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Essential hypertension, a disease in which elevated arterial blood pressure is associated with normal values of cardiac output (the amount of blood pumped by the heart in one minute), has a remarkable health impact on our societies. High blood pressure is the leading risk for mortality in the world, because it increases the risk for cardiovascular diseases, causing more than 7 million deaths (some 13% of deaths globally) every year worldwide. The control of essential hypertension is thus of primary importance in medical systems’ strategy to prevent cardiovascular accidents. Current behavioural measures and pharmacological treatments have remarkably improved the clinical control of essential hypertension. Nevertheless, shedding light on the physiopathology of this disease will add much to our understanding of its causes and to the measures that could be taken. In the last ten years, huge efforts were made to understand the genetic aspects of essential hypertension, yet with poor results: although a genetic component in essential hypertension is highly probable, the genetics of hypertension is very complex and hard to disentangle yet. Recent results on the neural regulation of renal function have led to re-emphasize the role of neural mechanisms in the genesis of essential hypertension. On this basis, we postulate that patients affected by essential hypertension are characterised by a different functional organisation of the neural system controlling circulation (the forefront of blood pressure control) from that of normal heallthy individuals. If this is so, the study of the cardiovascular response to exercise in hypertensive patients would provide important information on the subject, because a re-organisation of the neural control system of cardiovascular function would translate into measurable differences in i) the steady state level of selected cardiovascular parameters during moderate intensity exercise, and ii) the characteristic parameters describing the rapid cardiovascular adjustments upon exercise onset. Thus, the aim of this project is to investigate with contemporary non-invasive techniques the steady-state and the dynamics of the cardiovascular response to exercise in patients affected by essential hypertension and compare them with those obtained in healthy control subjects of similar age, sex and physical fitness. In particular, we will perform a quantitative analysis of i) the haemodynamics of the oxygen transport system at the steady state of submaximal exercise, upright and supine (steady state study) and ii) the the kinetics of heart rate, cardiac output, mean blood pressure and pulmonary oxygen uptake at exercise onset, upright, supine and under exposure to lower body negative pressure (a tool allowing precise control of the amount of blood that at rest is displaced from the thoraxo the lower limbs). As a counterpart of hypertensive patients, we will extend the tests to patients affected by chronic orthostatic intolerance, who are situated on the opposite side of the blood pressure regulation spectrum. The results of this project will improve our view of the neural mechanisms involved in the cardiovascular regulations during exercise. But most importantly they will contribute to shedding light on the origin of essential hypertension and eventually designing novel, more targeted strategies of exercise administration as a preventive and therapeutic tool.
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