Water is vital to human survival. When the body loses more water than it takes in, dehydration may occur. Obvious symptoms include thirst and dry mouth or skin, but others like headache, increased heart rate, and confusion can be signs of dehydration as well. At its worst, this condition can be fatal if not addressed and treated promptly.
Since water is lost through various bodily processes like sweating or urinating, dehydration is more likely to occur with increased physical activity, in warmer temperatures, or when someone is sick (e.g., vomiting).
The good news is that most cases of dehydration can be treated by simply drinking fluids. Sometimes though, with more severe dehydration, fluids will need to be given intravenously or through the vein.