Document Detail

Cerebral metabolism is influenced by muscle ischaemia during exercise in humans.
MedLine Citation:
PMID:  12621535     Owner:  NLM     Status:  MEDLINE    
Maximal exercise reduces the cerebral metabolic ratio (O2/(glucose + 1/2 lactate)) to < 4 from a resting value close to 6, and only part of this decrease is explained by the 'intent' to exercise. This study evaluated whether sensory stimulation of brain by muscle ischaemia would reduce the cerebral metabolic ratio. In 10 healthy human subjects the cerebral arterial-venous differences (a-v differences) for O2, glucose and lactate were assessed before, during and after three bouts of 10 min cycling with equal workload: (1) control exercise at light intensity, (2) exercise that elicited a high rating of perceived exertion due to a 100 mmHg thigh cuff, and (3) exercise followed by 5 min of post-exercise muscle ischaemia that increased blood pressure by approximately 20 %. Control exercise did not significantly affect the a-v differences. However, during the recovery from exercise with thigh cuffs the cerebral metabolic ratio decreased from a resting value of 5.4 +/- 0.2 to 4.0 +/- 0.4 (mean +/- S.E.M.; P < 0.05) as a discrete lactate efflux from the brain at rest shifted to a slight uptake. Also, following post-exercise muscle ischaemia, the cerebral metabolic ratio decreased to 4.5 +/- 0.3 (P < 0.05). The results support the hypothesis that during exercise, cerebral metabolism is influenced both by the mental effort to exercise and by sensory input from skeletal muscles.
Mads K Dalsgaard; Lars Nybo; Yan Cai; Niels H Secher
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Experimental physiology     Volume:  88     ISSN:  0958-0670     ISO Abbreviation:  Exp. Physiol.     Publication Date:  2003 Mar 
Date Detail:
Created Date:  2003-03-06     Completed Date:  2003-10-23     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9002940     Medline TA:  Exp Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  297-302     Citation Subset:  IM    
Department of Anaesthesia and The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Denmark.
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MeSH Terms
Blood Glucose / metabolism
Brain / metabolism*
Exercise / physiology*
Ischemia / metabolism*
Lactic Acid / blood
Muscle, Skeletal / blood supply*
Oxygen / blood
Reg. No./Substance:
0/Blood Glucose; 50-21-5/Lactic Acid; 7782-44-7/Oxygen

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

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