Hyponatremia is where the sodium concentration in the blood is low. This condition occurs as lost sweat, which contains salt and water, is replaced by only water during a very long distance race such as a marathon. If an athlete has hyponatremia, he/she will feel fatigued and weak, be disorientated, have muscle cramps, be nauseated, may feel dizzy and possibly faint, and worst case would have a seizure or end up in a coma. To help prevent this from happening, athletes should up their sodium intake prior to their event and after the event is over should ingest fluids such as sports drinks since they contain sodium and help to replace electrolytes.