title: Impaired vascular function in physically active premenopausal women with functional hypothalamic amenorrhea is associated with low shear stress and increased vascular tone.
abstract: BACKGROUND
  Exercise-trained hypoestrogenic premenopausal women with functional hypothalamic amenorrhea (ExFHA) exhibit impaired endothelial function. The vascular effects of an acute bout of exercise, a potent nitric oxide stimulus, in these women are unknown.
  
  
  METHODS
  Three groups were studied: recreationally active ExFHA women (n = 12; 24.2 ± 1.2 years of age; mean ± SEM), and recreationally active (ExOv; n = 14; 23.5 ± 1.2 years of age) and sedentary (SedOv; n = 15; 23.1 ± 0.5 years of age) ovulatory eumenorrheic women. Calf blood flow (CBF) and brachial artery flow-mediated dilation (FMD) were evaluated using plethysmographic and ultrasound techniques, respectively, both before and 1 hour after 45 minutes of moderate-intensity exercise. Endothelium-independent dilation was assessed at baseline using glyceryl trinitrate. Calf vascular resistance (CVR) and brachial peak shear rate, as determined by the area under the curve (SRAUCpk), were also calculated.
  
  
  RESULTS
  FMD and glyceryl trinitrate responses were lower (P < .05) in ExFHA (2.8% ± 0.4% and 11.6% ± 0.7%, respectively) than ExOv (8.8% ± 0.7% and 16.7% ± 1.3%) and SedOv (8.0% ± 0.5% and 17.1% ± 1.8%). SRAUCpk was also lower (P < .05) in ExFHA. Normalization of FMD for SRAUCpk (FMD/SRAUCpk) did not alter (P > .05) the findings. CBF was lower (P < .05) and CVR higher (P < .05) in ExFHA. After exercise, FMD and SRAUCpk were augmented (P < .05), but remained lower (P < .05), in ExFHA. FMD/SRAUCpk no longer differed (P > .05) between the groups. CBF in ExFHA was increased (P < .05) and CVR decreased (P < .05) to levels observed in ovulatory women.
  
  
  CONCLUSIONS
  Acute dynamic exercise improves vascular function in ExFHA women. Although the role of estrogen deficiency per se is unclear, our findings suggest that low shear rate and increased vasoconstrictor tone may play a role in impaired basal vascular function in these women.
authors.affiliation: Cardiovascular Research Laboratory (E.O., J.M.G.), Department of Exercise Sciences, University of Toronto, Toronto, Ontario, M5S 2W6 Canada; Division of Cardiology (J.M.G., S.M.), Mt Sinai Hospital, Toronto, Ontario, M5G 1X5 Canada; and Division of Cardiology (P.J.H.), Women's College Hospital, Department of Medicine, University of Toronto, Ontario, M5S 1B2 Canada.
authors.forename: Emma
authors.initials: E
authors.lastname: O'Donnell
authors.forename: Jack M
authors.initials: JM
authors.lastname: Goodman
authors.forename: Susanna
authors.initials: S
authors.lastname: Mak
authors.forename: Paula J
authors.initials: PJ
authors.lastname: Harvey
mesh_terms: D000328:Adult; D000568:Amenorrhea / Q000503:physiopathology*; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000503:physiopathology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007027:Hypothalamic Diseases / Q000503:physiopathology*; D012039:Regional Blood Flow / Q000502:physiology; D013314:Stress, Mechanical; D014463:Ultrasonography