Retrograde and oscillatory shear increase across the menopause transition

Effects of the Follicular Menstrual Phase on Forearm Vascular Conductance in Abdominal Obese Premenopausal Women During Graded Handgrip Exercise

Purpose

Previous studies have reported a sympatholytic action of estrogen on the vasculature in response to increased sympathetic outflow, an effect most notable during exercise, providing for necessary increases in blood flow to working muscle. In contrast, elevated concentrations of progesterone can inhibit this action of estrogen, impairing increases in blood flow. We hypothesize that the peak concentration of estrogen during the proliferative portion of the follicular phase of the menstrual cycle in female humans will increase vascular conductance during exercise when the effects of progesterone are negligible. In addition, we hypothesize that overweight abdominally obese females will have an attenuated conductance response to dynamic exercise during the same menstrual phase.

Methods

Participants engaged in graded forearm exercise using an isotonic handgrip dynometer with sequential increases in resistance at a cadence of 30 contractions/minute until task failure. They performed exercise at time points of the menstrual cycle corresponding to low concentrations of both sex hormones and elevated estrogen, while progesterone remained low. Blood flow and vascular conductance were measured using Doppler ultrasound.

Results

This revealed a trend that abdominal obese women during a phase of low estrogen had a lower overall blood flow and vascular conductance response than healthy controls at matching resistance stages during rest and exercise. This group difference was attenuated during the proliferative phase with elevated circulating estrogen. There is not a statistically significant interaction between Ovarian Phase and Weight group (P = 0.778).

Conclusion

The results indicate that overweight women are at a disadvantage during exercise in increasing blood flow to working muscles, which can be detrimental to overall fitness improvement during the early and potentially late follicular phase of the menstrual cycle.

The effects of foot reflexology on depression during menopause: A randomized controlled clinical trial

OBJECTIVE

The purpose of this study was to determine the effects of foot reflexology on depression during menopause.

DESIGN

Randomized controlled clinical trial.

SETTING

Gynecology outpatient clinic.

INTERVENTIONS

We enrolled 90 menopausal women with depression. Participants were assigned to the intervention (n = 45) and control (n = 45) groups by block randomization. Participants in the intervention group received 15 min of foot reflexology on each foot for a total of 30 min in evenings, twice a week for six weeks. Participants in the control group received only the routine care for menopause patients.

MAIN OUTCOME MEASURES

The Beck Depression questionnaire was completed by all participants at the beginning of the trial and the end of the intervention and two months after completion of the intervention.

RESULTS

A total of 121 patients were assessed for eligibility to participate in the study. One-hundred patients met the criteria to participate, and 90 participants-45 participants in each group-completed the study. In the intervention group, the mean scores of depression before, immediately after, and two months after the study were 26.97 ± 4.47 (95% CI = 25.3-28.3), 22.55 ± 5.18 (95% CI = 20.9-24.1), and 21.20 ± 5.74 (95% CI = 19.4-22.9), respectively. In the control group, these scores were 26.15 ± 5.01 (95% CI = 24.6-27.6), 26.22 ± 5.14 (95% CI = 24.7-27.7), and 26.66 ± 3.87 (95%CI = 25.5-27.8), respectively. Using Repeated Measures ANOVA, the comparison of the mean scores of depression in the two groups indicated that the scores were decreased over time.

CONCLUSION

The findings indicated that the foot reflexology technique can be effective for reducing women's depression during menopause. However, considering the study's limitations, including a small sample size and no intervention in the control group, more studies are needed to verify the findings.

The impact of hypoxaemia on vascular function in lowlanders and high altitude indigenous populations

Exposure to hypoxia elicits widespread physiological responses that are critical for successful acclimatization; however, these responses may induce apparent maladaptive consequences. For example, recent studies conducted in both the laboratory and the field (e.g. at high altitude) have demonstrated that endothelial function is reduced in hypoxia. Herein, we review the several proposed mechanism(s) pertaining to the observed reduction in endothelial function in hypoxia including: (i) changes in blood flow patterns (i.e. shear stress), (ii) increased inflammation and production of reactive oxygen species (i.e. oxidative stress), (iii) heightened sympathetic nerve activity, and (iv) increased red blood cell concentration and mass leading to elevated nitric oxide scavenging. Although some of these mechanism(s) have been examined in lowlanders, less in known about endothelial function in indigenous populations that have chronically adapted to environmental hypoxia for millennia (e.g. the Peruvian, Tibetan and Ethiopian highlanders). There is some evidence indicating that healthy Tibetan and Peruvian (i.e. Andean) highlanders have preserved endothelial function at high altitude, but less is known about the Ethiopian highlanders. However, Andean highlanders suffering from chronic mountain sickness, which is characterized by an excessive production of red blood cells, have markedly reduced endothelial function. This review will provide a framework and mechanistic model for vascular endothelial adaptation to hypoxia in lowlanders and highlanders. Elucidating the pathways responsible for vascular adaption/maladaptation to hypoxia has potential clinical implications for disease featuring low oxygen delivery (e.g. heart failure, pulmonary disease). In addition, a greater understanding of vascular function at high altitude will clinically benefit the global estimated 85 million high altitude residents.

Aging women and their endothelium: probing the relative role of estrogen on vasodilator function

Despite significant decreases in cardiovascular disease (CVD) mortality in the past three decades, it still remains the leading cause of death in women. Following menopause and the accompanying loss of estrogen, women experience a unique, accelerated rise in CVD risk factors. Dysfunction of the endothelium represents an important antecedent to CVD development, with rapid declines in endothelial vasodilator function reportedly taking place across the menopause transition. Importantly, the decline in endothelial function is independent of chronological age and is associated with estrogen deficiency. Estrogen-mediated effects, including increasing nitric oxide bioavailability and attenuating oxidative stress and inflammation, contribute to preserving endothelial health. This review will discuss studies that have probed the role of estrogen on endothelial vasodilator function in women at discrete stages of the menopause transition and the effects of estradiol supplementation in postmenopausal women. Estrogen receptor signaling is also an important aspect of endothelial function in women, and studies suggest that expression is reduced with both acute and prolonged estrogen deficiency. Changes in regulatory mechanisms of estrogen receptor-α expression as well as sensitivity to estrogen may underlie the differential effects of estrogen therapy in early (≤5 yr past final menstrual period) and late postmenopausal women (>5 yr past final menstrual period). Lastly, this review presents potential therapeutic targets that include increasing l-arginine bioavailability and estrogen receptor activation to prevent endothelial dysfunction in postmenopausal women as a strategy for decreasing CVD mortality in this high-risk population.