This fact increases shear stress, which plays an important role in the regulation of endothelial function during exercise, such as the production of nitric oxide, which exerts a vasodilating effect. Moreover, an increase in pulse pressure takes place. The skeletal muscle releases some putative vasodilators during contractions, including potassium, adenosine, hydrogen ions, carbon dioxide, and phosphate. This small MAP increment induced by dynamic exercise takes place despite the profound SVR reduction due to the metabolic-induced vasodilatation. Dynamic exercise is characterized by a small increase in mean arterial pressure (MAP), whereas during static/isometric exercise there is a well-established progressive increase in MAP. This fact constitutes a great challenge for the cardiovascular apparatus because it would cause a drop in blood pressure, thereby impairing brain and muscle perfusion, if control mechanisms did not contemporary augment CO. Moreover, physical activities that involve large muscle mass, such as running and cycling, induce remarkable metabolic vasodilatation in the muscle vasculature, thereby reducing systemic vascular resistance (SVR). The close relation between the energetic demand of exercising muscles and cardiovascular functions is testified by the fact that during dynamic exercise cardiac output (CO) normally rises linearly as a function of O 2 uptake. One of the most studied issues in integrative physiology is how circulation is regulated during exercise, a condition where mechanisms controlling the cardiovascular apparatus have to deal with two main tasks: (1) to provide adequate oxygen to fulfill metabolic demand of exercising muscles and to guarantee metabolic end-products washout and (2) to regulate arterial blood pressure in order to maintain adequate perfusion of the vital organs without excessive pressure variations. Introduction: General View of the Cardiovascular Regulation During Exercise The regulation and integration of these reflexes operating during dynamic exercise and their possible role in the pathophysiology of some cardiovascular diseases are also discussed. The main focus of the present review will be on the central command, the arterial baroreflex and chemoreflex, and the exercise pressure reflex. In this review, we briefly summarize neural reflexes operating during dynamic exercise.
The autonomic nervous system adjustments are characterized by a parasympathetic withdrawal and a sympathetic activation. Moreover, arterial blood pressure is regulated to maintain adequate perfusion of the vital organs without excessive pressure variations. During dynamic exercise, mechanisms controlling the cardiovascular apparatus operate to provide adequate oxygen to fulfill metabolic demand of exercising muscles and to guarantee metabolic end-products washout.
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