2005; Hosey, Glazer, 2004) This short review is dedicated to the issues associated with thermoregulation and dehydration influence athletic capacity during endurance events.The specific changes in the organism of athletes (Reilly, Drust, Gregson 2006; Morris et al. 2005, etc) provide the perfect adaptation to the usual environment however in extreme environmental conditions the heat or cold stress can occur and cause serious health problems (Murray, 1998; Kains et al., 1983). The conditions include heat stroke, heat cramps, heat exhaustion, heat oedemas, cardiac events and gastrointestinal symptoms (Murray, 2006; Moses, 2005; Weinmann, 2003; Hedley, Climstein, Hansen, 2002)There is well known that during exercises the metabolism is changed. Prolonged sport training is characterized with the increase of fatty acids oxidation and decrease in carbohydrates oxidation. These changes are supported by the hormonal influences (epinephrine, thyroid hormones, insulin and glucagon). Oxidation of carbohydrates leads to the production of lactic acid and fat oxidation is a source of acidic products thus acidosis can occur (Coyle, 1999; Durkot et al. 1995; Gordon et al., 1985). On the other hand high breathing rate during exercises can cause the condition of respiratory alkalosis (White, 2006). Physical endurance is characterized by the homoeostatic balance and the improved adaptive abilities (Reilly, Drust, Gregson, 2006)....
Usually he most of the heat (40%) organism loses by the emitted radiation, 30% - by convection and conduction (Varghese, Pati, 1996; Nagashima, 2006). This pattern is changed during vigorous physical activity: up to 80% of heat is lost by the evaporation (Reilly, Drust, Gregson, 2006). During prolonged heavy exercise as well as in the extreme environmental conditions body temperature deviates because of the misbalance between heat production and heat losses (ibid). Consequently the ratio between different physical mechanisms of the thermoregulation is altering.
Heat conduction involves the direct transfer of heat energy between the different materials (e.g. human body and cool water) through direct molecular contact (Pezzagno, 1999). Contrarily to this convection is the circulatory motion that occurs in a fluid at a non-uniform temperature owing to the variation of its density and the action of gravity (ibid). This mechanism of thermoregulation is important for the premises or open areas with high velocity of air movement (Saunders et al., 2005). Radiation is the process of emitting radiant energy in the form of electromagnetic waves (i.e. infrared radiation). It is the primary method for discharging the body's excess heat. Its effectiveness depends on the endurance of cardiovascular system - the peripheral hyperaemia in poorly trained person can cause "steal syndrome" and syncope (Natarajan, Nikore 2006; Seto, Way, O'Connor 2005), and on the external infrared radiation from the sun or heated surfaces (Peiser, Reilly., 2004). If the temperature of the surrounding objects is greater than skin temperature thus the body will