Dehydration

Dehydration occurs when more fluids are lost than are consumed. By definition, dehydration means that the amount of body water is below optimal. As little as a 2 percent drop in body water results in a measurable reduction in athletic performance. Common risks for dehydration include the following:

• Vomiting
• Diarrhea
• Inadequate fluid replacement
• Induced high sweat rates (as in saunas)
• Laxatives
• Diuretics (and substances with a diuretic effect, such as high intakes of caffeine)
• Dieting
• Febrile illness

Ideally, dehydration avoidance is the best policy. The only way to avoid dehydration is to rightly assume there is a constant output of fluids that must be dealt with by having an equally constant input of fluids. It is important for athletes to recognize the signs of dehydration. Thirst is an obvious sign, but athletes should learn to monitor urine output for volume and color. Both low urine output and dark urine color are signs of dehydration that may precede the sensation of thirst.

Some athletes dehydrate themselves to try to look better or to make a competitive weight classification, or they fail to consume fluids even when they are readily available to them (referred to as voluntary dehydration); other athletes become dehydrated as a result of heavy training, particularly in hot and humid environments, when adequate fluid consumption is difficult (referred to as involuntary dehydration). Regardless of the cause, athletes can be certain that dehydration will result in negative performance outcomes and reduced mental function.