<P> In most athletes, exercising and sweating for 4--5 hours with a sweat sodium concentration of less than 50 mmol / L, the total sodium lost is less than 10% of total body stores (total stores are approximately 2,500 mmol, or 58 g for a 70 - kg person). These losses appear to be well tolerated by most people . The inclusion of some sodium in fluid replacement drinks has some theoretical benefits and poses little or no risk, so long as these fluids are hypotonic (since the mainstay of dehydration prevention is the replacement of free water losses). </P> <P> The consumption of overly sugary and / or salty foods can cause dehydration . </P> <P> The treatment for minor dehydration that is often considered the most effective is drinking water and stopping fluid loss . Plain water restores only the volume of the blood plasma, inhibiting the thirst mechanism before solute levels can be replenished . Solid foods can contribute to fluid loss from vomiting and diarrhea . Urine concentration and frequency will customarily return to normal as dehydration resolves . </P> <P> In some cases, correction of a dehydrated state is accomplished by the replenishment of necessary water and electrolytes (through oral rehydration therapy or fluid replacement by intravenous therapy). As oral rehydration is less painful, less invasive, less expensive, and easier to provide, it is the treatment of choice for mild dehydration . Solutions used for intravenous rehydration must be isotonic or hypertonic . Pure water injected into the veins will cause the breakdown (lysis) of red blood cells (erythrocytes). </P>

Which type of dehydration results from water loss in excess of electrolyte loss