Submitted on October 9, 2006
Accepted on January 12, 2007
Long Term Estrogen Deficiency Lowers Regional Blood Flow, Resting Systolic Blood Pressure and Heart Rate in Exercising Premenopausal Women
Emma O'Donnell1, Paula J Harvey2, Jack M Goodman3, and Mary Jane De Souza1*
1 Women's Exercise and Bone Health Laboratory, Exercise Sciences, University of Toronto, Toronto, Canada
2 Division of Cardiology, Department of Medicine, University of Toronto, University Health Network and Mount Sinai Hospital, Toronto, Canada
3 Cardiovascular Research Laboratory, Exercise Sciences, University of Toronto, Toronto, Canada
* To whom correspondence should be addressed. E-mail: maryjane.desouza{at}utoronto.ca.
The cardiovascular consequences of hypoestrogenism in premenopausal women are unclear. Accordingly, the influence of menstrual status and endogenous estrogen (E2) exposure on blood pressure (BP), heart rate (HR), and calf blood flow in young (18-35yrs) regularly exercising premenopausal women with exercise-associated menstrual aberrations was investigated. Across consecutive menstrual cycles, daily urinary ovarian steroid levels were analyzed and the area under the curve calculated to determine menstrual status and E2 exposure. BP, HR, blood flow, vascular conductance and resistance were measured at baseline and following ischemic calf exercise. Exercising subjects consisted of 10 ovulatory (ExOv), 10 short term (anovulatory and 
100 days amenorrhea; ST-E2 Def), and 8 long-term (>100 days amenorrhea; LT-E2 Def) E2 deficient women. Nine sedentary ovulatory subjects (SedOv) were also studied. All groups were similar in age (24.8±0.7 yrs), height (164.8±1.3 cm), weight (57.9±0.9 kg) and BMI (21.3±0.3 kg/m2). E2 deficient groups had lower (p<0.002) E2 exposure compared with ovulatory groups. Resting systolic BP, HR, blood flow, and vascular conductance were lower (p<0.05), and vascular resistance higher (p<0.05) in LT-E2 Def compared with both ovulatory groups. Peak-ischemic blood flow, vascular conductance and HR were also lower (p<0.05), and vascular resistance higher (p<0.05) in LT-E2 Def compared with all other groups. Our findings show that exercising women with long term E2 deficiency have impaired regional blood flow and lower systolic BP and HR compared with exercising and sedentary ovulatory women. These cardiovascular alterations represent markers of altered vascular function and autonomic regulation of which the long-term effects remain unknown.
