Hyperthermia. New Thoughts on an Old Problem,

In this article, the common heat illnesses heat syncope, salt-and water depletion-heat exhaustion and exertion-induced heatstroke are briefly reviewed from the perspective of their underlying physiological disturbances, which provide a rational basis for therapy. Due to an apparent paradox between the current clinical dogma and laboratory data, however, the evaluation of the consequences of hyperthermia is extended beyond the usual systematic approach. This raises two new questions what translates heat stress into heat strain at the level of the cell, and is a mechanism identifiable A new hypothesis, based upon experimental research, is offered which suggests that a series of factors operate in exercise-induced hyperthermia to increase the permeability of the cell membrane, primarily to sodium ions. This stimulates sodium-potassium ATPase the Sodium Pump and results in an inefficient energy drain upon the cell the Energy Depletion Model. This concept takes the form of a vicious circle leading to increased heat production and storage, reduced exercise-heat tolerance and significant morbidity and mortality. This model predicts that cellularmetabolic processes and deficits operate for some time after hyperthermia has subsided with cooling. Keywords Ion channels Physiological effects.