Document Detail


Nervous system function during exercise in hypoxia.
MedLine Citation:
PMID:  19555297     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Aerobic exercise capacity decreases with exposure to hypoxia. This article focuses on the effects of hypoxia on nervous system function and the potential consequences for the exercising human. Emphasis is put on somatosensory muscle afferents due to their crucial role in the reflex inhibition of muscle activation and in cardiorespiratory reflex control during exercise. We review the evidence of hypoxia influences on muscle afferents and discuss important consequences for exercise performance. Efferent (motor) nerves are less affected at altitude and are thought to stay fairly functional even in severe levels of arterial hypoxemia. Altitude also alters autonomic nervous system functions, which are thought to play an important role in the regulation of cardiac output and ventilation. Finally, the consequences of hypoxia-induced cortical adaptations and dysfunctions are evaluated in terms of neurotransmitter turnover, brain electrical activity, and cortical excitability. Even though the cessation of exercise or the reduction of exercise intensity, when reaching maximum performance, implies reduced motor recruitment by the nervous system, the mechanisms that lead to the de-recruitment of active muscle are still not well understood. In moderate hypoxia, muscle afferents appear to play an important role, whereas in severe hypoxia brain oxygenation may play a more important role.
Authors:
Markus Amann; Bengt Kayser
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Review    
Journal Detail:
Title:  High altitude medicine & biology     Volume:  10     ISSN:  1557-8682     ISO Abbreviation:  High Alt. Med. Biol.     Publication Date:  2009  
Date Detail:
Created Date:  2009-06-26     Completed Date:  2009-09-29     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901183     Medline TA:  High Alt Med Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  149-64     Citation Subset:  IM; S    
Affiliation:
University of Zürich , Institute of Physiology, and ETH Zürich, Exercise Physiology, Zürich, Switzerland. markus.amann@utah.edu
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MeSH Terms
Descriptor/Qualifier:
Anoxia / physiopathology*
Blood Pressure / physiology
Brain / metabolism
Cerebral Cortex / physiology
Exercise / physiology*
Heart Rate / physiology
Humans
Muscle Contraction / physiology
Muscle Fatigue / physiology
Muscle Fibers, Skeletal / physiology
Muscle, Skeletal / innervation,  physiology
Nervous System Physiological Phenomena*
Neurons / physiology
Neurotransmitter Agents / metabolism
Oxygen / metabolism
Pulmonary Ventilation / physiology
Chemical
Reg. No./Substance:
0/Neurotransmitter Agents; 7782-44-7/Oxygen

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


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