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

1.11.1. ACCLIMATIZATION TO HEAT
According to the data of many studies, in order to successfully perform physical exercises in conditions of high ambient temperature, it is necessary to pre-acclimatize those engaged, and, in particular, athletes. It follows from many studies that the main acclimatization changes occur during the first week of acclimatization, and acclimatization to heat almost completely ends by the end of day 10. Within 9-10 days, acclimatization is almost completed. Studies also show that acclimatization requires thermal exposure in the range of 2 to 4 hours per day. From a practical point of view, this means that when moving to a hot climate, the first training sessions should be light in load and last within 15-20 minutes.
A very significant question is whether acclimatization to heat can be replaced by physical training conducted in comfortable conditions. According to the data of the studies mentioned in the previous sections, to some extent this is possible, since it has been shown that persons with high aerobic performance more easily tolerate heat loads than untrained persons, or representatives of those sports in which endurance exercises are insufficiently represented. However, it follows from the data of the same studies that this acclimatization is not completely complete, and representatives of endurance sports in cases where they are required to demonstrate their highest achievements must also undergo a certain period of thermal adaptation.


CHAPTER 2. THERMAL ADAPTATION AND ITS SIGNIFICANCE AT THE STAGE OF PHYSICAL IMPROVEMENT


2.1. FEATURES OF HEAT REGULATION DURING MUSCULAR EXERTION
The contraction of muscle tissue is accompanied by the formation of heat, the amount of which depends on the intensity and duration of muscle work. If heat transfer is difficult, muscle heat generation can cause an increase in body temperature to pathological limits within a relatively short period of time. If, with moderate muscular work in the form of walking and an air temperature of plus 38 degrees C. exclude the evaporation of sweat from the surface of the body with a waterproof suit, then after 20-30 minutes the body temperature increases to a critical level (more than plus 40 degrees C). With high-intensity physical exercises in conditions of high external temperature, the effect of an increase in body temperature can reach up to 43 degrees Celsius, indicating that muscle work is a powerful biological factor that determines the thermal balance in the body.
It should be emphasized that with intensive muscle work, prerequisites for a deep transformation of the processes of heat regulation are created. This is expressed, first of all, in an acute restructuring of the mechanisms of heat regulation in response to intense muscle work. The essence of this phenomenon consists in the mobilization of physical mechanisms of heat regulation: evaporation, heat conduction and heat emission. In the process of physical exercises, the mechanism of heat transfer by evaporation of sweat from the surface of the body acquires the greatest importance. In the case of an increase in body temperature during muscle work, there is an increase in the sweating reaction, which results in the removal of excess heat from the body. Consequently, the sweating reaction in muscle work should be considered as an important physiological indicator indicating the occurrence of the phenomenon of overheating of the body to some extent. By the intensity of sweating during physical exercises, the teacher can judge the degree of overheating of the body and, consequently, the conditions and level of heat regulation during muscle work.
As the external temperature increases during dynamic muscular work, the value of heat transfer through evaporation increases and the physiological effect of heat emission and heat conduction decreases.
With repeated muscular work, accompanied by overheating of the body, there is an adaptive restructuring of the thermoregulatory mechanisms. In the process of thermal adaptation, chemical thermoregulation changes based on the formation of new temporary nerve connections, and the resistance of nerve cells to hyperthermia increases.
Changes in chemical thermoregulation during repeated muscle work are detected in the form of a decrease in body temperature increase in response to the same or greater muscle load.
Increasing the resistance of nerve centers to thermal effects in the process of thermal adaptation is manifested in the ability of a person to perform muscular work in conditions of significant overheating of the body. With the establishment of the possibility of adapting nerve centers to the effects of high temperature, the prospects for increasing the stability of the body in conditions of limited or no heat transfer are expanding.
Thus, as a result of thermal adaptation, the improvement of physiological mechanisms of heat regulation and an increase in the resistance of nerve centers to hyperthermia is achieved, which together determines a high degree of resistance of the body to overheating.
