Low-dose estrogen therapy does not change postexercise hypotension, sympathetic nerve activity reduction, and vasodilation in healthy postmenopausal women.
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 x min(-1) x 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.
Oneda
Bruna
B
Hypertension Unit, General Hospital, University of São Paulo, São Paulo, Brazil.
Forjaz
Claudia L M
CL
Bernardo
Fernanda R
FR
Araújo
Tatiana G
TG
Gusmão
Josiane L
JL
Labes
Eliana
E
Abrahão
Sandra B
SB
Mion
Decio
D
Fonseca
Angela M
AM
Tinucci
Tais
T
D000284:Administration, Oral; D001794:Blood Pressure / Q000187:drug effects; D004958:Estradiol / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D015914:Estrogen Replacement Therapy / Q000009:adverse effects; D015444:Exercise; D005260:Female; D005542:Forearm / Q000098:blood supply*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007022:Hypotension / Q000139:chemically induced / Q000503:physiopathology*; D007044:Hysterectomy; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation*; D017698:Postmenopause; D012039:Regional Blood Flow / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000503:physiopathology; D014655:Vascular Resistance / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects*
D004958:Estradiol