Document Detail

Effects of acute hypoxia at moderate altitude on stroke volume and cardiac output during exercise.
MedLine Citation:
PMID:  20558906     Owner:  NLM     Status:  MEDLINE    
It has been unclear how acute hypoxia at moderate altitude affects stroke volume (SV), an index of cardiac function, during exercise. The present study was conducted to reveal whether acute normobaric hypoxia might alter SV during exercise.Nine healthy male subjects performed maximal exercise testing under normobaric normoxic, and normobaric hypoxic conditions (O(2): 14.4%) in a randomized order. A novel thoracic impedance method was used to continuously measure SV and cardiac output (CO) during exercise. Acute hypoxia decreased maximal work rate (hypoxia; 247 + or - 6 [SE] versus normoxia; 267 + or - 8 W, P < 0.005) and VO(2) max (hypoxia; 2761 + or - 99 versus normoxia; 3039 + or - 133 mL/min, P < 0.005). Under hypoxic conditions, SV and CO at maximal exercise decreased (SV: hypoxia; 145 + or - 11 versus normoxia; 163 + or - 11 mL, P < 0.05, CO: hypoxia; 26.7 + or - 2.1 versus normoxia; 30.2 + or - 1.8 L/min, P < 0.05). In acute hypoxia, SV during submaximal exercise at identical work rate decreased. Furthermore, in hypoxia, 4 of 9 subjects attained their highest SV at maximal exercise, while in normoxia, 8 of 9 subjects did.Acute normobaric hypoxia attenuated the increment of SV and CO during exercise, and SV reached a plateau earlier under hypoxia than in normoxia. Cardiac function during exercise at this level of acute normobaric hypoxia might be attenuated.
Taira Fukuda; Taketeru Maegawa; Akihiro Matsumoto; Yutaka Komatsu; Toshiaki Nakajima; Ryozo Nagai; Takashi Kawahara
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Publication Detail:
Type:  Journal Article; Randomized Controlled Trial    
Journal Detail:
Title:  International heart journal     Volume:  51     ISSN:  1349-2365     ISO Abbreviation:  Int Heart J     Publication Date:  2010 May 
Date Detail:
Created Date:  2010-06-18     Completed Date:  2010-09-28     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101244240     Medline TA:  Int Heart J     Country:  Japan    
Other Details:
Languages:  eng     Pagination:  170-5     Citation Subset:  IM    
Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
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MeSH Terms
Acute Disease
Anoxia / etiology,  physiopathology*
Blood Pressure / physiology
Cardiography, Impedance
Exercise / physiology*
Heart Rate / physiology
Oxygen Consumption / physiology
Physical Endurance / physiology
Reproducibility of Results
Stroke Volume / physiology*

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