Lack of effect of estrogen on rest and treadmill exercise in postmenopausal women without known cardiac disease

Associations Between Heart Rate Recovery Dynamics With Estradiol Levels in 20 to 60 Year-Old Sedentary Women

It is hypothesized that estradiol levels, as well as aging, influence cardiac autonomic function in women. The main aim of this study was to test the correlations between heart rate recovery (HRR) dynamics, as a proxy of cardiac autonomic function, with estradiol levels and age in women. This cross-sectional study involved 44 healthy women. Heart rate (HR) data were obtained beat-by-beat during the entire experiment. Maximal incremental exercise testing (IET) on a cycle ergometer was performed followed by 6 min of recovery. During the IET recovery period, the overall HRR dynamics were evaluated by exponential data modeling (time constant "τ") where shorter τ indicates faster HRR adjustment. Considering the cardiac autonomic complexity, HRR dynamics were also evaluated by delta (Δ) analysis considering different HR data intervals. The relationship between HRR dynamics, estradiol levels and age was tested by Pearson product-moment correlation. The overall HRR dynamics (i.e., τ) were statistically correlated with age (r = 0.58, p < 0.001) and estradiol levels (r = -0.37, p = 0.01). The Δ analysis showed that the slower overall HRR associated with aging was a consequence of slower dynamics occurring within the 45-210 s interval, indicating slower sympathetic withdrawal. In conclusion, aging effects on HRR in women seems to be correlated with a slower sympathetic withdrawal. In addition, the cardioprotective effect previously associated with estradiol seems not to influence the autonomic modulation during exercise recovery periods in women.

Maximal and submaximal aerobic fitness in postmenopausal women: influence of hormone-replacement therapy

The purpose of this study was to examine whether maximal and submaximal aerobic fitness parameters (peak oxygen consumption and ventilatory threshold, respectively) are affected by hormone-replacement therapy (HRT) in moderately active postmenopausal women. Forty healthy, active, postmenopausal women (21 taking HRT, mean age 62 ± 5 years; 19 not taking HRT, mean age 62 ± 7 years) met the peak oxygen consumption criteria during a cycle ergometer test (15 W ramp) and achieved volitional fatigue. Breath-by-breath measurement was used to determine peak oxygen consumption and to estimate ventilatory threshold. There were no differences in characteristics (age, body mass, height, body mass index, leisure-time physical activity) between the non-HRT and HRT groups, nor were there any differences in responses to maximal exercise, with an observed peak oxygen consumption (mL·kg–1·min–1) of 22.9 ± 3.8 in the non-HRT group and 22.0 ± 4.7 in the HRT group. There was also no difference in submaximal aerobic capacity, with ventilatory threshold values (mL·kg–1·min–1) of 16.7 ± 3.4 in the non-HRT group and 15.6 ± 3.2 in the HRT group. In a sample of healthy moderately active postmenopausal women, there was no difference in maximal or submaximal aerobic fitness parameters beteen the HRT and non-HRT groups.

Effect of Hormone Therapy on Exercise Capacity in Early Postmenopausal Women

OBJECTIVE

To compare the exercise capacity of postmenopausal women with matched premenopausal controls, as well as postmenopausal women before and after 3 months of hormone therapy (HT).

METHODS

This study examined the response to strenuous isotonic exercise in 30 women with recently developed menopause (age, mean+/-standard deviation, 50.6+/-1.1 years) without cardiovascular risk factors or diseases. Thirty premenopausal subjects, matched one-to-one for age and biophysical characteristics, were the control group. Postmenopausal women underwent examination before (T(0)) and 3 months after (T(1)) HT (oral 0.625 mg conjugated estrogen and 2.5 mg medroxyprogesterone acetate/day) with high-resolution ultrasound determination of peripheral flow-mediated vasodilation and an integrative cardiopulmonary test.

