The effect of aerobic activity in hypoxia conditions on serum interleukin 6 and interleukin 10 in active young men.

Dissertation for receiving a Master's degree (M.A

Sports Physiology Orientation

Abstract

The purpose of this research is to determine the effect of aerobic activity in hypoxia on the concentration of interleukin 6 and 10 serums were active in young men. Seven active young men with an average age of 23.33±1.56 years, weight 67.16±3.14 kg and height 176±1.76 cm participated in four sessions of aerobic activity including running for 30 minutes with an intensity of 70% of the maximum heart rate in four conditions of normoxia and hypoxia (altitudes of 2750, 3250 and 3750 meters). Blood sampling was done before, immediately after and one hour after the activity. Data analysis using the statistical method of analysis of variance with repeated measurements showed that there is no significant difference between hypoxia and normoxia in the concentration of both cytokines (P<0.05). Every four activity sessions caused a significant decrease of interleukin 6 (P> 0.05). Also, a decrease of interleukin 10 after all four activity sessions, only at the altitude of 3750 meters. It was significant (P=0.012)

Key words: hypoxia, interleukin 6, interleukin 10, aerobic activity, altitude

1-1 Introduction

One ??of the important and vital systems of the body is the immune system which is related to sports, a system that without its proper functioning, the continuation of life will be impossible (1). Because our environment is full of microorganisms that affect different parts of the body, and if different parts of this system do not serve to maintain health, the continuation of life will be problematic (3,2). Different aspects of physical activities have different effects on the components of this system, and the identification of these effects broadens our insight in understanding and interpreting the physiological mechanisms and biological reactions of the body (1). Paying attention to sports and physical activities has become an inevitable event. This attention exists at all levels of society and with different goals. On the other hand, nowadays athletes have to go on various trips to hold competitions. Such displacements may be associated with severe climate changes. Athletes who travel to high altitudes for competitions or recreational activities have actually experienced a decrease in endurance and aerobic capacity in the new geographical environment (4). Because the risk of altitude sickness increases with rapid ascent to high places, therefore, when recreational activities or competitions are held at medium or higher altitudes, measures should be taken to deal with changing weather conditions (4). Altitude means a place that is more than 1500 meters above sea level, because limited physiological effects on sports performance have been reported at altitudes lower than this level, and therefore lower altitudes are usually considered normoxia conditions and higher altitudes are hypoxic conditions (5). The composition of air gases remains constant at altitude, but the barometric pressure of the air decreases. As a result, the partial pressure of oxygen decreases and hypoxia occurs (6). Exercise and physical activity in hypoxia conditions compared to normoxia conditions affect the body with wider changes (7,8). Among these changes, we can mention the change in the immune and inflammatory responses, one of the indicators of which is the increase in the level of interleukin-6 in the plasma (9).  Interleukin-6 is a circulating multifunctional cytokine with several functions including inflammation, defense and tissue damage. This cytokine is produced by different types of tissue and cells, including immune cells, fibroblasts, endothelial cells, skeletal muscles, and adipose tissue. Interleukin 10 is a cytokine that is secreted by the activation of macrophages and lymphocytes. Since interleukin 6 has a direct relationship with interleukin 10, an increase in the concentration of interleukin 6 will cause an increase in interleukin 10 (7,8). introduced muscle-derived interleukin-6 as a true profile of exercise factors (such as duration and intensity) (7,10) that apparently increases even more than 100-fold in response to prolonged exercise (8,11,10). Interleukin 6 has profound effects on the hypothalamus and also in the hormonal regulation of exercise and training (3).The amount of plasma IL-6 increase depends on the duration, intensity, amount of muscle mass involved in the activity and endurance capacity (8,10). On the other hand, an increase in plasma interleukin-6 may be related to diseases caused by altitude, for example, chronic diseases related to altitude and water accumulation in the lungs, which can limit the capacity of physical activity (8,10). The effect of interleukin-10 is also considered by most researchers to affect immune suppression related to various forms of trauma, including physical activity (13,14). Therefore, the necessary knowledge about the increase of these two cytokines in response to training at altitude may have a positive effect on increasing the capacity of physical activity in two ways, increasing its duration and intensity. On the other hand, the research conducted at altitude has often investigated endurance and long-term exercises, and there is little information about the acute response and that too with variable altitudes. Therefore, this research intends to evaluate the effects of a session of aerobic activity on interleukin 6 and interleukin 10 in both hypoxia and neuromoxia conditions.

2-1 statement of the problem

The immune system is affected by various factors such as physical activity, and a person's health is achieved through the health of this system along with other systems (15). All the body's defense responses against new and foreign molecules take place in the immune system, which plays an important role in maintaining the body's homeostasis (16). Ensuring the health and improving the performance of athletes is one of the main goals of physical activities and sports. Therefore, coaches and athletes try to maintain the health of athletes during training and sports competition (16,17). On the other hand, a group believes that more and more intense sports activities increase the body's resistance to diseases, while scientific evidence has shown that many athletes get infected with infectious diseases, including upper respiratory tract infections, after intense training and heavy competitions (18,19,20,21). Others believe that light and moderate exercises play a decisive role in improving the immune system of the human body (22,23). What is certain is that physical activities affect different body systems and cause these systems to adapt to the specific needs of the organism during physical activity and work. Muscles, heart and blood circulation, respiratory system, kidneys and immune system are among the systems that changes in the way they work due to physical activity. In the meantime, knowing this effect as well as their controlling mechanisms is important for planning and adjusting training programs and the type of sports activity (24). In addition to their beneficial benefits, sports activities and competitions cause a temporary disruption of homeostasis due to their stressful nature, which may have destructive effects if the principles of exercise science are not followed. Among the responses of the immune system to sports activities, it has been less studied and although it has been the focus of many researchers in recent years, it is clear that there is a long untraveled road in the science of sports immunology. Exercising in different environments can have similar and even dissimilar effects on different body systems in different training conditions. The immune system and especially cytokines are no exception to this rule and can be affected by various environmental conditions. Hypoxia that exists at altitudes above sea level is one of these different environmental conditions from natural conditions that can affect the immune response. Numerous studies (25,26,27,28) have documented the effect of an activity session on the function of the immune system in normoxia conditions. Generally, according to the intensity, duration and training conditions of people, sports exercises cause different changes in the function of the immune system. However, few studies have investigated these changes in hypoxia conditions. Recently, it has been shown that when exercise is performed in two states of normoxia and hypoxia and in a similar metabolic condition (for example, in a similar condition in terms of blood lactate levels), the stimulation caused by exercise performed at altitude causes a greater increase in sympathetic activity compared to exercise performed at sea level (29). As a result, increased exercise stimulation and sympathetic activity causes an increase in the levels of interleukin 6 (as a result, an increase in interleukin 10), which is associated with an increase in circulating catecholamines (29).