Hydralyte may be taken on the first signs of fluid loss due to vomiting and diarrhea. Hydralyte may also be taken to help manage dehydration due to the loss of fluids through heavy sweating. This can be caused by fever, endurance exercise, prolonged heat exposure or prolonged physical work. Water / sugary drinks vs Hydralyte. Water or sugary drinks (i.e. soda or standard sports drinks) are not as effective as Hydralyte, as they do not adequately restore lost electrolytes (which retain the fluid). Sports drinks also contain a lot of sugar (approximately 4 times the amount compared with Hydralyte!) ƒ?? Excess sugar can cause bloating and impede the hydration process.