title: Impact of exercise on diurnal and nocturnal markers of glycaemic variability and oxidative stress in obese individuals with type 2 diabetes or impaired glucose tolerance.
abstract: OBJECTIVE
  We measured the effects of a single bout of exercise on diurnal and nocturnal oxidative stress and glycaemic variability in obese subjects with type 2 diabetes mellitus or impaired glucose tolerance versus obese healthy controls.
  
  
  METHODS
  Subjects (in random order) performed either a single 30-min bout of moderate-intensity exercise or remained sedentary for 30 min at two separate visits. To quantify glycaemic variability, standard deviation of glucose (measured by continuous glucose monitoring system) and continuous overlapping net glycaemic action of 1-h intervals (CONGA-1) were calculated for three 12-h intervals during each visit. Oxidative stress was measured by 15-isoprostane F(2t) levels in urine collections for matching 12-h intervals.
  
  
  RESULTS
  Exercise reduced daytime glycaemic variability (ΔCONGA-1 = -12.62 ± 5.31 mg/dL, p = 0.04) and urinary isoprostanes (ΔCONGA-1 = -0.26 ± 0.12 ng/mg, p = 0.04) in the type 2 diabetes mellitus/impaired glucose tolerance group. Daytime exercise-induced change in urinary 15-isoprostane F(2t) was significantly correlated with both daytime standard deviation (r = 0.68, p = 0.03) and with subsequent overnight standard deviation (r = 0.73, p = 0.027) in the type 2 diabetes mellitus/impaired glucose tolerance group.
  
  
  CONCLUSIONS
  Exercise significantly impacts the relationship between diurnal oxidative stress and nocturnal glycaemic variability in individuals with type 2 diabetes mellitus/impaired glucose tolerance.
authors.affiliation: Center for Narcolepsy, Sleep and Health Research, University of Illinois at Chicago, Chicago, IL, USA Department of Biobehavioral Health Science, University of Illinois at Chicago, Chicago, IL, USA sschwa24@uic.edu.
authors.forename: Sarah S
authors.initials: SS
authors.lastname: Farabi
authors.affiliation: Center for Narcolepsy, Sleep and Health Research, University of Illinois at Chicago, Chicago, IL, USA Department of Biobehavioral Health Science, University of Illinois at Chicago, Chicago, IL, USA Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Carley
authors.affiliation: Cadence Cancer Center, Warrenville, IL, USA.
authors.forename: Donald
authors.initials: D
authors.lastname: Smith
authors.affiliation: Department of Biobehavioral Health Science, University of Illinois at Chicago, Chicago, IL, USA.
authors.forename: Lauretta
authors.initials: L
authors.lastname: Quinn
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000188:drug therapy / Q000378:metabolism*; D015444:Exercise / Q000502:physiology*; D005260:Female; D018149:Glucose Intolerance / Q000378:metabolism*; D006801:Humans; D006943:Hyperglycemia / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D001786:Blood Glucose
keywords: Glycaemic variability; exercise; oxidative stress; type 2 diabetes