Haemodynamic effect of metaboreflex activation in men after running above and below the velocity of the anaerobic threshold.
Previous studies have shown that the muscle metaboreflex, along with its effect on peripheral vasculature, is capable of inducing substantial enhancement in cardiac performance, stroke volume and cardiac output. This study was designed to determine whether the metaboreflex recruited by means of postexercise muscle ischaemia (PEMI) after running at two intensities was capable of eliciting similar enhancement in these cardiovascular parameters. In eight healthy male athletes the metaboreflex was studied with the PEMI method at the start of recovery from running bouts at a velocity of 30% above (PEMI-AV(AT)) or below (PEMI-BV(AT)) the anaerobic threshold previously assessed. Control exercise recovery tests at the same intensities were also conducted. Haemodynamics were evaluated by means of impedance cardiography. The main results were that: (1) the PEMI-AV(AT) test induced an increase in stroke volume, which was not present during the other protocol conditions; (2) the PEMI-AV(AT) test also induced a blunted heart rate response compared with the control situation, but this relative bradycardia was fully compensated by the stroke volume increment so that cardiac output was maintained and even increased in comparison with the other protocol sessions; and (3) finally, there was no detectable increase in systemic vascular resistance during PEMI-AV(AT). These results provide evidence that, like what has previously been reported for small muscle mass exercise, metaboreflex activation after running is capable of enhancing cardiac performance and stroke volume. Moreover, this study strengthens the concept that the cardiovascular response to metaboreflex is not merely the consequence of an increase in systemic vascular resistance.
Crisafulli
Antonio
A
Department of Science Applied to Biological Systems, Section of Human Physiology, University of Cagliari, Via Porcell 4, 09124 Cagliari, Italy. crisafulli@tiscali.it.
Milia
Raffaele
R
Lobina
Andrea
A
Caddeo
Manuela
M
Tocco
Filippo
F
Concu
Alberto
A
Melis
Franco
F
D000222:Adaptation, Physiological; D000328:Adult; D015308:Anaerobic Threshold; D001794:Blood Pressure; D002302:Cardiac Output; D002307:Cardiography, Impedance; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D007511:Ischemia / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000098:blood supply / Q000294:innervation / Q000378:metabolism; D009200:Myocardial Contraction; D010101:Oxygen Consumption; D005082:Physical Exertion; D012123:Pulmonary Ventilation; D012018:Reflex; D012420:Running; D013318:Stroke Volume; D013997:Time Factors; D014655:Vascular Resistance