Document Detail


Cerebral and muscle deoxygenation, hypoxic ventilatory chemosensitivity and cerebrovascular responsiveness during incremental exercise.
MedLine Citation:
PMID:  19729079     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
To examine if cerebral (frontal cortex) and skeletal muscle (m. vastus lateralis) deoxygenation and cerebral blood flow velocity (V(mean)) in the middle cerebral artery differentiated between normoxic and hypoxic (end-tidal P(O)(2) 71 mmHg) conditions, and if they were associated with hypoxic ventilatory chemosensitivity and cerebrovascular responsiveness, 8 men performed incremental cycling trials (30W/min ramp) under normoxic (T1-N) and hypoxic (T1-H) conditions until volitional fatigue, or until arterial O2 saturation decreased below 80%. The tests were repeated (T2-N; T2-H) on another day with supplemental O2 (Sup-O2) at the end of exercise. The V(mean) response was similar in normoxia and hypoxia. In hypoxia compared to normoxia, cerebral deoxygenation ( upward arrow deoxyhemoglobin concentration (Delta[HHb]) and downward arrow tissue oxygenation index (TOI)) was greater at a given work rate. A strong hypoxic ventilatory chemosensitivity was associated with a rapid reduction of cerebral TOI (r=0.94, P<0.001). Muscle deoxygenation was similar in normoxia and hypoxia suggesting greater muscle blood flow in hypoxia compared to normoxia and thus the existence of control features that match muscle perfusion and O2 delivery tightly with O2 demand during exercise. Sup-O2 reduced both cerebral and muscle deoxygenation, at least transiently.
Authors:
Juha E Peltonen; Donald H Paterson; J Kevin Shoemaker; Darren S Delorey; Gregory R Dumanoir; Robert J Petrella; John M Kowalchuk
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-09-01
Journal Detail:
Title:  Respiratory physiology & neurobiology     Volume:  169     ISSN:  1878-1519     ISO Abbreviation:  Respir Physiol Neurobiol     Publication Date:  2009 Oct 
Date Detail:
Created Date:  2009-10-05     Completed Date:  2009-12-09     Revised Date:  2010-01-26    
Medline Journal Info:
Nlm Unique ID:  101140022     Medline TA:  Respir Physiol Neurobiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  24-35     Citation Subset:  IM    
Affiliation:
Unit for Sports and Exercise Medicine, Institute of Clinical Medicine, University of Helsinki, Paasikivenkatu 4, 00250 Helsinki, Finland. juha.peltonen@helsinki.fi
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MeSH Terms
Descriptor/Qualifier:
Adult
Anoxia / pathology*,  physiopathology
Blood Flow Velocity / physiology
Blood Pressure / physiology
Cerebral Cortex / blood supply,  physiopathology*
Cerebrovascular Circulation / physiology*
Exercise / physiology*
Hemoglobins / metabolism
Humans
Male
Muscle Fatigue / physiology
Muscle, Skeletal / blood supply,  physiopathology*
Oxygen / blood
Oxygen Consumption / physiology
Pulmonary Ventilation / physiology*
Respiratory Function Tests
Spectroscopy, Near-Infrared
Young Adult
Chemical
Reg. No./Substance:
0/Hemoglobins; 7782-44-7/Oxygen

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


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