Regional cerebral perfusion and sympathetic activation during exercise in hypoxia and hypercapnia: preliminary insight into 'Cushing's mechanism'.

We examined the interactive influence of hypoxia and exercise, and hypercapnia and exercise, on regional cerebral perfusion and sympathetic activation. Twenty healthy young adults (seven women) completed study trials including (1) rest in normoxia ( : ∼96%, : ∼36 mmHg), normocapnic hypoxia ( : ∼84%, : ∼36 mmHg), and normoxic hypercapnia ( : ∼98%, : ∼46 mmHg) and (2) unilateral rhythmic handgrip exercise (45% of maximal voluntary contraction at 1 Hz for 3 min) under the same gas conditions. Based on the exercising arm, blood flow in the contralateral internal carotid (ICA) and ipsilateral vertebral (VA) arteries, anterior and posterior cerebral O delivery ( ), and muscle sympathetic nerve activity (MSNA) were measured in each trial.

Preserved endothelium-independent vascular function with aging in men and women: evidence from the peripheral and cerebral vasculature.

In the peripheral and cerebral vasculature, the impact of aging and sex on the endothelial-independent functional capacity of vascular smooth muscle cells (VSMCs) is not well understood, nor is it known whether such VSMC functions in these vascular beds reflect one another. Therefore, endothelium-independent dilation, at both the conduit (Δ diameter) and microvascular (Δ vascular conductance, VC) level, elicited by sublingual nitroglycerin (NTG, 0.8 mg of Nitrostat), compared with sham-delivery (control), was assessed using Doppler ultrasound in the popliteal (PA) and middle cerebral (MCA) artery of 20 young [23 ± 4 yr, 10 males (YM)/10 females (YF)] and 21 old [69 ± 5 yr, 11 males (OM)/10 females (OF)] relatively healthy adults.

Pharmacological modulation of adrenergic tone alters the vasodilatory response to passive leg movement in young but not in old adults.

The age-related increase in α-adrenergic tone may contribute to decreased leg vascular conductance (LVC) both at rest and during exercise in the old. However, the effect on passive leg movement (PLM)-induced LVC, a measure of vascular function, which is markedly attenuated in this population, is unknown. Thus, in eight young (25 ± 5 yr) and seven old (65 ± 7 yr) subjects, this investigation examined the impact of systemic β-adrenergic blockade (propanalol, PROP) alone, and PROP combined with either α-adrenergic stimulation (phenylephrine, PE) or α-adrenergic inhibition (phentolamine, PHEN), on PLM-induced vasodilation.

Postexercise Hypotension Is Delayed in Men With Obesity and Hypertension.

Background: Postexercise hypotension (PEH) can play a major role in the daily blood pressure management among individuals with hypertension. However, there are limited data on PEH in persons with obesity and hypertension, and no PEH data in this population beyond 90 min postexercise.

Purpose: The purpose of this study was to determine if PEH could be elicited in men with obesity and hypertension during a 4-h postexercise measurement period.

Reliability of the passive leg movement assessment of vascular function in men.

New Findings: What is the central question of this study? Use of the passive leg movement (PLM) test, a non-invasive assessment of microvascular function, is on the rise. However, PLM reliability in men has not been adequately investigated, nor has such reliability data, in men, been compared to the most commonly employed vascular function assessment, flow-mediated vasodilation (FMD). What is the main finding and its importance? PLM is a reliable method to assess vascular function in men, and is comparable to values previously reported for PLM in women, and for FMD.

Effects of indulgent food snacking, with and without exercise training, on body weight, fat mass, and cardiometabolic risk markers in overweight and obese men.

We hypothesized that exercise training would prevent gains in body weight and body fat, and worsening of cardiometabolic risk markers, during a 4-week period of indulgent food snacking in overweight/obese men. Twenty-eight physically inactive men (ages 19-47 yr) with body mass index (BMI) ≥25 kg/m consumed 48 donuts (2/day, 6 days/week; ~14,500 kcal total) for 4 weeks while maintaining habitual diet. Men were randomly assigned to control (n = 9), moderate-intensity continuous training (MICT; n = 9), or high-intensity interval training (HIIT; n = 10).

The passive leg movement technique for assessing vascular function: the impact of baseline blood flow.

New Findings: What is the central question of this study? The passive leg movement (PLM) assessment of vascular function utilizes the blood flow response in the common femoral artery (CFA): what is the impact of baseline CFA blood flow on the PLM response? What is the main finding and its importance? Although an attenuated PLM response is not an obligatory consequence of increased baseline CFA blood flow, increased blood flow through the deep femoral artery will diminish the response. Care should be taken to ensure that a genuine baseline leg blood flow is obtained prior to performing a PLM vascular function assessment.

Abstract: The passive leg movement (PLM) assessment of vascular function utilizes the blood flow response in the common femoral artery (CFA).

The dynamic adjustment of mean arterial pressure during exercise: a potential tool for discerning cardiovascular health status.

The regulation of mean arterial pressure (MAP) during exercise has important physiological and clinical implications. Kinetics analysis on numerous physiological variables following the transition from unloaded-to-loaded exercise has revealed important information regarding their control. Surprisingly, the dynamic response of MAP during this transition remains to be quantified.

Vascular function in continuous-flow left ventricular assist device recipients: effect of a single pulsatility treatment session.