RESULTS

Postmenopausal women showed an impairment of flow-mediated vasodilation (P<.001) in the radial artery and a worsening of physical performance, primarily exemplified by lower maximal workload (P<.01) and peak oxygen consumption (Vo(2)max, P<.001) compared with premenopausal women. After 3 months on HT, ergometabolic parameters and vasodilation reserve were at a level comparable to premenopausal women. Flow-mediated vasodilation measurements after 3 months on HT significantly correlated with those of peak oxygen consumption (r=0.77, P<.001) and the ratio between the increase in oxygen consumption and that in work rate (DeltaVo(2)/DeltaWR) (r=0.73, P<.001).

CONCLUSION

The peripheral circulation is the limiting system in postmenopausal women experiencing exercise intolerance, and there are benefits in introducing HT.

Emerging Selective Estrogen Receptor Modulators

Menopause, regardless of age at onset, is associated with a marked increase in coronary heart disease (CHD) risk. On the basis of epidemiological studies that demonstrated mainly positive effects of postmenopausal hormone therapy on CHD as well as on risk markers of CHD, it has been suggested that CHD could be prevented in postmenopausal women with long-term hormone therapy. However, since the publications of the Heart and Estrogen/progestin Replacement Study and the Women's Health Initiative trial, prescription of hormone therapy for the prevention of CHD has become controversial. Major efforts have been made to identify alternatives for hormone therapy. Compounds suggested have included selective estrogen receptor modulators (SERMs), which represent a class with a growing number of compounds that act as either estrogen receptor agonists or antagonists in a tissue-specific manner. This pharmacological profile may offer the opportunity to dissociate favourable estrogenic effects on the bone and cardiovascular system from unfavourable stimulatory effects on the breast and endometrium. Two SERMs presently on the market are tamoxifen and raloxifene. The only data available regarding the effects of tamoxifen on cardiovascular events in postmenopausal women are from breast cancer trials. These trials found fewer fatal myocardial events in women randomly assigned to tamoxifen compared with women assigned to placebo. Raloxifene is a second-generation SERM that has been shown to prevent osteoporotic fractures, is safe for the endometrium and holds high promise for the prevention of breast cancer. The effect of raloxifene on CHD is still uncertain. On the basis of the MORE (Multiple Outcomes of Raloxifene Evaluation) trial, raloxifene may offer some protection to women with CHD or to those who are at high risk of CHD. Proof that raloxifene reduces the risk of CHD requires a clinical trial with hard clinical endpoints. Such a study is currently underway. Next-generation SERMs taken into clinical development include idoxifene, droloxifene, ospemifene, arzoxifene, acolbifene/EM-800, levormeloxifene, lasofoxifene, bazedoxifene and HMR 3339. The aim is to find a compound with the ideal profile, that is, alleviation of climacteric symptoms and prevention of osteoporotic fractures, but without an adverse effect on the breast and endometrium, and no negative effect or even a beneficial effect on the cardiovascular system and the brain. Currently, limited data are available with regard to these next-generation SERMs and CHD. Nevertheless, some of these novel agents provide arguments for continuing the search for an ideal SERM.

Effect of postmenopausal hormone replacement therapy on cardiovascular performance

Postmenopausal hormone replacement therapy (HRT) has usually been evaluated the relationship with atherosclerotic disease, whereas its effect on direct cardiac functions hasn't been investigated in detail. This study was planned to investigate the long-term effects of HRT on cardiac functions and exercise performance.

METHODS

Thirty-six postmenopausal women (mean age: 51 +/- 4 years, 39-60 years) were prospectively analyzed with pulsed wave Doppler echocardiography and symptom-limited exercise stress test before HRT (oral 0.625 mg conjugated estrogen and 2.5 mg medroxyprogesteron acetate/day), and at the third and the sixth months. The effect of HRT on left ventricular ejection fraction (EF), early filling velocity (E wave) and late filling velocity (A wave), E wave deceleration time (EDT), E/A ratio, myocardial performance index (MPI), exercise duration and METS changes were examined.

