Answer:
The body looses huge amount of water and salts from the body at the time of exercising.
Enough amount of salts is excreted out of the body which needs to be compensated after exercise. Taking plain water will not maintain balance in the body.
It needs electrolytes along with plain water as sodium is important for the body. If the body intakes lots of plain water without electrolyte and this condition is known as hyponatremia.
