Dehydration is a condition that occurs when the body loses more fluid than it takes in.  It can range from a mild form, which is easily treated by drinking more fluids, to severe and life-threatening conditions if left untreated. While the risk of dehydration is greater for the very young and the elderly, young people participating in sports can also experience dehydration.  This occurs because children produce more heat, perspire less, and are less likely to drink sufficient fluids while exercising.

The most common causes of dehydration are fever, frequent vomiting, intense diarrhea, or excessive sweating.  However, playing sports may cause athletes to become dehydrated if they don't drink enough fluids.  This is especially true if the individual rarely plays sports, is overweight or obese, is recovering from a recent illness involving vomiting or diarrhea, or has a history of heat-related illness in the past. 

Playing a sport which requires protective equipment (football, lacrosse, etc.) increases the risk of dehydration especially when playing and/or practicing in hot, humid weather. To reduce the risk of dehydration, athletes participating in sports, like football, which normally begin in late summer should try to pace their activities and gradually increase the amount of activity and protective gear over the course of several days.  Acclimation to the heat may take as long as two weeks. 

Symptoms of mild to moderate dehydration: 

• Dry, sticky mouth
• Irritability
• Sleepiness or tiredness
• Thirst
• Decreased urinary output
• Headache
• Dizziness or lightheadedness
• Muscle weakness
• Few or no tears when crying

For the health and safety of young athletes, the American Academy of Pediatrics has issued recommendations for coaches to follow during hot and humid weather:

Reduce the intensity of physical activity lasting more than 15 minutes

Require that young athletes drink plenty of fluids before practice and during regular beverage breaks - even if they aren't thirsty

Limit clothing to a single layer of light-colored, lightweight material.

Mild or moderate dehydration can be treated by increasing fluid intake (drinking water or an electrolyte liquid, like Gatorade).  When dehydration is severe, it can lead to serious heat-related illnesses including heat cramps, heat exhaustion, and heat stroke and requires medical treatment.