title: Effect of exercise intensity and duration on capillary glucose responses in pregnant women at low and high risk for gestational diabetes.
abstract: BACKGROUND
  Exercise may influence glucose metabolism during pregnancy. We examined the effect of exercise intensity and duration on capillary glucose responses in pregnant women at low and high risk for gestational diabetes mellitus (GDM) who followed a modified GDM meal plan.
  
  
  METHODS
  Randomization occurred at study entry (16-20 weeks' gestation) into a low-intensity [30% heart rate reserve, low risk-30%I, n = 12; high risk-30%I, n = 11] or vigorous-intensity (70% heart rate reserve, low risk-70%I, n = 12; R-70%I, n = 11) exercise program with similar nutritional control. Exercise consisted of walking three to four times a week, gradually increasing time from 25 to 40 min/session. Free-living capillary glucose concentrations were measured once a week pre-exercise and post-exercise.
  
  
  RESULTS
  Capillary glucose responses to exercise were strongly influenced by an interaction between GDM risk, exercise duration and exercise intensity (p = 0.006). Decreases in glucose concentrations were observed after 25 (4 ± 13%), 35 (21 ± 12%) and 40 min (15 ± 18%) of walking in high risk-30%I women, with the most noticeable decline after 35 and 40 min. In the high risk-70%I, glucose concentrations decreased significantly only after 25 (22 ± 14%) and 35 min (7 ± 23%) and increasing the exercise time attenuated glucose concentrations decline. In low risk women, regardless of exercise intensity and duration, decreases in glucose concentrations were significant and similar.
  
  
  CONCLUSIONS
  To achieve the best decline in glucose concentrations, pregnant women who follow a modified GDM meal plan should walk for 25 min/session at vigorous intensity or for 35-40 min/session at low intensity if they are at risk for GDM and for at least 25 min at either low or vigorous intensity if they are at low risk for GDM.
authors.affiliation: R. Samuel McLaughlin Foundation-Exercise and Pregnancy Laboratory, School of Kinesiology, The University of Western Ontario, London, Canada. sruchat@uwo.ca
authors.forename: S-M
authors.initials: SM
authors.lastname: Ruchat
authors.forename: M H
authors.initials: MH
authors.lastname: Davenport
authors.forename: I
authors.initials: I
authors.lastname: Giroux
authors.forename: M
authors.initials: M
authors.lastname: Hillier
authors.forename: A
authors.initials: A
authors.lastname: Batada
authors.forename: M M
authors.initials: MM
authors.lastname: Sopper
authors.forename: R
authors.initials: R
authors.lastname: McManus
authors.forename: J-A
authors.initials: JA
authors.lastname: Hammond
authors.forename: M F
authors.initials: MF
authors.lastname: Mottola
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D002196:Capillaries / Q000378:metabolism*; D016640:Diabetes, Gestational / Q000178:diet therapy / Q000209:etiology / Q000503:physiopathology*; D004032:Diet; D015444:Exercise / Q000502:physiology*; D005260:Female; D005947:Glucose; D006801:Humans; D011247:Pregnancy; D012306:Risk; D016138:Walking
chemical_list: D001786:Blood Glucose; D005947:Glucose