RESULTS

HRT did not significantly alter the left ventricular EF. At the third month of HRT, there was an insignificant increase in E wave, EDT, and E/A ratio, whereas an insignificant decrease was noted in MPI (P > 0.05). However, at the sixth month of HRT, these changes became significant (68 +/- 12 vs. 75 +/- 13 cm/s, P < 0.01; 171 +/- 24 vs. 184 +/- 14 ms, P < 0.01; 1.01 +/- 0.23 vs. 1.11 +/- 0.27, P < 0.01, and 44 +/- 9 vs. 39 +/- 8%, P < 0.001, respectively). On the other hand, exercise duration and exercise METS values showed significant improvements at the third month of HRT (423 +/- 104 vs. 482 +/- 104 s, P < 0.001; 8.2 +/- 1.7 vs. 9.1 +/- 2 METS, P < 0.001). These improvements also continued at the sixth month of HRT. In conclusion, postmenopausal HRT leads to a progressive improvement on left ventricular function parameters, and in parallel, in exercise performance.

Effects of oral and transdermal low-dose estrogen therapy on echocardiographic parameters of cardiac function

OBJECTIVE

To investigate the effects of transdermal 17 beta-estradiol (E(2)) compared with oral unopposed as well as opposed E(2) on echocardiographic parameters of left ventricular (LV) systolic and diastolic function.

DESIGN

A prospective, randomized, double-blind, placebo-controlled, multi-center study.

SETTING

Gynecologic and cardiologic outpatient departments.

PATIENT(S)

One hundred fifty-two healthy hysterectomized postmenopausal women.

INTERVENTION(S)

Participants received daily placebo (n = 49) or transdermal E(2) (50 microg; tE(2) group, n = 33), or oral E(2) (1 mg; oE(2) group, n = 37), or oral E(2) (1 mg) combined with gestodene (25 microg; oE(2)+G group, n = 33) for thirteen 28-day treatment cycles.

MAIN OUTCOME MEASURE(S)

M-mode, quantitative two-dimensional, and Doppler echocardiographic measurements were performed at baseline and after 1 year.

RESULT(S)

Compared with placebo, tE(2) and oE(2) showed no statistically significant changes in LV function. oE(2)+G resulted in a statistically significant favorable increase in peak flow velocity, flow velocity integral, and mean acceleration. Furthermore, a favorable decrease was observed in interventricular septum thickness and ejection time.

CONCLUSION(S)

After 1 year of unopposed E(2), LV function remained unchanged. The oE(2)+G treatment showed a potential beneficial influence on LV systolic function.

Effect of hormone replacement therapy on cardiovascular disease: current opinion

Cardiovascular disease (CVD) is increasingly being recognised as having a profound effect on women, especially after menopause. Lack of oestrogen has been targeted as one of the reasons for increased incidence of CVD in postmenopausal women. Oestrogen has been found to have favourable effects on lipid profile, tone of vascular smooth muscle cells and fibrinogen levels. Several observational studies have supported these experimental findings, consistently demonstrating reduced cardiovascular risks in users of hormone replacement therapy (HRT). However, evidence from recent clinical trials has challenged this widespread belief. Heart and Estrogen/Progesterone Replacement Study II, Estrogen Replacement and Atherosclerosis trial and more recently, Women's Health Initiative, have shown that HRT has no role in primary and secondary prevention of CVD and most authorities currently do not advocate HRT for the prevention of CVD.

Effects of menopause on intraindividual changes in serum lipids, blood pressure, and body weight--the Chin-Shan Community Cardiovascular Cohort study

In Taiwan, the Chin-Shan Community Cardiovascular Cohort (CCCC) was assessed prospectively to determine whether the changes in cardiovascular risk factors for women age 45--54 years are due to menopause. The average paired percentage changes that occurred between baseline (1990-1991) and follow-up (4 years later) in fasting serum lipids were compared in three groups of women including groups of 59 and 224 who were pre- and postmenopausal, respectively, and a group of 118 who had spontaneously stopped menstruating. Postmenopausal women had the least gain in body mass index (BMI), whereas, mainly premenopausal women had increased systolic blood pressure (P<0.05). All women had elevated total cholesterol (TC) levels, with the greatest elevation in women transitioning into menopause (P<0.001). Low-density lipoprotein cholesterol (LDL-C) levels increased before and during the transition to menopause, but decreased after menopause (P<0.01). Age had significant association with changes in TC, triglyceride (TG) and LDL-C levels, whereas BMI had significant association with changes in TG, LDL-C, and high-density lipoprotein cholesterol (HDL-C) levels (P<0.05). After controlling for age and BMI, only differences in TC remained significant, with the greatest gain in women who stopped menstruating (12.9%) followed by pre- (6.5%) and postmenopausal women (4.8%). Changes in both systolic and diastolic blood pressures, and TG and HDL-C levels were not significantly different, but HDL-C levels declined between 11.5 and 14.7% in all groups. This study suggests an unfavorable effect of menopause on lipid metabolism, especially on the TC level, which was predominantly elevated during the transition to menopause. The decline of HDL-C is of concern.

