Document Detail

Substrate utilization during exercise and recovery at moderate altitude.
MedLine Citation:
PMID:  20036404     Owner:  NLM     Status:  MEDLINE    
Recent studies have shown that exercise training at moderate altitude or in moderate hypoxia improved glycemic parameters. From these data, it has been supposed that endurance exercise in moderate hypoxia affects substrate utilization and that exposure to moderate hypoxia in combination with exercise may be utilized as part of metabolic or diabetes prevention program. However, the influence of exercise at moderate hypoxia on circulating metabolites and hormones in terms of substrate utilization is unclear. The purpose of this study was to elucidate the influence of exercise in moderate hypoxia on substrate utilization. We determined cardiorespiratory, metabolic, and hormonal parameters during exercise and postexercise recovery at a simulated moderate altitude of 2000 m, and then we compared these variables with values obtained at sea level. Seven men participated in this study; subjects reported to the laboratory on 4 occasions. Two maximal exercise tests were performed to estimate peak oxygen uptake at the simulated 2000-m altitude and sea level on different days. Afterward, submaximal exercise tests were carried out at a simulated altitude of 2000 m or sea level, separated by 1 week. Subjects performed submaximal exercise at the same relative exercise intensity (50% peak oxygen uptake) at a simulated altitude of 2000 m and at sea level for 30 minutes. The tests were performed in random order, and subjects were blinded to the respective altitudes. Venous blood samples and expired gases were obtained before, during exercise (15 and 30 minutes), and during postexercise recovery periods (15, 30, 45, and 60 minutes). The respiratory exchange ratio during exercise and recovery at moderate altitude was greater than at sea level. The epinephrine and norepinephrine concentrations during exercise and recovery were higher (P < .05) at moderate altitude than at sea level. Free fatty acids and glycerol concentrations during recovery were lower (P < .05) at moderate altitude than at sea level. These results suggest that carbohydrate utilization is increased during exercise and postexercise recovery period in moderate hypoxia as compared with normoxia. It is also suggested that moderate hypoxia influences the changes in circulating metabolites and hormones in terms of substrate metabolism during exercise and the recovery.
Keisho Katayama; Kazushige Goto; Koji Ishida; Futoshi Ogita
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Publication Detail:
Type:  Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't     Date:  2009-12-29
Journal Detail:
Title:  Metabolism: clinical and experimental     Volume:  59     ISSN:  1532-8600     ISO Abbreviation:  Metab. Clin. Exp.     Publication Date:  2010 Jul 
Date Detail:
Created Date:  2010-06-07     Completed Date:  2010-06-17     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0375267     Medline TA:  Metabolism     Country:  United States    
Other Details:
Languages:  eng     Pagination:  959-66     Citation Subset:  IM    
Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan.
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MeSH Terms
Anaerobic Threshold / physiology
Anoxia / metabolism
Blood Glucose / metabolism
Carbon Dioxide / blood,  metabolism
Cardiovascular Physiological Phenomena
Epinephrine / blood
Exercise / physiology*
Fatty Acids, Nonesterified / blood
Glycerol / blood
Heart Rate / physiology
Human Growth Hormone / blood
Insulin / blood
Lactic Acid / blood
Metabolism / physiology*
Norepinephrine / blood
Oxygen Consumption
Pulmonary Gas Exchange / physiology
Respiratory Function Tests
Respiratory Mechanics / physiology
Young Adult
Reg. No./Substance:
0/Blood Glucose; 0/Fatty Acids, Nonesterified; 11061-68-0/Insulin; 124-38-9/Carbon Dioxide; 12629-01-5/Human Growth Hormone; 50-21-5/Lactic Acid; 51-41-2/Norepinephrine; 51-43-4/Epinephrine; 56-81-5/Glycerol

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

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