Mechanisms of Elevated Cutaneous Vascular Tone in College-Aged Black Individuals.

Background: Hypertension prevalence is greatest in the US non-Hispanic Black population, possibly through reduced vascular function. Although heightened cutaneous vascular tone and vasoconstrictor responsiveness have been reported in Black individuals, the underlying physiological mechanisms remain unknown.

Methods: Thirteen Black (6 women, 22±2 years) and 10 non-Hispanic White (4 women, 25±4 years) participants underwent intradermal perfusion of norepinephrine alone (10 to 10 M; control) or coinfused with ascorbic acid (general antioxidant), L-NAME (-nitro- L-arginine methyl ester; a nitric oxide synthase inhibitor), or combined ascorbic acid and l-NAME.

Ageing attenuates regional vasoconstriction during acute lowering of upper and lower limbs.

The venoarteriolar and myogenic response (VMR) is a non-adrenergic, non-baroreflex-mediated mechanism that increases local vascular resistance and contributes to blood pressure (BP) regulation during orthostasis. Despite the importance of the VMR in human cardiovascular control, no information exists elucidating possible differences in the VMR with ageing and sex. We studied 26 healthy young adults [9 male; mean (SD) 28 (4) years old] and 18 healthy older adults [7 male; 71 (3) years old] during acute arm and leg dependency (i.

Blunted baroreflex-mediated sympathoinhibition and vasodilation to countdown before exercise in young women compared to men.

Purpose: In our previous study (Manabe et al., J Appl Physiol 128:1196-1206, 1985), we demonstrated that the cerebral and cardiovascular responses induced by a pre-exercise countdown elicited peripheral vasodilation via baroreflex-mediated sympathetic withdrawal, which is likely advantageous for rapid oxygen delivery to contracting skeletal muscles in young men. Whether this is also true in young women, who generally show different neuro-cardiovascular responses to stress compared to men, remains unknown.

Autonomic control of blood pressure in women: The roles of hypertension and aging.

Hypertension remains a leading cause of cardiovascular morbidity and mortality worldwide, with implications in women's health across the lifespan. Of note, autonomic nervous system imbalances have been linked to the development of hypertension and are present with natural aging and various conditions unique to women (e.g.

Cardiovascular and sympathetic neural responses during acute vagus nerve stimulation and subsequent static handgrip exercise in healthy adults.

Purpose: This study aimed to investigate cardiovascular and sympathetic neural responses during acute cervical non-invasive vagus nerve stimulation (nVNS) and subsequent static handgrip (SHG) exercise with post-exercise circulatory occlusion (PECO) in healthy humans.

Methods: Ten healthy adults (5 men and 5 women, 33 ± 9 [standard deviation] yrs) participated in this double-blinded, randomized, crossover study. Each participant was studied twice on two separate days, with approximately 4 weeks apart: once during the actual cervical nVNS and once during sham stimulation for 4 min each.

Maintained sympathetic reactivity but blunted pressor response to static handgrip exercise in heart failure with preserved ejection fraction.

Purpose: Recent studies have reported blunted increases in blood pressure (BP) during static handgrip (SHG) in patients with heart failure with preserved ejection fraction (HFpEF), which may be attributed to abnormal sympathetic reactivity during exercise and/or impaired muscle metaboreflex function. However, it is unknown whether the sympathetic neural response to SHG and isolated muscle metaboreflex activation via post-exercise circulatory occlusion (PECO) are attenuated in HFpEF.

Methods: Thirty-nine patients with HFpEF and 24 age-matched non-HFpEF controls were studied in the supine position.

Sympathetic Neural Control at Rest and During the Cold Pressor Test in Patients With Heart Failure With Preserved Ejection Fraction.

Background: We tested the hypothesis that patients with heart failure with preserved ejection fraction (HFpEF) would have greater muscle sympathetic nerve activity (MSNA) at rest and sympathetic reactivity during a cold pressor test compared with non-heart failure controls. Further, given the importance of the baroreflex modulation of MSNA in the control of blood pressure (BP), we hypothesized that patients with HFpEF would exhibit a reduced sympathetic baroreflex sensitivity.