Neither long-term treatment with raloxifene nor hormone replacement therapy modulate cardiac function in healthy postmenopausal women: two randomized, placebo-controlled, 2-year studies

OBJECTIVE

Our purpose was to investigate the long-term effects of raloxifene, compared with opposed and unopposed estrogen replacement therapy, on echocardiographic parameters of left ventricular systolic function in healthy postmenopausal women. A total of 157 women were studied in 2 randomized, double-blind, placebo-controlled, 2-year studies.

STUDY DESIGN

In study I, 60 postmenopausal women who had undergone hysterectomy received daily raloxifene, 60 mg (n = 15); raloxifene, 150 mg (n = 15); conjugated equine estrogens (CEE), 0.625 mg (n = 15); or placebo (n = 15). In study II, 97 postmenopausal women who had not undergone hysterectomy received daily raloxifene, 60 mg (n = 24); raloxifene, 150 mg (n = 24); CEE, 0.625 mg, plus medroxyprogesterone acetate (MPA), 2.5 mg (n = 24); or placebo (n = 25). M-mode, quantitative 2-dimensional and Doppler echocardiographic measurements were performed at baseline and after 1 and 2 years.

RESULTS

Neither after 1 year nor after 2 years of treatment were echocardiographic parameters found to differ from baseline in both raloxifene groups, as well as in the unopposed CEE and the CEE/MPA groups, compared with the placebo group.

CONCLUSION

Within 2 years of raloxifene treatment, no effect on echocardiographic parameters of left ventricular systolic function was found. Unopposed CEE or CEE/MPA also showed no effect.

[Hormone replacement therapy in ischemic heart disease prevention in women. Arguments in favor]

Numerous evidence have suggested a physiologic action of sexual steroids upon the cardiovascular system and the coherence of epidemiological studies have raised the possibility of a positive action of estradiol in preventing cardiovascular disease, specially through atheroma inhibition and other vascular wall-related mechanisms. From an experimental point of view, some clinical trials have demonstrated an improvement in some intermediate clinical variables, such as hypercholesterolemia and hypertension, after the administration of estradiol. Nonetheless, the HERS study, the first secondary prevention trial of estrogen and cardiovascular disease, failed to demonstrate these positive actions suggested by epidemiological studies and the efficacy of estradiol in the treatment of postmenopausal women with cardiovascular disease has been questioned. In spite of this, the HERS study has also been questioned because of different pitfalls in its development and, for some authors, it is inconclusive. Therefore, at present, it is not possible to make an evidence based clinical decision regarding the key question about the real actions of estradiol in the prevention of cardiovascular disease in postmenopausal women.

The effects of transdermal estradiol on the response to mental stress in postmenopausal women: a randomized trial

PURPOSE

Estrogens inhibit adrenomedullary catecholamine release and catecholamine-mediated responses to stress. We examined whether estrogen supplementation reduces the sympathoadrenal response to mental stress in postmenopausal women.

MATERIALS AND METHODS

We compared the effects of 3-week treatment with transdermal 17-beta-estradiol and placebo in 10 postmenopausal women using a randomized, blinded, crossover design. We measured plasma catecholamine levels and the cardiovascular and metabolic responses to a 15-minute stress with mental arithmetic. Treatments were compared using repeated measures analysis of variance.

