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Medical Author:

Charles Patrick Davis, MD, PhD

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

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Medical Editor:

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Taking in an adequate amount of fluid and food (they both often contain adequate electrolytes in a normal diet) is the way most people avoid dehydration. The USDA recommends the following:

"Because normal hydration can be maintained over a wide range of water intakes, the Adequate Intake (AI) for total water was set based on the median total water intake from U.S. survey data (IOM, 2004). The AI for total water intake for young men and women (age 19 to 30 years) is 3.7 L and 2.7 L per day, respectively. In NHANES III (study), fluids (drinking water and beverages) provided 3.0 L (101 fluid ounces; about 13 cups) and 2.2 L (74 fluid ounces;  about 9 cups) per day for men and women age 19 to 30, representing approximately 81 percent of total water intake. Water contained in food provided about 19 percent of total water intake."

The above are estimates; other research bases the amount of fluid intake on weight and provides tables to estimate an individual's fluid intake (see reference 2, MedicineNet's Dehydration article). Dehydration is often preventable even under more stressful conditions such as participation in sports or work on hot days.

Anticipation of the need for increased fluid intake is a key to prevent dehydration.

• Plan ahead and take extra sports drinks that contain electrolytes and water bottles to all outdoor events and work areas where increased sweating, activity, and heat stress will likely increase a person's fluid loss. Encourage athletes and outdoor workers to replace fluids at a rate that equals the loss.
• Avoid exercise and exposure during high heat index (high air temperature with high humidity) days. Listen to weather forecasts for high heat stress days, and plan events that must occur outside during times when temperatures are cooler, usually in the early AM and after sunset..
• Ensure that older people and infants and children have adequate drinking water and fluids containing electrolytes available, and assist them as necessary. Make sure that any incapacitated or impaired person is encouraged to drink and is provided with adequate fluids.
• Avoid alcohol consumption, especially when it is very hot, because alcohol increases water loss and impairs a person's ability to sense early signs associated with dehydration.
• People should wear light-colored and loose-fitting clothing if they must be outdoors when it is hot outside. Carry a personal fan or mister to cool the body so less fluid is lost through sweating.
• Limit the time a person is exposed to hot temperatures. Find air-conditioned or shady areas and allow the body to cool between exposures. Taking someone into a cooled area for even a couple of hours each day will help prevent the cumulative effects of high heat exposure.

Clemson University has developed recommendations for fluid intake when a person needs to endure outside activity in hot weather:

Drink the following amounts of fluids when exercising rigorously or in very hot weather:

• Two cups during the two hours before exercising; 1 to 2 cups within 15 minutes of the activity
• One half to 1 cup every 15 to 20 minutes during exercise (One medium mouthful of fluid equals about 1 ounce, and 8 ounces equals 1 cup.)
• Drink 3 cups for each pound of body weight lost.

Dehydration can be prevented by making the decision to take actions to stay well hydrated.

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