Khankeldiev Sh. Kh. Regional features of the physical status of youth students fergana 2022 Reviewer

1.10. FEATURES OF HEAT REGULATION IN CHILDREN
The subject of our many studies was the study of the organization and methods of physical education of children and students at high external temperature.
Considering that many of our subjects have not yet reached the state of full physiological maturity, it obviously makes sense to analyze the special literature related to the peculiarities of thermoregulation and heat transfer. Children, in a number of respects, differ significantly from adults and, above all, draw attention to the differences of a geometric nature. In children, there is much more body surface per unit of body weight. For example, in a seven-year-old child, the surface area per 2 kg of body weight is about 35-40% greater than in adults, this obviously facilitates heat transfer in cases where exercises are performed in low ambient temperatures and increases the flow of heat to the body in cases where physical exercises are performed at a temperature exceeding body temperature. Therefore, when performing physical exercises in conditions of high external temperature exceeding body temperature, children are in very unfavorable conditions.
It is necessary to take into account that energy costs when walking and running at the same speed are significantly higher in children than in adults. These differences can reach 20-30%. Moreover, differences in heat production in children and adults when performing the same physical exercises remain regardless of the ambient temperature. In particular, when performing exercises in conditions of high ambient temperature, children have more energy consumption. The end result of this is that children produce more heat when doing the same physical work.
In addition, children have a lower rate of sweating, both per unit of body surface and by total indicators. The reason is not the lower density of sweat glands, as it was once assumed, but the lower productivity of the existing sweat glands in children. Although it may be thought that a smaller amount of sweating is a factor that limits the performance of children, it is impossible to exclude the possibility that the evaporation of sweat from the body of a child may be more effective than from the body of an adult, especially in cases when, as happens when performing exercises in conditions of high temperature and humidity of the environment, there is excessive sweating.
According to the level of heat production, the minute volume of the heart in children is significantly lower than in adults, both in conditions of comfortable ambient temperature and when performing exercises in conditions of high ambient temperature.
Since a decrease in the amount of minute blood volume has the consequence of a decrease in the amount of subcutaneous blood flow during exercise, it can be assumed that heat loss as a result of convective processes, namely, as a result of heat transfer from the core to the surface of the body, is less pronounced in children than in adults. Thus, it follows from theoretical considerations that the thermoregulatory capabilities of children, in comparison with adults, are reduced.
Experimental data indicate that children and adolescents acclimatize to exercise in conditions of high ambient temperature to a lesser extent than it occurs in adults. The rate of acclimatization in children is lower, so their acclimatization time is delayed for a longer period. At the same time, their subjective assessment of their condition when performing exercises in conditions of high ambient temperature changes in a positive direction much faster than adults. Thus, there is a discrepancy between the actual degree of adaptation of the child's body to an increase in body temperature and subjective sensations.
In children, the vast majority of heat strokes are observed at the beginning of summer, after a sudden rise in ambient temperature and, as a rule, on the first or second day of exercise in conditions of high ambient temperature, when, obviously, the child's body has not yet had time to acclimatize to these new conditions.
The practical consequence of the above is that you should avoid any competitions associated with heavy physical exertion in the second half of May and in the first half of June, when the body of children has not yet had time to acclimatize to high external temperature. In all cases, and especially when studying with children in conditions of high ambient temperature, the teacher should exercise caution.
As for the thermal tolerance of children, when they perform exercises, under favorable external conditions (in conditions of relatively low temperatures and humidity of the surrounding air), they thermo regulate with the same efficiency as adults. On the other hand, at high ambient temperatures, children are at a great disadvantage if they have to exercise.
Direct experimental data show that when the outside air temperature reaches 45°With or more, children are practically unable to exercise. If the air temperature exceeds 30 °, children practically do not tolerate physical exercises performed even with a relatively low intensity - 40-50% of their maximum aerobic capabilities.
The main reason for the low tolerance of children in this case is the large size of the body surface per I kg of the child's body weight, which leads to a large influx of heat from the external environment to the body. Therefore, when practicing with children, you should limit the time of exercise and be very careful in cases where the duration of the exercise exceeds 20-30 minutes. Barrow's data show that for short-term exercises, the duration of which does not exceed I minutes, possible overheating of the body is not a critical factor, and therefore such exercises can be included in the program of classes with children when such classes are held at high ambient temperature.
The available data indicate that the loss of water (as a result of increased sweating, restriction of drinking, etc.) increases the child's susceptibility to heat stroke to a greater extent than it occurs in adults. Therefore, when exercising with children in conditions of high ambient temperature, they should not be restricted in taking water, remembering that dehydration reduces the thermal tolerance of children to a much greater extent than it is the case with adults.
Summarizing the available data on the peculiarities of thermoregulation of children when performing physical exercises in conditions of high ambient temperature (Table), we can say that the thermal tolerance of children is significantly reduced in comparison with the tolerance of adults. In children, the ratio between the surface and body weight is very unfavorable (in cases where the air temperature exceeds the body temperature). Children have less ability to sweat, their acclimatization time is slowed down. In children, there is a discrepancy between the subjective assessment of their influence on thermoregulation.
The reduced possibility of heat exchange between the core and the surface of the body and the real objective state of the body, provokes the appearance of heat strokes. Dehydration of the body due to restriction of drinking in children is significantly more dangerous than in adults. Therefore, trainers and teachers conducting classes with children in conditions of high ambient temperature should remember these features of the child's body and exercise the necessary caution, especially at the early stages of acclimatization. Children should not be restricted in taking water during training sessions.
It was of particular interest to study the seasonal dynamics of changes in the functional changes of the body of students engaged in selected sports. The high perfection of the execution of complex coordinated motor acts during physical exercises is ensured by the strictly coordinated activity of the central nervous system.
The information about the functional state of organism of young athletes in the climatic conditions of our region is of particular relevance. The effects of applied physical exertion in combination with climatic factors cause certain changes, which are most pronounced in the direction of disinhibition or inhibition of the knee reflex in young athletes.


Table 2
Some morphological and physiological features of children and their influence on thermoregulation