title: Sex differences in the effects of type 2 diabetes on exercise performance.
abstract: OBJECTIVE
  People with uncomplicated type 2 diabetes (T2D) have impaired peak exercise performance compared with that of their nondiabetic counterparts. This impairment may represent the earliest indication of cardiovascular (CV) abnormalities in T2D. Women with T2D are known to have worse CV outcomes than those in men with T2D. We hypothesized that women with diabetes have a greater exercise impairment than that in men with diabetes compared with that in their nondiabetic counterparts.
  
  
  METHODS
  We studied 15 women (premenopausal) and 14 men with T2D as well as their nondiabetic counterparts (22 women and 13 men). Exercise testing was performed. Additional outcomes included measurements of insulin sensitivity, endothelial function, blood flow, and resting cardiac function.
  
  
  RESULTS
  Men and women with T2D but not controls had impaired insulin sensitivity. Women with T2D had a lower peak oxygen consumption (V˙O2peak) compared with that of nondiabetic women (24%, P < 0.05) than men with diabetes compared with that in nondiabetic men (16%, P < 0.05) (P value between groups < 0.05). The time constants (phase 2) of the V˙O2 kinetic response tended to be slower in men and women with T2D than those in nondiabetic controls (P = 0.08). There were no differences in resting ventricular function by Doppler echocardiography techniques between groups. Women with T2D had significantly lower flow-mediated dilation and blood flow responses to hyperemia than those in nondiabetic women (both P < 0.05), whereas men with T2D had lower flow-mediated dilation but not lower blood flow than those in nondiabetic men.
  
  
  CONCLUSIONS
  Although both men and women with uncomplicated T2D had a lower V˙O2peak, the abnormality in women with T2D compared with that in nondiabetic women was greater than that seen in men. Because V˙O2peak has a strong inverse correlation with mortality, sex disparities observed in exercise capacity among people with T2D suggest a possible rationale for the increased CV morbidity and mortality observed in women compared with those observed in men with uncomplicated T2D.
authors.affiliation: 1Department of Medicine, Division of Internal Medicine, University of Colorado School of Medicine, Aurora, CO; 2Department of Medicine, Division of Cardiology, University of Colorado School of Medicine, Aurora, CO; 3Department of Medicine, Center for Women's Health Research, University of Colorado School of Medicine, Aurora, CO; 4Division of Endocrinology, University of Colorado School of Medicine, Aurora, CO; 5Department of Medicine, Division of Cardiology, National Jewish Health, Denver, CO; and 6Denver Veterans Affairs Medical Center, Denver, CO.
authors.forename: Judith G
authors.initials: JG
authors.lastname: Regensteiner
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Bauer
authors.forename: Amy G
authors.initials: AG
authors.lastname: Huebschmann
authors.forename: Leah
authors.initials: L
authors.lastname: Herlache
authors.forename: Howard D
authors.initials: HD
authors.lastname: Weinberger
authors.forename: Eugene E
authors.initials: EE
authors.lastname: Wolfel
authors.forename: Jane E B
authors.initials: JE
authors.lastname: Reusch
mesh_terms: D000328:Adult; D001916:Brachial Artery / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D015150:Echocardiography, Doppler; D004727:Endothelium / Q000503:physiopathology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D005542:Forearm / Q000098:blood supply; D064368:Healthy Volunteers; D006801:Humans; D007333:Insulin Resistance; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D011930:Reaction Time / Q000502:physiology; D012039:Regional Blood Flow; D012737:Sex Factors; D014664:Vasodilation; D016276:Ventricular Function