title: The effect of hypoxia and work intensity on insulin resistance in type 2 diabetes.
abstract: BACKGROUND
  Hypoxia and muscle contraction stimulate glucose transport in vitro. We have previously demonstrated that exercise and hypoxia have an additive effect on insulin sensitivity in type 2 diabetics.
  
  
  OBJECTIVE
  Our objective was to examine the effects of three different hypoxic/exercise (Hy Ex) trials on glucose metabolism and insulin resistance in the 48 h after acute hypoxia in type 2 diabetics.
  
  
  METHODS
  Eight male type 2 diabetics completed 60 min of hypoxic [mean (sem) O(2) = ∼14.7 (0.2)%] exercise at 90% of lactate threshold [Hy Ex(60); 49 (1) W]. Patients completed an additional two hypoxic trials of equal work, lasting 40 min [Hy Ex(40); 70 (1) W] and 20 min [Hy Ex(20); 140 (12) W].
  
  
  METHODS
  Glucose rate of appearance and rate of disappearance were determined using the one-compartment minimal model. Homeostasis models of insulin resistance (HOMA(IR)), fasting insulin resistance index and β-cell function (HOMA(β-cell)) were calculated at 24 and 48 h after trials.
  
  
  RESULTS
  Peak glucose rate of appearance was highest during Hy Ex(20) [8.89 (0.56) mg/kg · min, P < 0.05]. HOMA(IR) and fasting insulin resistance index were improved in the 24 and 48 h after Hy Ex(60) and Hy Ex(40) (P < 0.05). HOMA(IR) decreased 24 h after Hy Ex(20) (P < 0.05) and returned to baseline values at 48 h.
  
  
  CONCLUSIONS
  Moderate-intensity exercise in hypoxia (Hy Ex(60) and Hy Ex(40)) stimulates acute- and moderate-term improvements in insulin sensitivity that were less apparent in Hy Ex(20). Results suggest that exercise duration and not total work completed has a greater influence on acute and moderate-term glucose control in type 2 diabetics.
authors: School of Life Sciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK. r.mackenzie@westminster.ac.uk
authors: R
authors: R
authors: Mackenzie
authors: B
authors: B
authors: Elliott
authors: N
authors: N
authors: Maxwell
authors: G
authors: G
authors: Brickley
authors: P
authors: P
authors: Watt
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D015444:Exercise / Q000502:physiology*; D005215:Fasting / Q000097:blood / Q000378:metabolism; D005951:Glucose Tolerance Test; D006801:Humans; D000860:Hypoxia / Q000150:complications / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion / Q000502:physiology; D016526:Workload
chemical_list: D001786:Blood Glucose