Impact of sympathetic nervous system activity on post-exercise flow-mediated dilatation in humans.

Transient reduction in vascular function following systemic large muscle group exercise has previously been reported in humans. The mechanisms responsible are currently unknown. We hypothesised that sympathetic nervous system activation, induced by cycle ergometer exercise, would contribute to post-exercise reductions in flow-mediated dilatation (FMD).

Impact of 2-Weeks Continuous Increase in Retrograde Shear Stress on Brachial Artery Vasomotor Function in Young and Older Men.

Background: Although acute elevation in retrograde shear rate (SR) impairs endothelial function, no previous study has explored the effect of prolonged elevation of retrograde SR on conduit artery vascular function. We examined the effect of 2-weeks elevation of retrograde SR on brachial artery endothelial function in young and in older men.

Methods And Results: Thirteen healthy young (23±2 years) and 13 older men (61±5 years) were instructed to continuously wear a compression sleeve around the right forearm to chronically (2 weeks) elevate brachial artery retrograde SR in 1 arm.

Opposing effects of shear-mediated dilation and myogenic constriction on artery diameter in response to handgrip exercise in humans.

While the impact of changes in blood flow and shear stress on artery function are well documented, the acute effects of increases in arterial pressure are less well described in humans. The aim of this study was to assess the effect of 30 min of elevated blood pressure, in the absence of changes in shear stress or sympathetic nervous system (SNS) activation, on conduit artery diameter. Ten healthy male subjects undertook three sessions of 30 min unilateral handgrip exercise at 5, 10, and 15% of maximal voluntary contractile (MVC) strength.

Arterial structure and function in vascular ageing: are you as old as your arteries?

Advancing age may be the most potent independent predictor of future cardiovascular events, a relationship that is not fully explained by time-related changes in traditional cardiovascular risk factors. Since some arteries exhibit differential susceptibility to atherosclerosis, generalisations regarding the impact of ageing in humans may be overly simplistic, whereas in vivo assessment of arterial function and health provide direct insight. Coronary and peripheral (conduit, resistance and skin) arteries demonstrate a gradual, age-related impairment in vascular function that is likely to be related to a reduction in endothelium-derived nitric oxide bioavailability and/or increased production of vasoconstrictors (e.

Within-subject Variation of Thermoregulatory Responses during Repeated Exercise Bouts.

Aim: To assess the within-subject variation of thermoregulatory responses during 2 consecutive 15-km road races. Secondly, we explored whether gastrointestinal temperature (TGI) data from the first race could improve our previously established predictive model for finish TGI in the second race.

Methods: We measured TGI before and immediately after both races in 58 participants and determined correlation coefficients.

Impact of retrograde shear rate on brachial and superficial femoral artery flow-mediated dilation in older subjects.

Unlabelled: An inverse, dose-dependent relationship between retrograde shear rate and brachial artery endothelial function exists in young subjects. This relationship has not been investigated in older adults, who have been related to lower endothelial function, higher resting retrograde shear rate and higher risk of cardiovascular disease.

Aim: To investigate the impact of a step-wise increase in retrograde shear stress on flow-mediated dilation in older males in the upper and lower limbs.

Impact of handgrip exercise intensity on brachial artery flow-mediated dilation.

Purpose: Previous studies that have examined the impact of exercise intensity on conduit artery endothelial function have involved large muscle group exercise which induces local and systemic effects. The aim of this study was to examine flow-mediated dilation (FMD) before and after incremental intensities of handgrip exercise (HE), to assess the role of local factors such as blood flow and shear rate on post-exercise brachial artery function.

Methods: Eleven healthy men attended the laboratory on three occasions.

Altered core and skin temperature responses to endurance exercise in heart failure patients and healthy controls.

Background: Exercise training represents a central aspect of rehabilitation of heart failure patients. Previous work on passive heating suggests impaired thermoregulatory responses in heart failure patients. However, no previous study directly examined thermoregulatory responses to an exercise bout, that is, active heating, as typically applied in rehabilitation settings in heart failure.

Impact of ischemic preconditioning on functional sympatholysis during handgrip exercise in humans.

Repeated bouts of ischemia followed by reperfusion, known as ischemic preconditioning (IPC), is found to improve exercise performance. As redistribution of blood from the inactive areas to active skeletal muscles during exercise (i.e.

Reproducibility of Cutaneous Vascular Conductance Responses to Slow Local Heating Assessed Using seven-Laser Array Probes.

Objective: Gradual local heating of the skin induces a largely NO-mediated vasodilatation. However, use of this assessment of microvascular health is limited because little is known about its reproducibility.

Methods: Healthy volunteers (n = 9) reported twice to the laboratory.

Heart failure patients demonstrate impaired changes in brachial artery blood flow and shear rate pattern during moderate-intensity cycle exercise.

What is the central question of this study? We explored whether heart failure (HF) patients demonstrate different exercise-induced brachial artery shear rate patterns compared with control subjects. What is the main finding and its importance? Moderate-intensity cycle exercise in HF patients is associated with an attenuated increase in brachial artery anterograde and mean shear rate and skin temperature. Differences between HF patients and control subjects cannot be explained fully by differences in workload.

Elevation in blood flow and shear rate prevents hyperglycemia-induced endothelial dysfunction in healthy subjects and those with type 2 diabetes.

Hyperglycemia, commonly present after a meal, causes transient impairment in endothelial function. We examined whether increases in blood flow (BF) protect against the hyperglycemia-mediated decrease in endothelial function in healthy subjects and patients with type 2 diabetes mellitus (T2DM). Ten healthy subjects and 10 age- and sex-matched patients with T2DM underwent simultaneous bilateral assessment of brachial artery endothelial function by means of flow-mediated dilation (FMD) using high-resolution echo-Doppler.

