[Mechanisms of extreme states in human]

Pathogenesis of extreme states during hypoxic hypoxia, exogenic and combined hyperthermia, aerial and immersion hypothermia is mainly associated with deterioration of reactivity and decline of functional reserves of the neuroendocrinal system, energetic dysbalance against more pronounced signs of anaerobic catabolism and recruitment of plastic resources of the body, activation of peroxide oxidation of lipids (POL), depletion of AOS potential with labilization of cellular membranes, and progressing changes in structural and functional relations within the antigenous/structural homeostasis. The determinacy of extreme state is influenced by initial status of the body functioning. The bodily extreme state has been found to depend on severity of asthenisation, peculiarities of the autonomous regulation, metabolic and immune status. Partial or full reversibility of decompensation disorders distinguishes extreme state from the critical (predeterminal) one. The relative adequacy of compensation and the principal possibility of a beneficial result are the necessary conditions for extreme state verification. Otherwise, in the lack of time for effective compensation typical syndromes of critical states may develop already during acute adaptation. There can develop partial insufficiency of a dominating functional system which will be compensated at the sacrifice of other organs and tissues. Sometimes extreme state may result in development of marginal or pathological states with human living activities preserved.