This phenomenon is extremely important for improving athletic performance both during intensive muscle work in a normal environment and during motor efforts in conditions of high external temperature.
Functional shifts in the body during muscular work in conditions of high external temperature
When performing intensive muscle work in conditions of high external temperature, there is a tendency to a rapid drop in performance. The immediate cause of this is a sharp disorder of vital functions of the body due to violations of the thermal balance.
A characteristic feature of the body's reactions, with intense muscular work in conditions of high external temperature, is the deterioration of higher nervous activity, manifested in a decrease in memory, will, the appearance of apathy, imbalance of nervous processes, disorder of differentiated motor reactions, etc. These shifts in higher nervous activity are accompanied by a decrease in human motor ability and, first of all, adversely affect the regulation of complex coordination of voluntary movements. The specific nature of the effect of physical exertion on the body at high external temperature is manifested in the activity of the cardiovascular system.
At the same time, it is essential that with intense muscular work in conditions of overheating of the body, perfectly healthy people, but insufficiently adapted to motor activity in difficult conditions of thermoregulation, may develop an adverse reaction of the circulatory organs. This is manifested in an excessive or insignificant increase in heart rate and maximum arterial blood pressure after exercise, or in their fall below the baseline level. At the same time, people who are well prepared to perform muscular work at high external temperature develop high functional activity of the cardiovascular system.
Prolonged work in conditions of high external temperature causes a complex course of bioelectric phenomena of the heart. In particular, sinus tachycardia persists for a considerable time after exertion, which indicates that the intense activity of the heart continues after exertion. In addition, after work accompanied by overheating of the body, there are cases of slowing of intraventricular conduction.
It should be emphasized that with intensive muscle work, in conditions of high external temperature, overstrain of the heart muscle and a decrease in the functional capabilities of the heart may occur for a short period of time.
Muscle work, which takes place under conditions of significant overheating of the body, is accompanied by deep shifts in hematopoiesis. The physicochemical processes occurring between the plasma and the shaped elements of the blood change significantly during intense muscular work under conditions of overheating of the body. In this regard, the question of the intensity of the process of leukocytosis (degeneration of leukocytes) deserves special attention.
The intensity of leukocytosis is judged by the number of Botkin-Gum Precht bodies, which represent the remains of destroyed leukocytes.
After repeated significant muscle loads at high external temperature, in experiments with limited heat transfer, cases were observed when up to 1/3 of all leukocytes were in a state of decay.
The indicator of the intensity of leukocytosis is an important objective criterion that characterizes the orientation of the adaptive reactions of the body during muscle work in conditions of high external temperature and intense solar radiation.
The profound changes in the physic-chemical processes occurring between plasma and shaped blood elements, during muscular work in difficult conditions, heat regulation, can be judged by a significant acceleration of the erythrocyte sedimentation reaction, which in some cases reaches 40 mm. in 1 hour or more.
An exceptionally large functional load with intensive motor activity and difficulty in heat transfer falls on the excretory system. Sweating increases sharply during muscular work in conditions of high external temperature, when sweat losses during intense muscular work, accompanied by a sharp overheating of the body, can reach 55 g per minute.
With prolonged and repeated muscular work, coupled with difficulty in heat transfer in conditions of high external temperature, sweat loss can reach several liters per day, which is accompanied by pronounced shifts in the water-salt-vitamin balance.
The condition of the renal tissue changes significantly under the influence of prolonged intense muscle loads at high ambient temperature.
Unfavorable functional shifts in the body, formed in the process of strenuous muscular work in difficult conditions of thermal regulation when the body overheats, are associated with a noticeable decrease in the quality of motor activity: strength, speed, endurance and agility.
From the consideration of the characteristic features of the body's reactions during muscular work in conditions of high external temperature, the practically important fact follows that intensive motor activity associated with overheating of the body can cause deep shifts of vital body functions and a noticeable decrease in motor activity in relatively short periods of time.
Based on the above, it is necessary to dwell on the ways and methods of increasing the motor activity of the body in conditions of overheating.