Reflex sympathetic activation to inspiratory muscle loading is attenuated in females relative to males.

Intense inspiratory muscle work can evoke a metabolite-stimulated pressor reflex, commonly referred to as the respiratory muscle metaboreflex. When completing similar relative and absolute levels of inspiratory work, females have an attenuated blood pressure response. We sought to test the hypothesis that the lower blood pressure response to the respiratory muscle metaboreflex in females is associated with a reduced sympathetic response.

Physical activity before and during pregnancy and maternal mental health: A systematic review and meta-analysis of observational studies.

Objective: To examine the influence of physical activity before and during pregnancy on maternal mental health outcomes.

Methods: Ten electronic databases were searched up to May 11, 2021. Studies of all observational designs (except case studies and reviews) were included, which contained information on the relevant population (women before and or during pregnancy), exposures (objective or subjective measures of physical activity), comparator (low or no physical activity), and outcomes (diagnosis and symptom severity of depression or anxiety, quality of life scores, stress and emotions).

Short-term hypoxia does not promote arrhythmia during voluntary apnea.

The presence of bradycardic arrhythmias during volitional apnea at altitude may be caused by chemoreflex activation/sensitization. We investigated whether bradyarrhythmic episodes became prevalent in apnea following short-term hypoxia exposure. Electrocardiograms (ECG; lead II) were collected from 22 low-altitude residents (F = 12; age=25 ± 5 years) at 671 m.

Highs and lows of sympathetic neurocardiovascular transduction: influence of altitude acclimatization and adaptation.

High-altitude (>2,500 m) exposure results in increased muscle sympathetic nervous activity (MSNA) in acclimatizing lowlanders. However, little is known about how altitude affects MSNA in indigenous high-altitude populations. Additionally, the relationship between MSNA and blood pressure regulation (i.

Sympathetic nervous system activity and reactivity in women with gestational diabetes mellitus.

Introduction: Gestational diabetes mellitus (GDM) is associated with vascular dysfunction. Sympathetic nervous system activity (SNA) is an important regulator of vascular function, and is influenced by glucose and insulin. The association between GDM and SNA (re)activity is unknown.

Global REACH 2018: Andean highlanders, chronic mountain sickness and the integrative regulation of resting blood pressure.

New Findings: What is the central question of this study? Does chronic mountain sickness (CMS) alter sympathetic neural control and arterial baroreflex regulation of blood pressure in Andean (Quechua) highlanders? What is the main finding and its importance? Compared to healthy Andean highlanders, basal sympathetic vasomotor outflow is lower, baroreflex control of muscle sympathetic nerve activity is similar, supine heart rate is lower and cardiovagal baroreflex gain is greater in mild CMS. Taken together, these findings reflect flexibility in integrative regulation of blood pressure that may be important when blood viscosity and blood volume are elevated in CMS.

Abstract: The high-altitude maladaptation syndrome chronic mountain sickness (CMS) is characterized by excessive erythrocytosis and frequently accompanied by accentuated arterial hypoxaemia.

Global REACH: Assessment of Brady-Arrhythmias in Andeans and Lowlanders During Apnea at 4330 m.

Ascent to altitude increases the prevalence of arrhythmogenesis in low-altitude dwelling populations (Lowlanders). High altitude populations (i.e.

Muscle sympathetic reactivity to apneic and exercise stress in high-altitude Sherpa.

Lowland-dwelling populations exhibit persistent sympathetic hyperactivity at altitude that alters vascular function. High-altitude populations, such as Sherpa, have previously exhibited greater peripheral blood flow in response to acute stress than Lowlanders, which may be explained through lower sympathetic activity. Our purpose was to determine whether Sherpa exhibit lower sympathetic reactivity to stress than Lowlanders.

Physical Activity in Pregnancy Is Associated with Increased Flow-mediated Dilation.

Purpose: To determine the role of moderate-to-vigorous physical activity (MVPA) and sedentary behavior in flow-mediated dilation (FMD) and glucose metabolism during late pregnancy.

Methods: Seventy normotensive, euglycemic pregnant women (31.6 ± 2.

A review of acute responses, after-effects and chronic complications related to microneurography.

Microneurography, a technique used to detect postganglionic sympathetic nerve traffic in humans, is increasingly used to further the understanding of autonomic regulation in health and disease. The technique involves the transcutaneous insertion of a microelectrode into a peripheral nerve, following which, a variety of adverse acute responses; after-effect and chronic complications have been documented. Here, we comprehensively review the potential adverse outcomes of microneurography and provide updated quantifiable incidence rates of their occurrence within a general population.

Baroreflex control of sympathetic vasomotor activity and resting arterial pressure at high altitude: insight from Lowlanders and Sherpa.

Key Points: Hypoxia, a potent activator of the sympathetic nervous system, is known to increase muscle sympathetic nerve activity (MSNA) to the peripheral vasculature of native Lowlanders during sustained high altitude (HA) exposure. We show that the arterial baroreflex control of MSNA functions normally in healthy Lowlanders at HA, and that upward baroreflex resetting permits chronic activation of basal sympathetic vasomotor activity under this condition. The baroreflex MSNA operating point and resting sympathetic vasomotor outflow both are lower for highland Sherpa compared to acclimatizing Lowlanders; these lower levels may represent beneficial hypoxic adaptation in Sherpa.

Mechanisms of sympathetic regulation during Apnea.

Volitional Apnea produces a robust peak sympathetic response through several interacting mechanisms. However, the specific contribution of each mechanism has not been elucidated. Muscle sympathetic activity was collected in participants (n = 10; 24 ± 3 years) that performed four maximal volitional apneas aimed at isolating lung-stretch (mechanical) and chemoreflex drive: (Ainslie and Duffin ) end-expiratory breath-hold, (Ainslie et al.

Peripheral chemoreceptor deactivation attenuates the sympathetic response to glucose ingestion.

Acute increases in blood glucose are associated with heightened muscle sympathetic nerve activity (MSNA). Animal studies have implicated a role for peripheral chemoreceptors in this response, but this has not been examined in humans. Heart rate, cardiac output (CO), mean arterial pressure, total peripheral conductance, and blood glucose concentrations were collected in 11 participants.

Chemoreflex mediated arrhythmia during apnea at 5,050 m in low- but not high-altitude natives.

Peripheral chemoreflex mediated increases in both parasympathetic and sympathetic drive under chronic hypoxia may evoke bradyarrhythmias during apneic periods. We determined whether 1) voluntary apnea unmasks arrhythmia at low (344 m) and high (5,050 m) altitude, 2) high-altitude natives (Nepalese Sherpa) exhibit similar cardiovagal responses at altitude, and 3) bradyarrhythmias at altitude are partially chemoreflex mediated. Participants were grouped as Lowlanders ( n = 14; age = 27 ± 6 yr) and Nepalese Sherpa ( n = 8; age = 32 ± 11 yr).

Facilitating activation of the peroneus longus: electromyographic analysis of exercises consistent with biomechanical function.

Exercises for the ankle are often used to improve sport performance through balance and stability or to prevent or recover from ankle injury. Ankle training programs often include exercises for the primary muscle of the lateral ankle, the peroneus longus (PL). However, many exercises for the PL are non-weight bearing and unidirectional.