Abstract 15561: Abnormal Vascular Function in Physically Active Estrogen Deficient Premenopausal Women is not Rectified by Acute Dynamic Exercise

Abstract

Background: One mechanism by which regular exercise may exact cardiovascular protection is by improving endothelial function. However, exercise-trained estrogen deficient premenopausal women with functional hypothalamic amenorrhea (ExFHA) exhibit impaired endothelial function.

Hypothesis: We hypothesized that in women with ExFHA a single bout of dynamic exercise, a nitric oxide stimulus, would acutely augment endothelial function.

Methods: Three groups were studied: recreationally active (ExOv; n=13; aged 22±1years; body mass index 21.3±0.6 kg/m²; mean±SEM) and sedentary (SedOv; n=16; 23±1yrs; 21.7±0.5 kg/m²) eumenorrheic ovulatory women, and women with ExFHA (n=11; aged 24±1 years; 20.4±0.8 kg/m²). Measures of blood pressure (BP; mmHg), heart rate (HR; beats/min), and flow mediated vasodilation (FMD%) were obtained at baseline, and 60 minutes after 45 minutes of moderate aerobic exercise. Endothelium-independent nitroglycerin-mediated vasodilation (EID%) was assessed only at baseline to avoid hypotensive responses to nitroglycerin post-exercise.

Results: In ExFHA, baseline HR (47±3), systolic BP (92±2) and pulse pressure (35±2; mmHg) were lower (p<0.05) than in ExOv (55±2, 102±2, and 43±2) and SedOv (60±2,100±2, and 44±2) women. Baseline brachial artery diameters were similar (p>0.05) in all groups, but both FMD% and EID% were lower (p<0.05) in ExFHA (2.8±0.4 and 11.6±0.7) compared with ExOv (8.9±0.7 and 16.7±1.3) and SedOv (7.7±0.6 and 16.9±1.8). Post-exercise, FMD% was augmented in ExFHA women (5.7±0.8; p<0.05), but was unchanged (p>0.05) in ExOv and SedOv women. However, FMD% post-exercise remained significantly lower (p<0.05) in the ExFHA group. Using pooled data, pulse pressure (r=0.564, p<0.05) and serum estradiol (r=0.404, p<0.05) were correlated with baseline FMD% but not EID%.

Conclusion: Despite both regular aerobic exercise conditioning and premenopausal status, women with ExFHA have abnormalities in endothelial and smooth muscle cell responsiveness, and impaired FMD% that is incompletely restored by dynamic exercise. Given that endothelial dysfunction may precede atherosclerosis, long term observational investigations in these otherwise healthy premenopausal women are warranted.