Vascular function is further attenuated in patients with chronic heart failure implanted with a continuous-flow left ventricular assist device (LVAD), likely due to decreased arterial pulsatility, and this may contribute to LVAD-associated cardiovascular complications. However, the impact of increasing pulsatility on vascular function in this population is unknown. Therefore, 15 LVAD recipients and 15 well-matched controls underwent a 45-min, unilateral, arm pulsatility treatment, evoked by intermittent cuff inflation/deflation (2-s duty cycle), distal to the elbow.

Sacubitril-valsartan improves conduit vessel function and functional capacity and reduces inflammation in heart failure with reduced ejection fraction.

The Prospective comparison of ARNI with angiotensin-converting enzyme inhibitor to Determine Impact on Global Mortality and morbidity in Heart Failure trial identified a marked reduction in the risk of death and hospitalization for heart failure in patients with heart failure with reduced ejection fraction (HFrEF) treated with sacubitril-valsartan (trade name Entresto), but the physiological processes underpinning these improvements are unclear. We tested the hypothesis that treatment with sacubitril-valsartan improves peripheral vascular function, functional capacity, and inflammation in patients with HFrEF. We prospectively studied patients with HFrEF ( = 11, 10 M/1 F, left ventricular ejection fraction = 27 ± 8%) on optimal, guideline-directed medical treatment who were subsequently prescribed sacubitril-valsartan (open-label, uncontrolled, and unblinded).

Chronic antioxidant administration restores macrovascular function in patients with heart failure with reduced ejection fraction.

New Findings: What is the central question of this study? We aimed to examine oxidative stress, antioxidant capacity and macro- and microvascular function in response to 30 days of oral antioxidant administration in patients with heart failure with reduced ejection fraction. What is the main finding and its importance? We observed an approximately twofold improvement in macrovascular function, assessed via brachial artery flow-mediated dilatation, and a reduction in oxidative stress after antioxidant administration in patients with heart failure with reduced ejection fraction. The improvement in macrovascular function was reversed 1 week after treatment cessation.

Imaging transcranial Doppler ultrasound to measure middle cerebral artery blood flow: the importance of measuring vessel diameter.

Cerebral blood flow (CBF) is commonly inferred from blood velocity measurements in the middle cerebral artery (MCA), using nonimaging, transcranial Doppler ultrasound (TCD). However, both blood velocity and vessel diameter are critical components required to accurately determine blood flow, and there is mounting evidence that the MCA is vasoactive. Therefore, the aim of this study was to employ imaging TCD (ITCD), utilizing color flow images and pulse wave velocity, as a novel approach to measure both MCA diameter and blood velocity to accurately quantify changes in MCA blood flow.

Strong Relationship Between Vascular Function in the Coronary and Brachial Arteries.

Early detection of coronary artery dysfunction is of paramount cardiovascular clinical importance, but a noninvasive assessment is lacking. Indeed, the brachial artery flow-mediated dilation test only weakly correlated with acetylcholine-induced coronary artery function ( r=0.36).

High-intensity interval exercise attenuates but does not eliminate endothelial dysfunction after a fast food meal.

We investigated whether two different bouts of high-intensity interval exercise (HIIE) could attenuate postprandial endothelial dysfunction. Thirteen young (27 ± 1 yr), nonexercise-trained men underwent three randomized conditions: 1) four 4-min intervals at 85-95% of maximum heart rate separated by 3 min of active recovery (HIIE 4 × 4), 2) 16 1-min intervals at 85-95% of maximum heart rate separated by 1 min of active recovery (HIIE 16 × 1), and 3) sedentary control. HIIE was performed in the afternoon, ~18 h before the morning fast food meal (1,250 kcal, 63g of fat).

Adaptive goal setting and financial incentives: a 2 × 2 factorial randomized controlled trial to increase adults' physical activity.

Background: Emerging interventions that rely on and harness variability in behavior to adapt to individual performance over time may outperform interventions that prescribe static goals (e.g., 10,000 steps/day).

High glucose impairs acetylcholine-mediated vasodilation in isolated arteries from Mourning doves (Z. macroura).

Normal avian plasma glucose levels are 1.5-2 times greater than mammals of similar size. In mammals, hyperglycemia induces oxidative stress and impaired endothelium-dependent vasodilation.

The Walking Interventions Through Texting (WalkIT) Trial: Rationale, Design, and Protocol for a Factorial Randomized Controlled Trial of Adaptive Interventions for Overweight and Obese, Inactive Adults.

Background: Walking is a widely accepted and frequently targeted health promotion approach to increase physical activity (PA). Interventions to increase PA have produced only small improvements. Stronger and more potent behavioral intervention components are needed to increase time spent in PA, improve cardiometabolic risk markers, and optimize health.

Pathophysiological responses to a schistosome infection in a wild population of mourning doves (Zenaida macroura).

The blood trematode Gigantobilharzia huronensis typically infects passerine birds and has not been reported in other orders of wild birds. However, in the summer of 2011 in Tempe, Arizona, USA, mourning doves (Zenaida macroura; order: Columbiformes) were collected with infections of G. huronensis.

Fitness versus Fatness: Which Influences Health and Mortality Risk the Most?

Cardiorespiratory fitness (CRF) is a more powerful predictor of mortality than body mass index or adiposity, and improving CRF is more important than losing body fat for reducing risk of cardiovascular disease and all-cause mortality. Data on reduced morbidity and mortality associated with increased CRF are strong and consistent. By contrast, data on intentional weight loss and mortality are uncertain, and weight loss-induced risk factor modification may be largely transient.