Dehydration is when the amount of fluids your body takes in doesn't match the amount it loses. This can lead to a number of problems, the most serious of which is death.
In adults, dehydration causes a host of symptoms that range from mild to deadly. Some common symptoms include:
profuse sweating
nausea and vomiting
drowsiness or coma
flushed skin (due to inadequate blood flow to the skin)
weakness and dizziness
dehydration can also cause irregular heartbeats, seizures, strokes and even death in babies, children and the elderly.