Your blood normally contains around 140 mmol/L of sodium, and smaller amounts of calcium, magnesium, and potassium. Sodium is the most important of these and has the narrowest normal range (135-145 mmol/L). Except for calcium (which can be taken from your bones) there is little storage. In normal circumstances you don’t lose much water and can get sufficient electrolytes from food, but during fever your fluid loss rate can easily be increased by multiple liters per day, and you may be eating much less as well.
Probably stupid question, but why electrolyte drinks rather than just water?
Your blood normally contains around 140 mmol/L of sodium, and smaller amounts of calcium, magnesium, and potassium. Sodium is the most important of these and has the narrowest normal range (135-145 mmol/L). Except for calcium (which can be taken from your bones) there is little storage. In normal circumstances you don’t lose much water and can get sufficient electrolytes from food, but during fever your fluid loss rate can easily be increased by multiple liters per day, and you may be eating much less as well.