Low-dose estrogen therapy does not change postexercise hypotension, sympathetic nerve activity reduction, and vasodilation in healthy postmenopausal women

• Published in: American journal of physiology. Heart and circulatory physiology Vol. 295; no. 4; pp. H1802 - H1808
• Main Authors: Oneda, Bruna, Forjaz, Claudia L. M, Bernardo, Fernanda R, Araujo, Tatiana G, Gusmao, Josiane L, Labes, Eliana, Abrahao, Sandra B, Mion, Decio, Jr, Fonseca, Angela M, Tinucci, Tais
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 01.10.2008
• Subjects: Administration, Oral; Blood pressure; Blood Pressure - drug effects; Estradiol - administration & dosage; Estradiol - adverse effects; Estradiol - analogs & derivatives; Estrogen Replacement Therapy - adverse effects; Estrogens; Exercise; Female; Forearm - blood supply; Heart rate; Heart Rate - drug effects; Humans; Hypotension - chemically induced; Hypotension - physiopathology; Hysterectomy; Menopause; Middle Aged; Muscle, Skeletal - innervation; Postmenopause; Regional Blood Flow - drug effects; Studies; Sympathetic Nervous System - drug effects; Sympathetic Nervous System - physiopathology; Therapy; Vascular Resistance - drug effects; Vasodilation - drug effects
• ISSN: 0363-6135; 1522-1539
• DOI: 10.1152/ajpheart.01222.2007

1 Hypertension Unit, General Hospital, University of São Paulo; 2 Exercise Hemodynamic Laboratory, School of Physical Education and Sport, University of São Paulo; and 3 Gynecology and Climacteric Service, General Hospital, University of São Paulo, São Paulo, Brazil Submitted 22 October 2007 ; accepted in final form 29 August 2008 The aim of this study was to determine whether estrogen therapy enhances postexercise muscle sympathetic nerve activity (MSNA) decrease and vasodilation, resulting in a greater postexercise hypotension. Eighteen postmenopausal women received oral estrogen therapy (ET; n = 9, 1 mg/day) or placebo ( n = 9) for 6 mo. They then participated in one 45-min exercise session (cycle ergometer at 50% of oxygen uptake peak) and one 45-min control session (seated rest) in random order. Blood pressure (BP, oscillometry), heart rate (HR), MSNA (microneurography), forearm blood flow (FBF, plethysmography), and forearm vascular resistance (FVR) were measured 60 min later. FVR was calculated. Data were analyzed using a two-way ANOVA. Although postexercise physiological responses were unaltered, HR was significantly lower in the ET group than in the placebo group (59 ± 2 vs. 71 ± 2 beats/min, P < 0.01). In both groups, exercise produced significant decreases in systolic BP (145 ± 3 vs. 154 ± 3 mmHg, P = 0.01), diastolic BP (71 ± 3 vs. 75 ± 2 mmHg, P = 0.04), mean BP (89 ± 2 vs. 93 ± 2 mmHg, P = 0.02), MSNA (29 ± 2 vs. 35 ± 1 bursts/min, P < 0.01), and FVR (33 ± 4 vs. 55 ± 10 units, P = 0.01), whereas it increased FBF (2.7 ± 0.4 vs. 1.6 ± 0.2 ml·min –1 ·100 ml –1 , P = 0.02) and did not change HR (64 ± 2 vs. 65 ± 2 beats/min, P = 0.3). Although ET did not change postexercise BP, HR, MSNA, FBF, or FVR responses, it reduced absolute HR values at baseline and after exercise. postmenopause; aerobic exercise; muscle sympathetic nerve activity; blood pressure Address for reprint requests and other correspondence: T. Tinucci, Av. Prof. Mello Moraes, 65, Butantã, São Paulo, SP 05508-030, Brazil (e-mail: ttinucci{at}usp.br )