Edited by Dr. Gianfranco De Angelis
Exercising a "physical activity is very important. The body needs to work, as it can be a prolonged state of rest that causes illness."
Exercise improves health by increasing the function of various physiological processes. Some even claim that athletic activity extends life.
The heart is like a pump, whose fundamental task in the "economy of the organism" is to supply all cells with oxygenated blood, essential for them to carry out their metabolic functions. The heart provides the necessary force for the progression of the blood, which in turn carries the nourishment to all parts of the body by taking away the waste products resulting from the metabolism. The substances most conveyed are oxygen, carbon dioxide, lactic acid and glucose. Thanks to its rhythmic contraction, the heart sends blood both to the pulmonary circulation, where respiratory exchanges take place (for which the red blood cells release all "external carbon dioxide enriching with oxygen), both in the systemic circulation, to fulfill metabolic functions.
Cardiac activity, made up of systole and diastole, is carried out by the action of central and peripheral nervous structures, independent of the will, which carry stimuli to the heart. The heart is therefore an indefatigable machine, whose eventual arrest, even for a few seconds, causes irreversible damage to the most sensitive and oxygen-requiring cells, such as those of the nervous system. From this simple observation it is possible to understand the importance of this organ for the purpose of perfect physical efficiency, but also the need to treat it with due caution, especially in relation to physical activity.
The heart adapts to physical work with functional changes, which result in an increase in heart rate and systolic output, therefore in cardiac output or output (amount of blood expelled in one minute). Being a resistance muscle, the range adaptation mechanism is compensated by an increase in the length of the cardiac fibers, directly proportional to the strength of myocardial contractility (Frank Starling's law). For this reason, athletes have a hypertrophic heart; depending on the type of sport, therefore the type of overload, we distinguish two types of athlete's heart hypertrophy: a "concentric hypertrophy (with symmetrical increase in the wall thickness of the left ventricle and reduction of its diameters), typical of power training with pressure overload in a short time, and an "eccentric hypertrophy with an increase in the wall thickness of the left ventricle and consensual increase in its diameters, typical of endurance sports with volumetric overload.
Cross-country athletes usually enlarge the right side (due to increased pulmonary resistance to circulation and increased venous inflow). On the contrary, short and intense efforts increase the thickness of the left heart, due to the increase in blood pressure in the systemic circulation (this phenomenon is found most often in physical culture at a competitive level).
With training, especially in cross-country sports, there is also a reduction in heart rate at rest, thanks to the development of an overtone of the vagal nervous system; all this is offset by the fact that each systolic contraction occurs in a more energetic manner.
In order for these adaptations to occur without damage, it is essential to approach the sport in a light way, and then gradually increase its intensity.
Sport and the heart: the precautions to keep it healthy "