The impact of age on vascular smooth muscle function in humans.

Aim: Advanced age is associated with vascular endothelial dysfunction, characterized by reductions in the endothelium-dependent vasodilation of the conduit and resistance arteries, in part, from decreased nitric oxide bioavailability. Although vascular smooth muscle function (SMF), assessed by responsiveness to an exogenous nitric oxide donor, is typically reported to be intact, many of these studies are limited by a small sample size. Therefore, the purpose of this meta-analysis is to systematically review and determine whether vascular SMF is different between older versus young healthy individuals.

Interval exercise, but not endurance exercise, prevents endothelial ischemia-reperfusion injury in healthy subjects.

Endothelial ischemia-reperfusion (I/R) injury importantly contributes to the poor prognosis during ischemic (myocardial) events. Preconditioning, i.e.

Thermoregulation and fluid balance during a 30-km march in 60- versus 80-year-old subjects.

The presence of impaired thermoregulatory and fluid balance responses to exercise in older individuals is well established. To improve our understanding on thermoregulation and fluid balance during exercise in older individuals, we compared thermoregulatory and fluid balance responses between sexagenarians and octogenarians during prolonged exercise. Forty sexagenarians (60 ± 1 year) and 36 octogenarians (81 ± 2 year) volunteered to participate in a 30-km march at a self-selected pace.

Heart failure is associated with exaggerated endothelial ischaemia-reperfusion injury and attenuated effect of ischaemic preconditioning.

Background: Reperfusion is mandatory after ischaemia, but it also triggers ischaemia-reperfusion (IR)-injury. It is currently unknown whether heart failure alters the magnitude of IR-injury. Ischaemic preconditioning can limit IR-injury.

Distinct effects of blood flow and temperature on cutaneous microvascular adaptation.

Purpose: We performed two experiments to determine whether cutaneous microvascular adaptations in response to repeated core temperature (Tc) elevation are mediated by increases in skin blood flow (SkBF) and/or skin temperature.

Methods: Healthy subjects participated for 8 wk in thrice-weekly bouts of 30-min lower limb heating (40°C). In study 1, both forearms were "clamped" at basal skin temperature throughout each heating bout (n = 9).

Combined aerobic and resistance exercise training decreases peripheral but not central artery wall thickness in subjects with type 2 diabetes.

Objective: Little is known about the impact of exercise training on conduit artery wall thickness in type 2 diabetes. We examined the local and systemic impact of exercise training on superficial femoral (SFA), brachial (BA), and carotid artery (CA) wall thickness in type 2 diabetes patients and controls.

Methods: Twenty patients with type 2 diabetes and 10 age- and sex-matched controls performed an 8-week training study involving lower limb-based combined aerobic and resistance exercise training.

Time-course of vascular adaptations during 8 weeks of exercise training in subjects with type 2 diabetes and middle-aged controls.

Purpose: Exercise training in healthy volunteers rapidly improves vascular function, preceding structural remodelling. No study examined the time-course of such adaptations in subjects with a priori endothelial dysfunction.

Methods: We examined brachial artery endothelial and smooth muscle function using flow-mediated dilation (FMD) and glyceryl trinitrate (GTN) administration in 13 type 2 diabetes patients (59 ± 6 years) and 10 healthy subjects (58 ± 7 years) before, during (2-weekly) and after an 8-week training programme.

Impact of hypoxic versus normoxic training on physical fitness and vasculature in diabetes.

Background: Exercise training improves physical fitness, insulin resistance, and endothelial function in type 2 diabetes. Hypoxia may further optimize these beneficial effects. The aim of this study was to compare the effects of hypoxic versus normoxic exercise training on physical fitness, endothelial function, and insulin resistance in type 2 diabetes.

Association of Fitness Level With Cardiovascular Risk and Vascular Function in Older Nonexercising Individuals.

It is currently unknown whether differences in physical fitness in older, nonexercising individuals affect cardiovascular risk profile and vascular function. To examine this, 40 healthy older individuals (age 69 ± 4 years) who were classified as nonexercising for the past 5-10 years were allocated to a lower physical fitness (LF; VO2max 20.7 ± 2.

Randomized controlled trial using bosentan to enhance the impact of exercise training in subjects with type 2 diabetes mellitus.

In type 2 diabetes patients, endothelin (ET) receptor blockade may enhance blood flow responses to exercise training. The combination of exercise training and ET receptor blockade may represent a more potent stimulus than training alone to improve vascular function, physical fitness and glucose homeostasis. We assessed the effect of an 8 week exercise training programme combined with either ET blockade or placebo on vasculature, fitness and glucose homeostasis in people with type 2 diabetes.

Impact of eight weeks of repeated ischaemic preconditioning on brachial artery and cutaneous microcirculatory function in healthy males.

Background: Ischaemic preconditioning has well-established cardiac and vascular protective effects. Short interventions (one week) of daily ischaemic preconditioning episodes improve conduit and microcirculatory function. This study examined whether a longer (eight weeks) and less frequent (three per week) protocol of repeated ischaemic preconditioning improves vascular function.

The effect of black tea on blood pressure: a systematic review with meta-analysis of randomized controlled trials.

Objective: Epidemiological evidence has linked consumption of black tea, produced from Camellia sinensis, with a reduced risk of cardiovascular diseases. However, intervention studies on the effects of tea consumption on blood pressure (BP) have reported inconsistent results. Our objective was to conduct a systematic literature review with meta-analysis of controlled human intervention studies examining the effect of tea consumption on BP.