title: Impact of exercise and moderate hypoxia on glycemic regulation and substrate oxidation pattern.
abstract: OBJECTIVE
  We examined metabolic and endocrine responses during rest and exercise in moderate hypoxia over a 7.5 h time courses during daytime.
  
  
  METHODS
  Eight sedentary, overweight men (28.6 ± 0.8 kg/m2) completed four experimental trials: a rest trial in normoxia (FiO2 = 20.9%, NOR-Rest), an exercise trial in normoxia (NOR-Ex), a rest trial in hypoxia (FiO2 = 15.0%, HYP-Rest), and an exercise trial in hypoxia (HYP-Ex). Experimental trials were performed from 8:00 to 15:30 in an environmental chamber. Blood and respiratory gas samples were collected over 7.5 h. In the exercise trials, subjects performed 30 min of pedaling exercise at 60% of VO2max at 8:00, 10:30, and 13:00, and rested during the remaining period in each environment. Standard meals were provided at 8:30, 11:00, and 13:30.
  
  
  RESULTS
  The areas under the curves for blood glucose and serum insulin concentrations over 7.5 h did not differ among the four trials. At baseline, %carbohydrate contribution was significantly higher in the hypoxic trials than in the normoxic trials (P<0.05). Although exercise promoted carbohydrate oxidation in the NOR-Ex and HYP-Ex trials, %carbohydrate contribution during each exercise and post-exercise period were significantly higher in the HYP-Ex trial than in the NOR-Ex trial (P<0.05).
  
  
  CONCLUSIONS
  Three sessions of 30 min exercise (60% of VO2max) in moderate hypoxia over 7.5 h did not attenuate postprandial glucose and insulin responses in young, overweight men. However, carbohydrate oxidation was significantly enhanced when the exercise was conducted in moderate hypoxia.
authors.affiliation: Graduate School of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Morishima
authors.affiliation: Graduate School of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan.
authors.forename: Ayaka
authors.initials: A
authors.lastname: Mori
authors.affiliation: Graduate School of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Sasaki
authors.affiliation: Graduate School of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan; Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan.
authors.forename: Kazushige
authors.initials: K
authors.lastname: Goto
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D015444:Exercise; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005990:Glycerol / Q000097:blood; D006339:Heart Rate; D006801:Humans; D000860:Hypoxia / Q000097:blood / Q000378:metabolism*; D007328:Insulin / Q000097:blood; D019344:Lactic Acid / Q000097:blood; D008297:Male; D050177:Overweight / Q000097:blood / Q000378:metabolism / Q000503:physiopathology; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D019518:Postprandial Period; D012146:Rest
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D019344:Lactic Acid; D005990:Glycerol; D010100:Oxygen