Heatstroke and Dehydration: Prevention and Treatment

Newcomers to Phoenix driving around the big city — with its tall buildings and paved streets — may find it easy to forget this metropolis really is a desert, complete with all the hazards of hot and arid climates.

Forgetting that this is a desert puts people in peril, according to Glendale family physician Karla Birkholz, MD, because heatstroke and dehydration can be lethal. The good news is that with just a small amount of forethought and planning, these threats are relatively easy to prevent. And, as always, prevention is much better than having to treat heatstroke or dehydration.

Keys to prevention are water and sun protection, Dr. Birkholz said.


More than 75 percent of our body weight is water. Water is essential to our metabolism, the way our bodies function. It's especially dangerous for infants and young children, the elderly and people with chronic medical conditions to become dehydrated.

When people are active outdoors in the heat, Dr. Birkholz advised that adults need 16 to 20 ounces (two to three cups) of fluids before beginning activity, as well as an additional 6 to 10 ounces every 10 to 20 minutes during activity. Make sure your fluids include electrolyte or sports drinks, alternating with water, if you're active outside more than one or two hours.

Fluid needs don't stop when activity is over — people should consume 24 ounces of fluid (three cups) within the first two hours after outdoor activity.

Children need 4 to 8 ounces of fluid (half a cup to a cup) before beginning outdoor activities and every 20 minutes while they are outside. Once kids return from outside play or activity, they also need to consume 24 ounces of fluids within the first two hours after they stopped their activities.

Did you know? One adult-size gulp of fluid equals one ounce of fluid, and one child-size gulp of fluid equals one-half ounce of fluid.


Dehydration occurs when the amount of water leaving the body is greater than the amount taken in.

We lose water breathing, sweating, eliminating waste material or through illness — vomiting and diarrhea or diabetes, Dr. Birkholz said. Serious burns also drain water from the body.

Progressive signs and symptoms of dehydration are:

  • Thirst
  • Decreased urine output
  • Dry mouth
  • Reduced sweat
  • Muscle cramps
  • Nausea and vomiting
  • Heart Palpitations
  • Dizziness
  • Weakness
  • Confusion
  • Coma
  • Organ Failure
  • Death

Treating Dehydration

It is vitally important to replace lost fluid as rapidly and efficiently as possible, Dr. Birkholz emphasized. If the patient is conscious, offer water, clear broth, Popsicles, Jell-O or a sports drink like Gatorade.

If the patient is vomiting, has diarrhea or fever, get the patient to a doctor.

If the patient is confused, lethargic or in a coma, call 9-1-1.

It is especially important to get medical care for children who have passed the stages of being fussy, tired or irritable, when Pedialyte or Gatorade in addition to water can help, Dr. Birkholz said. Call 9-1-1 for children who are experiencing dry mouth, sunken eyes and increased heart and breathing rates, or who are listless, lethargic, too weak to cry or drink and have weak pulse rates or mottled skin.

Heat Illness

Heat illness is caused by exposure to environmental heat that raises core body temperatures above 105 degrees F, Dr. Birkholz explained. Heat illnesses range progressively from heat rash, heat cramps and heat exhaustion to heatstroke.

Dr. Birkholz recommends preventing heat illness with adequate hydration and protective clothing. Wear a broad-brimmed sun hat and light colored, loose fitting clothing. Long sleeves and long pants can protect you more than sleeveless shirts and shorts. Wear sun block with an SPF factor of at least 30, she advised.

Be on the lookout for signs of trouble. Symptoms of heat illness include:

  • Rapid pulse
  • Muscle cramps
  • Extreme fatigue
  • Flushed cheeks
  • Nausea
  • No sweat
  • Confusion
  • Unconsciousness

Treating Heat Illness

Get the patient out of the sun, into shade or any cool spot, if at all possible, Dr. Birkholz said. If a spray bottle is available, spray the person down and use any kind of fan to move the air around the patient.

If the person can swallow, encourage them to drink water or Gatorade, or suck on ice chips. Cool, wet towels applied to the head, neck, under arms or groin area can help.

If sweat stops, confusion sets in or the patient becomes unconscious, don't delay: Call 9-1-1 immediately.

Karla Birkholz, MD, is the medical director of Wellness Elements, a wellness center for John C. Lincoln Physician Network, and can be contacted at 623-298-3015.

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