The Changes of Some Electrolytes After Two Months Activity (Report‪)‬

INTRODUCTION Sodium is the major cation of the extracellular fluid. A reduction in the extracellular sodium concentration will result in a fluid shift into intracellular space, which can lead to cellular swelling and its associated complication (12). It is overall eight to 10 times more concentrated in the extracellular than in the intracellular space. The sodium concentration gradient across the cellular membrance and the transmembrance sodium fluxes are regulated by the sodium-potassium pump, which plays an important role in cellular processes (2). Several hyponatremia (sodium 130 m mol [L.sup.-1]) has been associated with several complications, including mild symptoms, such as malaise, nausea, fatigue and confusion. Hyponatremia is seldom observed in athletes after 4 h of exercise (12). Several possible mechanisms have been postulated to lead to exercise induced hyponatremia (8). Some investigators have speculated that sodium chloride losses in sweat associated with net dehydration may lead to the observed hyponatremia after prolong strenuous exercise (12).