The electrolyte balance can be restored at the end of the day in a meal. Lack of water can very quickly degrade performance. Experiments have shown that even drinking water 'ad lib' may not be enough to replace losses. On a hot day you really need to drink to excess. There are two groups of so-called sports drinks.
Energy drinks are most useful after an event and taken during heavy exercise can cause vomiting.
Electrolyte drinks contain small quantities of salts in isotonic concentrations. These are not to replace electrolyte losses, but to aid water absorption from the intestine, which is otherwise rather slow. In addition, during heavy exercise the gut does not work very well so large amounts of neat water can pass straight through. Rather than buy an electrolyte drink you can mix up your own powder. This is the salt and glucose solution given to babies with diarrhoea.