Dehydration means excess loss of water from the body. Dehydration is one of the most common after exercises, having loose stools or sever vomiting. It should be treated with excess of ingestion of fluids. Dehydration sgould be treated, other wise it may leads to shock.

Under normal conditions, we all lose some body water every day in our sweat, tears, urine, and stools. Water also evaporates from our skin and leaves the body as vapor when we breathe. We usually replace this body fluid and the salts it contains with the water and salts in our regular diet.
Sometimes, however, children lose abnormally large amounts of water and salts through fever (more water evaporates from the body when body temperature is increased), diarrhea, vomiting, or long periods of exercise with excessive sweating. Some illnesses might also prevent children from taking fluids by mouth. If they're unable to adequately replace the fluid that's been lost, kids can become dehydrated.

Recognizing Dehydration:

If your child has fever, diarrhea, or vomiting, or is sweating a lot on a hot day or during intense physical activity, you should watch for signs of dehydration, which can include:

• Dry or sticky mouth.
• Few or no tears when crying.
• Eyes that looks sunken into the head.
• Soft spot (fontanel) on top of baby's head that looks sunken.
• Lack of urine or wet diapers for 6 to 8 hours in an infant (or only a very small amount of dark yellow urine).
• Lack of urine for 12 hours in an older child (or only a very small amount of dark yellow urine).
• Dry, cool skin.
• Lethargy or irritability.
• Fatigue or dizziness in an older child.

Preventing Dehydration:

The best way to prevent dehydration is to make sure kids gets plenty of fluids, whether they're sick or just physically active. In other words, you need to make sure that they're consuming more fluids than they're losing (from vomiting, diarrhea, or sweating).
The way you should keep a child adequately hydrated will differ depending on the circumstances. For example, a child with a sore throat may become dehydrated due to difficulty drinking or eating. Easing the pain with acetaminophen or ibuprofen may help. Cold drinks or popsicles can also soothe a burning throat while supplying fluids at the same time.
Infants with blocked noses who have trouble feeding can be helped by flushing their nostrils with saltwater, or saline, nose drops and suctioning out the mucus with a bulb syringe.