Adaptation of the respiratory system to physical activity
The focus of adaptive changes in the respiratory system in its most General form can be reduced to finding the most perfect forms of regulation during muscular work. This search is completed with a high efficiency during low-intensity work, provide aerobic (oxygen) energy sources.
Respiration in terms of relative muscular rest in the vast majority of children of school age bears the cost of civilization” — prolonged sitting at a Desk, school Desk limits the mobility of the chest. Breathing becomes
shallow, shallow. Wellness, the value of such physiological respiration is small. The situation worsens when the child breathes through the mouth. The nose in this case is not fulfilling its bactericidal functions. The air is cleaned from dust particles, and at a low temperature and does not doubt. The subsequent chain of events completes the vicious circle: inflammatory processes in the nasopharynx doing breathing through KOs impossible or extremely difficult.
School-age children know practically nothing about the so-called full breath. The idea of deep breathing through the nose is only the initial stage of development of complete breathing. In a full breath consistently ventilated as the lower parts of the lungs and the apex of the lung. The stomach at the beginning of inhalation is lowered, freeing the aperture, and at the end of inhalation is retracted, compressing the diaphragm and providing a filling of the apex of the lung.
A deep breath followed by a full exhalation increase the efficiency of lung ventilation, increase the utilization of oxygen from exhaled air. For the full use of reserves external respiration requires special exercises that are grouped in a set of breathing exercises. To teach children and adolescents the correct, full breathing is an urgent need, a necessary condition for the preservation of health, the empowerment of adaptation to physical loads.
The systematic muscular work is formed physiologically rational perfect type of breathing. A deep breath, forced exhalation when the cyclic types of muscular work increases pulmonary and alveolar ventilation. Less ostentatiously than arbitrary pulmonary ventilation, changes under the influence of training VC. This indicator is not among the factors limiting athletic performance. However, it is posted in another important to assess the functionality of the indicator — the ratio of VC to body weight (life index).
The VC value in children 8 — 9 years is in the range of 1700 — 2200 ml. the highest vital capacity of the lungs was observed in young swimmers. At 14-15 years of age, she is 4800 — 5000 ml And 16-year increases to 5500 — 5700 ml. In athletes involved in cyclic sports, and VC is much higher than in untrained men (4.5 to 5.0 l). So, at long-distance runners VC reaches of 6.0 — 6.5 L. Life value in children less than adults, but by the end of puberty he approaches the values of adults.
Volume of pulmonary ventilation is directly dependent on the frequency and depth of breathing. The rate of breathing in newborns reaches 70 to 80 cycles per minute. Tidal volume is 15 — 20 ml. Volume of pulmonary ventilation in neonates ranges from 600 — 850 ml. one-year-old child pulmonary ventilation is increased to 3 to 4 l/min. Simultaneously there is a decrease in the relative volume of respiration (i.e., respiratory volume of air per unit of body weight. The intensity of pulmonary ventilation per unit body mass in children more than in adults.
In puberty increase the growth capacity of the respiratory apparatus. From 11 — 12 to 17-18 years pulmonary ventilation increases 1.5 times and reaches adults. When exercising external respiration is intensified in children mainly due to the increase of its frequency. The depth of breathing changes slightly. Maximal voluntary ventilation (MVV) is progressing rapidly with the systematic physical exercises. Already at the age of 9 she can reach 50 — 60 l/min, and 15 — 16 years is increased to 140— 150 l/min.
Limit values of indicators of respiratory function during exercise in children are reached more slowly than in adults. For example, during Bicycle stress test performed during the pulse rate equal to 90% of the level of adult athletes, pulmonary ventilation is only 50%, and oxygen consumption – 60% of the level of adult athletes. Because of the relatively narrow bronchial passages in children and adolescents during muscular work increases the resistance to airflow in the lungs. The consequence of this is increased energy expenditure for the work of the respiratory muscles.
High intensity of lung ventilation in children to a certain extent compensates for the lower than adults, the oxygen utilization coefficient, i.e. the ability to extract oxygen from inhaled air. In children of primary school age 1 liter of oxygen is extracted from 29 — 30 l, of an adult of L. 24-25 Insufficient efficiency of pulmonary ventilation due to how superficial and frequent breathing, and a relatively low diffusion capacity of the lungs in children and adolescents.
Increase fitness increases lung diffusion capacity. This is due to the increase in blood flow in the lung tissue, as well as with decreasing thickness of the alveolar-capillary membrane. Increasing the area of contact between the surface of the lung alveoli and the walls of the capillaries leads to accelerated transfer of oxygen in the blood.
The transport of oxygen by blood with age becomes more effective. The most distinct increase of the ability of blood to carry oxygen is observed in the pubertal period. At the same time increasing the ability of adolescents to tolerate hypoxic conditions associated with muscular work or lack of oxygen in the inhaled air (e.g., when climbing in the mountains). In 14-15 years old adolescents retain the ability to perform the work in reduced oxygenation of the blood twice in children 8 — 9 years.
Low children’s ability to tolerate hypoxic condition is that the organs and tissues of a child is worse than in adults, utilize oxygen. Therefore, the reduction of oxygen tension in the blood from them leads to oxygen starvation of tissues faster than adults. Dispose of tissues 1 l of oxygen is provided for the child by blood flow, equal to 21 -22 L. for an adult, 1 l of oxygen is extracted from 15-16 liters of blood flowing through body tissue. Therefore, hemodynamic spending (the so-called hemodynamic-ical coefficient on oxygen) on equal terms with adults oxygen supply of tissues in children above.
In children of primary school age there is increased compared with adolescents the value of the minute volume of respiration (MOU) on 1 kg mass at rest. It is they 160-170 ml/min/kg vs. 125 ml/min/kg in adolescents 13 to 14 years. 15 —17 years of age, the respiratory minute volume is reduced to IN ml/min/kg With a relative fall of MAUD rise with age absolute values of pulmonary ventilation. In terms of relative muscular rest in trained young athletes observed reduced lung ventilation.
The efficiency of respiratory function and transport function of blood in children is relatively low: oxygen regimes they are less tense than in adults. This means that children remain high reserves of increase of efficiency of respiration with age and increase fitness. Pulmonary ventilation during intense muscular work by the end of puberty is close to that of people of Mature age (100 l/min or more). On the limit possibilities of increasing pulmonary ventilation can be judged by the maximal pulmonary ventilation (MVV), defined in terms of arbitrary acceleration and deepening of breathing for 15 to 30 C.
Significant impact on the indicators of external respiration and has the character of a sports activity. The highest amount of arbitrary pulmonary ventilation and based on a 1 kg mass was observed in middle-distance runners, the smaller the sprinters and weightlifters.