Methods: Twenty-eight patients with HFpEF and 44 matched controls (mean±SD: 71±8 versus 70±7 years; 9 men/19 women versus 16 men/28 women) were studied.

Sympathetic and hemodynamic responses to exercise in heart failure with preserved ejection fraction.

Excessive sympathetic activity during exercise causes heightened peripheral vasoconstriction, which can reduce oxygen delivery to active muscles, resulting in exercise intolerance. Although both patients suffering from heart failure with preserved and reduced ejection fraction (HFpEF and HFrEF, respectively) exhibit reduced exercise capacity, accumulating evidence suggests that the underlying pathophysiology may be different between these two conditions. Unlike HFrEF, which is characterized by cardiac dysfunction with lower peak oxygen uptake, exercise intolerance in HFpEF appears to be predominantly attributed to peripheral limitations involving inadequate vasoconstriction rather than cardiac limitations.

Effects of posture changes on dynamic cerebral autoregulation during early pregnancy in women with obesity and/or sleep apnea.

The incidence of syncope during orthostasis increases in early human pregnancy, which may be associated with cerebral blood flow (CBF) dysregulation in the upright posture. In addition, obesity and/or sleep apnea per se may influence CBF regulation due to their detrimental impacts on cerebrovascular function. However, it is unknown whether early pregnant women with obesity and/or sleep apnea could have impaired CBF regulation in the supine position and whether this impairment would be further exacerbated in the upright posture.

The acute effect of whole-body heat therapy on peripheral and cerebral vascular reactivity in Black and White females.

Among females in the U.S., Black females suffer the most from cardiovascular disease and stroke.

Differential regulation of sympathetic neural burst frequency and amplitude throughout normal pregnancy: a longitudinal study.

Sympathetic activation is a hallmark of pregnancy. However, longitudinal assessments of muscle sympathetic nerve activity (MSNA) in pregnancy are scarce and have primarily focused on burst occurrence (frequency) at rest, despite burst strength (amplitude) representing distinct characteristics of sympathetic outflow. Thus, we assessed MSNA burst amplitude distributions in healthy women to determine the impact of normal pregnancy on neural discharge patterns in response to orthostatic stress.

Exercise Leg Blood Flow Is Preserved in Long-term Breast Cancer Survivors Previously Treated With Anthracycline Chemotherapy.

Purpose: The objective of this investigation was to compare the acute hemodynamic responses during single-leg knee extension (SLKE) exercise between female breast cancer (BC) survivors previously treated with anthracycline chemotherapy and age- and sex-matched control (CON) subjects.

Methods: Fourteen BC survivors (age: 61 ± 7 yr; time post-anthracycline therapy: 12 ± 6 yr) and nine CON subjects (age: 59 ± 7 yr) performed SLKE exercise at 25%, 50%, and 75% of peak power output during which heart rate, blood pressure (BP), leg blood flow (Doppler ultrasonography), and vascular conductance (leg blood flow/mean BP) were measured. Quadriceps mass was estimated from thigh volume and skinfold measures.

The impact of a plant-based diet on indices of cardiovascular health in African Americans: a cross-sectional study.

African-American (AA) individuals are disproportionately affected by cardiovascular diseases. Plant-based diets (PBD) may be cardioprotective in part through their high antioxidant capacity and low inflammatory load. We tested the hypothesis that AA individuals adhering to a 100% PBD would have better vascular health than AA individuals following a typical American diet (TAD).

Contributions of endothelin-1 and l-arginine to blunted cutaneous microvascular function in young, black women.

Non-Hispanic black (BL) individuals have the greatest prevalence of cardiovascular disease (CVD), relative to other racial/ethnic groups (e.g., non-Hispanic white population; WH), which may be secondary to blunted vascular function.

