Dehydration is a condition of having too little water in the body. Symptoms of mild dehydration include thirst, irritability, and discomfort. Moderate dehydration is marked by headache, weakness, dizziness, cramps, chills, decreased urination and sweating, rapid heartbeat, nausea, and vomiting. Severe dehydration may cause shock and even death.
Worldwide, the most common cause of dehydration is infectious diarrhea. Dehydration resulting from diarrhea is a major cause of death among children in less developed countries. Other causes of dehydration include vomiting, excessive sweating or urination, and extensive skin burns. Athletes who exercise vigorously in the heat may lose large amounts of water through sweat and become dehydrated.
People suffering from dehydration should drink fluids to replace lost water. But drinking too much water can cause a potentially dangerous drop in blood sodium levels called hyponatremia. Severe dehydration usually requires hospitalization. Physicians often treat diarrhea-related dehydration using a solution of glucose, water, and salt, given as a drink or injection.
