murs was evaluated in 36 patients and the results compared with the effects of amyl nitrite and phenylephrine. The isometric handgrip exercise produced immediate, reproducible, and significant increases in heart rate and blood pressure. It also increased the intensity of murmurs due to aortic and mitral regurgitation and mitral stenosis and attenuated the murmurs of left ventricular outflow tra...

The mechanism of the pressor response to small muscle mass (e.g., forearm) exercise and during metaboreflex activation may include elevations in cardiac output (Q) or total peripheral resistance (TPR). Increases in Q must be supported by reductions in visceral venous volume to sustain venous return as heart rate (HR) increases. Therefore, this study tested the hypothesis that increases in Q, su...

Isometric exercise increases sympathetic nerve activity and blood pressure. This exercise pressor reflex is partly mediated by metabolic products activating muscle afferents (metaboreceptors). Whereas adenosine is a known inhibitory neuromodulator, there is increasing evidence that it activates afferent nerves. We, therefore, examined the hypothesis that adenosine stimulates muscle afferents an...

Myocardial oxygen supply and demand mismatch is fundamental to the pathophysiology of ischemia and infarction. The sympathetic nervous system, through α-adrenergic receptors and β-adrenergic receptors, influences both myocardial oxygen supply and demand. In animal models, mechanistic studies have established that adrenergic receptors contribute to coronary vascular tone. The purpose of this lab...

The aim of this work was to predict blood flow responses to rhythmic handgrip exercise from one second isometric contractions. Seven healthy men were studied. Each subject performed a single 1 s handgrip contraction at 10 %, 20 % and 40 % of the maximum handgrip strength. We then repeatedly summed hyperaemic responses from single contractions to predict hyperaemic response to a prolonged bout o...

The feasibility of using the cold pressor test and the sustained isometric handgrip test as alternatives to dynamic exercise for stressing the heart was investigated. Serial changes in heart rate, blood pressure, and left ventricular performance induced by these tests were studied by radionuclide ventriculography in patients with coronary artery disease and in normal volunteers. Both tests sign...

OBJECTIVE To determine whether isometric exercise increases collateral flow in remote ischaemic myocardium in acute coronary occlusion models of patients with coronary artery disease. DESIGN A randomized controlled study. SUBJECTS Sixty-five patients with 1-vessel coronary artery disease. METHODS Subjects were randomly assigned to either the isometric exercise group or non-exercise group....

Patients with coronary artery disease have attenuated coronary vasodilator responses to physiological stress, which is partially attributed to a β-adrenergic receptor (β-AR)-mediated mechanisms. Whether β-ARs contribute to impaired coronary vasodilation seen with healthy aging is unknown. The purpose of this study was to investigate the role of β-ARs in coronary exercise hyperemia in healthy hu...

OBJECTIVE To determine the effect of isometric handgrip training on blood pressure (BP) in middle-aged women (47.88 ± 1.8 years). METHODS Isometric handgrip training was performed over five consecutive days. In each session, the treatment group (n = 9) performed four isometric contractions of 45 seconds each at 30% of their maximal grip strength. The control group (n = 9) sat for 15 minutes ...