GLOBAL REACH 2018: intra-arterial vitamin C improves endothelial-dependent vasodilatory function in humans at high altitude.

High altitude-induced hypoxaemia is often associated with peripheral vascular dysfunction. However, the basic mechanism(s) underlying high-altitude vascular impairments remains unclear. This study tested the hypothesis that oxidative stress contributes to the impairments in endothelial function during early acclimatization to high altitude.

Cerebrovascular reactivity is blunted in young adults with major depressive disorder: The influence of current depressive symptomology.

Background: In middle-aged adults with depression, cerebral vasodilatory reactivity is blunted; however, this has not been examined in treatment-naïve young adults with major depressive disorder (MDD). We tested the hypothesis that cerebrovascular reactivity would be blunted in young adults (18-30 yrs) with MDD compared to healthy non-depressed adults (HA) and would be attenuated to a greater extent in adults with symptomatic MDD (sMDD) compared to adults with MDD in remission (euthymic MDD; eMDD).

Methods: Sixteen adults with MDD [21±3yrs; n = 8 sMDD (6 women); n = 8 eMDD (5 women)] and 14 HA (22±3yrs; 9 women) participated.

Global Research Expedition on Altitude-related Chronic Health 2018 Iron Infusion at High Altitude Reduces Hypoxic Pulmonary Vasoconstriction Equally in Both Lowlanders and Healthy Andean Highlanders.

Background: Increasing iron bioavailability attenuates hypoxic pulmonary vasoconstriction in both lowlanders and Sherpas at high altitude. In contrast, the pulmonary vasculature of Andean individuals with chronic mountain sickness (CMS) is resistant to iron administration. Although pulmonary vascular remodeling and hypertension are characteristic features of CMS, the effect of iron administration in healthy Andean individuals, to our knowledge, has not been investigated.

Impact of cutaneous blood flow on NIR-DCS measures of skeletal muscle blood flow index.

Near-infrared diffuse correlation spectroscopy (NIR-DCS) is an optical technique for estimating relative changes in skeletal muscle perfusion during exercise but may be affected by changes in cutaneous blood flow, as photons emitted by the laser must first pass through the skin. Accordingly, the purpose of this investigation was to examine how increased cutaneous blood flow affects NIR-DCS blood flow index (BFI) at rest and during exercise using a passive whole body heating protocol that increases cutaneous, but not skeletal muscle, perfusion in the uncovered limb. BFI and cutaneous perfusion (laser-Doppler flowmetry) were assessed in 15 healthy young subjects before (e.

Global Reach 2018: Nitric oxide-mediated cutaneous vasodilation is reduced in chronic, but not acute, hypoxia independently of enzymatic superoxide formation.

We tested the hypotheses that 1) cutaneous microvascular function is impaired by acute normobaric and chronic hypobaric hypoxia and 2) that the superoxide free radical (via NADPH oxidase or xanthine oxidase) contributes to this impairment via nitric oxide (NO) scavenging. Local heating-induced cutaneous hyperemia (39 °C) was measured in the forearm of 11 male lowlanders at sea level (SL) and following 14-18 days at high altitude (HA; 4340 m in Cerro de Pasco, Peru), and compared to 11 highlanders residing permanently at this elevation. Cutaneous vascular conductance (CVC; laser-Doppler flux/mean arterial pressure) was not different during 39 °C [control site: 73 (19) vs.

Differences in joint power distribution in high and low lactate threshold cyclists.

Purpose: The biomechanical differences between cyclists with a high compared with a low blood lactate threshold (HLT; 80% VO vs LLT, 70% VO) have yet to be completely described. We hypothesize that HLT cyclists reduce the stress placed on the knee extensor muscles by increasing the relative contribution from the hip joint during high-intensity cycling.

Method: Sixteen well-trained endurance athletes, with equally high VO while cycling and running completed submaximal tests during incremental exercise to identify lactate threshold ([Formula: see text]) while running and cycling.