According to I. A. Arshavsky"s “energy rule of skeletal muscles”, the energy potential of the organism and the functional state of all organs and systems depend on the nature of skeletal muscle activity. The more intensive the motor activity within the optimal zone, the more fully the genetic program is realized and the more energy potential, functional resources of the organism and life expectancy increase. A distinction is made between the general and special effects of exercise, as well as its indirect effect on risk factors. The most common effect of exercise is energy consumption, which is directly proportional to the duration and intensity of muscular activity, which allows you to compensate for the lack of energy consumption. It is also important to increase the body"s resistance to adverse environmental factors: stressful situations, high and low temperatures, radiation, injuries, hypo.
As a result of the increase in non-specific immunity increases and resistance to colds. However, the use of maximum training loads necessary in sports to achieve the “peak” of the sports form, often leads to the opposite effect — the suppression of immunity and increase susceptibility to infectious diseases.
A similar negative effect can be obtained in the case of mass physical activity with an excessive increase in workload. The special effect of recovery training is associated with increased functionality of the cardiovascular system. It consists in saving the heart"s work at rest and increasing the reserve capabilities of the circulatory system in muscular activity. One of the most important effects of physical training is the reduction of heart rate at rest (bradycardia) as a manifestation of the reduction of cardiac activity and lower oxygen demand in myocardium. Increasing the duration of the diastolic phase (relaxation) provides a larger bed and a better oxygen supply to the heart muscle. People with bradycardia have a significantly lower incidence of CHD than people with a high pulse rate. A 15-ud/min increase in heart rate at rest is thought to increase the risk of sudden death from a heart attack by 70% — the same pattern is observed in muscle activity. When performing a standard load on a veloergometer, trained men have almost 2 times less coronary blood flow than untrained men (140 vs. 260 ml/min per 100 g of myocardial tissue), respectively, and twice less oxygen demand for myocardial tissue (20 vs. 40 ml/min per 100 g of tissue).
Thus, as the level of training increases, myocardial oxygen demand decreases both at rest and at sub-maximum loads, which indicates the saving of cardiac activity. This fact is a physiological justification for the need for adequate physical training for patients with ICS, because with the growth of training and reduced oxygen demand for myocardium increases the level of threshold load, which the subject can perform without the threat of myocardial ischemia and angina attack. The most pronounced is the increase in the reserve capabilities of the circulatory apparatus in case of intensive muscular activity: increase in the maximum heart rate, systolic and minute blood volume, arterial and venous oxygen difference, reduction of total peripheral vascular resistance (TPVD), which facilitates the mechanical work of the heart and increases its productivity. Evaluation of functional reserves of the circulatory system at maximum physical activity in persons with different levels of physical condition shows: people with average UFS (and below average) have minimal functional capabilities, bordering on pathology, their physical performance is below 75% DMCP.