Document Detail


Altitude acclimatization attenuates plasma ammonia accumulation during submaximal exercise.
MedLine Citation:
PMID:  3308809     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study examined the effects of acclimatization to 4,300 m altitude on changes in plasma ammonia concentrations with 30 min of submaximal [75% maximal O2 uptake (VO2max)] cycle exercise. Human test subjects were divided into a sedentary (n = 6) and active group (n = 5). Maximal uptake (VO2max) was determined at sea level and at high altitude (HA; 4,300 m) after acute (t less than 24 h) and chronic (t = 13 days) exposure. The VO2max of both groups decreased 32% with acute HA when compared with sea level. In the sedentary group, VO2max decreased an additional 16% after 13 days of continuous residence at 4,300 m, whereas VO2max in the active group showed no further change. In both sedentary and active subjects, plasma ammonia concentrations were increased (P less than 0.05) over resting levels immediately after submaximal exercise at sea level as well as during acute HA exposure. With chronic HA exposure, the active group showed no increase in plasma ammonia immediately after submaximal exercise, whereas the postexercise ammonia in the sedentary group was elevated but to a lesser extent than at sea level or with acute HA exposure. Thus postexercise plasma ammonia concentration was decreased with altitude acclimatization when compared with ammonia concentrations following exercise performed at the same relative intensity at sea level or acute HA. This decrease in ammonia accumulation may contribute to enhanced endurance performance and altered substrate utilization with exercise following acclimatization to altitude.
Authors:
P M Young; P B Rock; C S Fulco; L A Trad; V A Forte; A Cymerman
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  63     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1987 Aug 
Date Detail:
Created Date:  1987-11-09     Completed Date:  1987-11-09     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  758-64     Citation Subset:  IM; S    
Affiliation:
Altitude Research Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts 01760.
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MeSH Terms
Descriptor/Qualifier:
Acclimatization*
Adult
Altitude*
Ammonia / blood*
Blood Glucose / analysis
Fatty Acids, Nonesterified / blood
Glycerol / blood
Humans
Insulin / blood
Lactates / blood
Lactic Acid
Male
Oxygen Consumption
Physical Exertion*
Chemical
Reg. No./Substance:
0/Blood Glucose; 0/Fatty Acids, Nonesterified; 0/Insulin; 0/Lactates; 50-21-5/Lactic Acid; 56-81-5/Glycerol; 7664-41-7/Ammonia

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