Heart and sport

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 due to illness.

Exercise improves health by increasing the function of various physiological processes. Some even claim that athletic activity lengthens life.

Although this is disputed by many, there is no doubt that an activity that is not excessively strenuous is an advantage for health. Very often it is possible to note some organic improvement with the simple resumption of physical activity in sedentary subjects. The movement determines a sense of physical well-being, allowing us to release the nervous tension, especially in psycho-neurotic individuals. In addition, it fights insomnia, maintains an ideal weight, serves to develop muscle mass without imbalance, to remove or reduce structural disharmony and to remove some diseases that more easily affect weaker physicists (respiratory tract disorders in cold weather, disorders digestive resulting in headaches etc.). But above all, physical activity can exert an energetic prophylactic action against the cardiovascular system, of which the heart is the main element.

The heart is like a pump, whose fundamental task in the economy of the organism is to supply all cells with oxygenated blood, which is essential for them to fulfill their metabolic functions. The heart supplies the strength necessary for the progression of the blood, which in turn transports the nourishment to all parts of the body taking away the waste products deriving from the metabolism. The most widely conveyed substances are oxygen, carbon dioxide, lactic acid and glucose. Thanks to its rhythmic contraction, the heart sends blood both into the pulmonary circulation, where respiratory exchanges take place (whereby the red blood cells release carbon dioxide on the outside, enriched with oxygen), and in the systemic circulation, to fulfill metabolic functions.

Cardiac activity, made up of systole and diastole, is achieved by the action of central and peripheral nervous structures, independent of will, which carry stimuli to the heart. The heart is therefore an indefatigable machine, whose eventual arrest, even for a few seconds, causes irreversible lesions to the most sensitive cells and those most in need of oxygen, such as those of the nervous system. From this simple observation one is able to intuit 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 modifications, which result in an increase in heart rate and stroke volume, therefore in the range or cardiac output (quantity of blood expelled in one minute). Being a resistance muscle, the mechanism of adaptation of the range 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 hypertrophy of the athlete's heart: concentric hypertrophy (with symmetrical increase in 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 increased parietal thickness of the left ventricle and consensual increase of its diameters, typical of endurance sports with volumetric overload.

Cross-country athletes normally enlarge the right side (for increased pulmonary circulation resistance 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 most often found in physical culture at a competitive level).

With training, especially in cross-country sports, a reduction in resting heart rate is also appreciated, thanks to the development of a hypertonus of the vagal nervous system; all this is compensated by the fact that every systolic contraction occurs more energetically.

In order for these adaptations to occur without damage, it is essential to approach the sport lightly, and then gradually increase its intensity.

Sport and heart: precautions to keep it healthy »