / physiopathology*
Muscle Contraction / physiology
Muscle Fatigue / physiology*
Oxidative Stress / physiology
Physical Exertion*
Reference Values
Sensitivity and Specificity

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

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