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.

Speed Effects on the Accuracy of Heart Rate as Oxygen-Uptake Indicator in Short-Distance Shuttle Running.

Despite the accuracy of heart rate (HR) as an indicator of the aerobic engagement has been evaluated in several intermittent on-court activities, its validity as an oxygen uptake () indicator during shuttle running over short paths remains uncertain. Moreover, it is unclear whether speed may affect such validity. This study evaluated the HR ability in estimating the during 5-m shuttle running at different speeds.

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.

Long-Term Passive Leg Stretch Improves Systemic Vascular Responsiveness as Much as Single-Leg Exercise Training.

Purpose: The current study compared the local and systemic vascular responsiveness after small muscle mass endurance training or passive stretching training (PST).

Methods: Thirty-six sex-matched healthy participants underwent 8-wk single-leg knee extension (SLKE) (n = 12) training or PST (n = 12), or no intervention (control, n = 12). Before and after the intervention, local and systemic vascular responsiveness was assessed by Doppler ultrasound at the femoral (local effect) and brachial artery (systemic effect) during single passive leg movement and brachial flow-mediated dilation (FMD) test, respectively.

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 effects of 12 weeks of static stretch training on the functional, mechanical, and architectural characteristics of the triceps surae muscle-tendon complex.

Purpose: We investigated the effects of 12 weeks of passive static stretching training (PST) on force-generating capacity, passive stiffness, muscle architecture of plantarflexor muscles.

Methods: Thirty healthy adults participated in the study. Fifteen participants (STR, 6 women, 9 men) underwent 12-week plantarflexor muscles PST [(5 × 45 s-on/15 s-off) × 2exercises] × 5times/week (duration: 2250 s/week), while 15 participants (CTRL, 6 women, 9 men) served as control (no PST).

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.

Acute carnosine and β-alanine supplementation increase the compensated part of the ventilation versus work rate relationship during a ramp incremental cycle test in physically active men.

Background: Chronic supplementation with carnosine and β-alanine (Carn-βA) has been proposed to improve muscle contractility and reduce muscle fatigue mainly through an increase in intracellular pH buffering capacity. However, the acute ergogenic effects of Carn-βA supplementation are poorly investigated. This study aimed at evaluating the acute effects of a single Carn-βA supplementation on the cardiorespiratory and metabolic response during a ramp cycle-ergometric test.

Neuromuscular versus Mechanical Stretch-induced Changes in Contralateral versus Ipsilateral Muscle.

Purpose: Whether or not the homologous contralateral muscle (CM) undergoes stretch-induced force reduction as the stretched muscle (SM) is still unclear. The neuromuscular and mechanical factors underlying the force reduction in CM and SM were investigated.

Methods: Twenty-one participants underwent unilateral knee extensors passive stretching.

Quadriceps and Gastrocnemii Anatomical Cross-Sectional Area and Vastus Lateralis Fascicle Length Predict Peak-Power and Time-To-Peak-Power.

: The current study investigated the role of quadriceps and gastrocnemii size and and muscle architecture in peak-power and time-to-peak-power exerted in an all-out Wingate test. Twenty-one amateur cyclists were recruited. : Quadriceps and gastrocnemii anatomical cross-sectional area (ACSA), and and pennation angle and fascicle length were measured using ultrasound.

Evidence of Improved Vascular Function in the Arteries of Trained but Not Untrained Limbs After Isolated Knee-Extension Training.

Vascular endothelial function is a strong marker of cardiovascular health and it refers to the ability of the body to maintain the homeostasis of vascular tone. The endothelial cells react to mechanical and chemical stimuli modulating the smooth muscle cells relaxation. The extent of the induced vasodilation depends on the magnitude of the stimulus.

Heart and musculoskeletal hemodynamic responses to repetitive bouts of quadriceps static stretching.

The role of sympathetic and parasympathetic activity in relation to the repetitive exposure to static stretching (SS) on heart and musculoskeletal hemodynamics in stretched and resting muscles is still a matter of debate. The aim of the study was to determine cardiac and musculoskeletal hemodynamics to repetitive bouts of unilateral SS. Sympathetic and parasympathetic activity contribution to the central hemodynamics and local difference in circulation of stretched and resting muscles were also investigated.

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).

Respiratory muscle training positively affects vasomotor response in young healthy women.

Vasomotor response is related to the capacity of the vessel to maintain vascular tone within a narrow range. Two main control mechanisms are involved: the autonomic control of the sympathetic neural drive (global control) and the endothelial smooth cells capacity to respond to mechanical stress by releasing vasoactive factors (peripheral control). The aim of this study was to evaluate the effects of respiratory muscle training (RMT) on vasomotor response, assessed by flow-mediated dilation (FMD) and heart rate variability, in young healthy females.

Heart rate and pulmonary oxygen uptake response in professional badminton players: comparison between on-court game simulation and laboratory exercise testing.

Purpose: Badminton is characterized by bouts of high intensity interspersed by short recovery periods. Aerobic assessment via indirect calorimetry is impractical on court because of the encumbrance of portable metabolic devices. When the relationship between heart rate (HR) and pulmonary oxygen uptake [Formula: see text] [Formula: see text] is linear, HR monitoring can provide an indirect estimation of metabolic demands on court.

Sex-Related Responses to Eccentric-Only Resistance Training in Knee-Extensors Muscle Strength and Architecture.

Purpose: The present study aimed to investigate whether or not eccentric-only training induced different sex-related adaptations in vastus lateralis muscle architecture and knee extensors strength.

Methods: Thirteen healthy women and 13 healthy men were recruited. Vastus lateralis pennation angle, fascicle length, and muscle thickness, as well as knee extensors eccentric, isometric, and concentric peak torque and one-repetition maximum (1RM) were measured.

Specific Adaptations in Performance and Muscle Architecture After Weighted Jump-Squat vs. Body Mass Squat Jump Training in Recreational Soccer Players.

Coratella, G, Beato, M, Milanese, C, Longo, S, Limonta, E, Rampichini, S, Cè, E, Bisconti, AV, Schena, F, and Esposito, F. Specific adaptations in performance and muscle architecture after weighted jump-squat vs. body mass squat jump training in recreational soccer players.

Acute effects of direct inhibitory pressure over the biceps brachii myotendinous junction on skeletal muscle activation and force output.

Force (F) reduction is reported with myotendinous junction (MTJ) manipulation. Autogenic inhibition reflex (AIR) activation is supposed to be the main mechanism. Still, its role remains unclear.

Central and peripheral responses to static and dynamic stretch of skeletal muscle: mechano- and metaboreflex implications.

Unlabelled: Passive static stretching (SS), circulatory cuff occlusion (CCO), and the combination of both (SS + CCO) have been used to investigate the mechano- and metaboreflex, respectively. However, the effects of dynamic stretching (DS) alone or in combination with CCO (DS + CCO) on the same reflexes have never been explored. The aim of the study was to compare central and peripheral hemodynamic responses to DS, SS, DS + CCO, and SS + CCO.

Effectiveness of Exercise- and Cognitive-Based Treatments on Salivary Cortisol Levels and Sundowning Syndrome Symptoms in Patients with Alzheimer's Disease.

Sundowning syndrome (SDS) in patients with Alzheimer's disease (AD) is characterized by the intensification of behavioral disorders at sunset. Despite SDS etiology being unclear, a strong relationship between high cortisol levels and SDS has been reported. Aerobic exercise (AE) and cognitive training (CT) can reduce cortisol levels.