Functions of the immune system
are its resistance to infection (the classical function), destruction of tumor cells and participation in regeneration of the tissue. The immune resistance is a task, which concerns the whole organism. Primary lymphatic organs are the thymus gland and the bone marrow. Here the immune cells are formed and spread after their maturation in the blood, the lymph and the tissue of the other organs. Secondary lymphatic organs for example are the regional lymph nodes, the spleen and the pharyngeal tonsils. In these tissues respectively organs the immune a cells settle down. Immune organs are as well the intestine, the skin, the liver and the lung. The unspecific immune reaction as a first defence front is divided into a cellular (macrophages, granulocytes) and a humoral (complement system, other serum proteins) component. The specific immune reaction is a custom made protection against every pathogen by b- and t-lymphocytes after activation of the macrophages (antigen-antibody-reaction according to the key-locker-principle). With the help of the memory cells the immune system recognizes former pathogens. Thus the immunologic memory allows a faster reaction. Immune messenger substances (cytokines) and surface structures (adhesion molecules) regulate the distribution and activity of immune cells in the organism. The interaction of endothelium cells (inner cell layer of vessels) and leukocytes (white blood cells) has a decisive importance for the regulation of immune reactions like inflammation. A healthy immune system is a requirement for physical fitness also for the aged.
Immune system and sports
The increased mechanization with its reduced physical stress and increased lack of physical exercise in daily life in combination with aging leads often to a limited aerobic power. Those concerned are not able to run slowly or even walk quickly longer distances. From this results an increased incidence of arteriosclerotic cardiovascular diseases, overweight, degenerative changes in the locomotor system and the spine (lacking power and coordination). Inactivity also enhances premature aging processes of the central nervous system, the endocrine and immunologic system (decreased training of antioxidant mechanisms). This correlates with the fact, people taking part in sports show a decreased incidence of tumor disease and infections, if the sporting exercise is done regularly over a longer period of time. It has to be noticed, that also “too much” of physical activity (e.g. the small group of powerful competitive athletes, who are able to bring forth their personal top output at the border to overtraining) presents a problem to the immune system. This is indicated for instance by an increased frequency of upper airway infections. This weakening of the immune function affects as well health as the ability of the single person to regenerate and perform.
Basic principles of training and adaptation
Physical activity is limited naturally by the anatomy and physiology of the locomotor system, because thereby active and passive structures of the locomotor system are stressed by mechanical and metabolicy means. While moving the energy pool empties increasingly (metabolism), whereas simultaneouslythe passive and active elements of the locomotor system are exposed a simultaneous stress by traction, pressure and torsion. This leads to a tiredness, which can be indicated by depletion of the energy pools, overuse reactions either of the locomotor system or the central nervous system. The fundamental principle of increasing performance by training is based on repeated and regular stress, tiredness and regeneration ending up in a supercompensation. By this the strained structures are strengthened in order to be equal to new stress. Intensity and duration of stress determine the period of time needed for tiredness and regeneration : short strains require a short, long strains a long period of time. As mentioned before, the most frequent mistake in training is inadequate regeneration during a close follow-up of training units. Apart from reduced or absent improve in performance there is an increased occurrence of overuse injuries concerning the locomotor system or overtrained syndromes, which weaken the immune system (e.g. by increase in acute airway infections etc.). In addition to the organization and execution of a reasonable training schedule a protective effect is given by high-dose intake of vitamine C and other antioxidants.
Cause and effect
Increasing training intensity the risk grows to be taken sick from an infection of the upper airways. This is typical especially for competitive athletes. Basicly a higher extent of training is tolerated better than an increase of intensity (intensive training units, competitions). Very long acting and anaerobic strains, which increase the lactate level in blood, but also the psychologic stress and poor supply with essential substances take a negative effect here. As a possible cause for reduced immune function reduced leucocyte numbers (competitive athletes) are described. In addition functional changes of leucocytes e.g. in the form of decrease in oxygen radicals being produced. Controling training by immunologic parameters is not possible at the moment. Hobby sportsman/women training endurance moderately show a decreased incidence of airway infections. Here especially moderate extents of training (e.g. running 25 km a week) have proven its worth. Only a few examinations dealing with hobby sportsman/women have shown significant changes of laboratory parameters (e.g. increase of immunoglobulines or protease inhibitors like the alpha-1-antitrypsin). In order to achieve optimal training effects a balanced nutrition is required. By this the supply with essential substances can be assured generally. The emphasis should be on carbohydrates, the supply with fluid and calories must be sufficient. Both the competitive athlete and the hobby sportsman/woman need a higher amount of micro nutrients caused by increased losses of sweat, stool and urine. Substitution of mineral substances, trace elements and vitamins especially in case of suboptimal nutrition is recommended. After exhausting strains, especially under hot weather conditions, the supply of potassium, magnesium and enough fluid is necessary. When substituting high doses of antioxidant substances (selen, vitamin C and E) besides the relief of the immune system additional side effects on the prevention of degenerative processes e.g. arthroses of the joints are discussed. The trace element zinc plays a role in almost every immune reaction. Zinc stimulates lymphocytes, activates phagocytes (scavenger cells), increases the release of cytokines and activates the complement system. Absence of zinc paralyses the immune defence. Using certain laboratory parameters the immunologic state can be controlled. Regular and adapted training delays degenerative processes caused by the immune system, the cardiovascular system and the locomotor system. For this mainly endurance sporting activities are suitable, which are done below the anaerobic threshold. After exclusion of pre-existing damages (coronary heart disease by ECG, orthopedic disabilities by sports medicine exam) ideally a long-standing endurance training (walking, biking, swimming) should be done. This training can be combined with sporting games in order to improve (because more varied) the sporting compliance and the personal well-being