RESULTS

During placebo treatment, mean (+/- SD) epinephrine levels reached a peak of 431 +/- 135 pmol/liter after 15 minutes of stress; the epinephrine response was blunted during estradiol treatment, with a peak of 357 +/- 77 pmol/liter (P <0.05). Estradiol also blunted the diastolic blood pressure response to stress (baseline levels of 78 +/- 15 mm Hg vs peak of 90 +/- 6 mm Hg during placebo; baseline of 80 +/- 8 mm Hg vs peak of 84 +/- 6 mm Hg during estradiol; P <0.05). Estradiol treatment also blunted the decrease in the standard deviation of the mean of the electrocardiographic RR intervals and the increase in the ratio between the low-frequency and high-frequency bandwidths.

CONCLUSION

We observed a moderate, although significant, reduction in markers of the stress response to mental arithmetic in postmenopausal women treated with transdermal 17-beta-estradiol.

Long-term estrogen replacement therapy is associated with improved exercise capacity in postmenopausal women without known coronary artery disease

BACKGROUND

Short-term estrogen administration improves vasodilation and has been shown to improve exercise capacity. However, it is unknown whether long-term estrogen replacement therapy is associated with improved exercise capacity in postmenopausal women without known coronary artery disease.

METHODS AND RESULTS

We studied 248 postmenopausal women without known coronary artery disease (mean age 63.5 years); 158 (64%) were current or past hormone replacement therapy (HRT) users and 108 (44%) were current users of HRT. Attributes potentially affecting exercise capacity and cardiac risk factors were carefully measured. These included duration of estrogen replacement therapy, all variables in the Framingham risk index, physical activity level, body mass index, waist-to-hip ratio, presence of osteoporosis, and family history of heart disease. We measured maximal oxygen uptake (MVO (2)) and anaerobic threshold as objective markers of exercise capacity. The relation between exercise capacity and use of HRT was analyzed with the use of logistic regression, controlling for confounding variables. We found that fitness, as measured by MVO (2) and anaerobic threshold, was significantly greater in women who had used HRT currently or in the past compared with women who had never used HRT. This difference in fitness was not confounded by age or physical activity level.

CONCLUSIONS

Estrogen replacement therapy is associated with increased exercise capacity as measured by MVO (2) and anaerobic threshold in postmenopausal women without coronary artery disease. This finding is consistent with the beneficial effect of short-term estrogen administration on improved endothelium-dependent and endothelium-independent vasodilation.

Effect of age on the exercise response in normal postmenopausal women during estrogen replacement therapy

Postmenopausal estrogen replacement therapy (ERT) has been associated with a reduced risk of coronary artery disease (CAD). Whether this apparent cardioprotective effect is mediated by a cardiovascular benefit during exercise, however, has not been clearly defined. To evaluate rest and exercise variables with and without ERT, a randomized crossover trial was conducted in 23 postmenopausal women, ranging in age from 44 to 75 years, mean age 57+/-8 years. The rest and exercise variables were compared on ERT and during a drug-free period. The baseline measure was compared to the effects after 4 weeks of ERT and after 4 drug-free weeks. Echocardiographic treadmill exercise variables of heart rate (HR), blood pressure, rate-pressure product (RPP), and cardiac dimensions were determined at baseline and at the end of each treatment period. In response to ERT, there was a decrease in low-density lipoprotein (LDL) cholesterol (drug-free: 142+/-40 mg/dl, ERT: 124+/-34 mg/dl) and an increase in high-density lipoprotein (HDL) cholesterol (drug-free: 52+/-14 mg/dl, ERT: 62+/-15 mg/dl, both p<0.01). At rest, the study population had no overall significant change in HR, blood pressure, RPP, or left ventricular end-systolic and end-diastolic diameters when ERT was compared to the drug-free period. However, subjects with the fastest baseline resting HR had the greatest decrease in HR with ERT relative to the drug-free period (p<0.05). During exercise, ERT effected no change in peak HR, blood pressure, or RPP, although end-systolic diameter decreased slightly (p<0.05). With ERT, subject age correlated negatively with systolic blood pressure (p<0.05) and RPP (p<0.01); both blood pressure and RPP decreased in older subjects. In conclusion, ERT has differential effects dependent on baseline HR and age.