Heat Exhaustion

What is heat exhaustion?

Heat exhaustion, also called heat prostration, is the most common heat-related problem. It often results from heavy physical activity in hot conditions, and not drinking enough liquids. Normally, the body has a cooling system that is controlled by the brain to make the organs work properly. The cooling system adjusts and lowers the temperature by producing sweat. With heat exhaustion, the body's cooling system is not working well and results in an increased body temperature. Normal body temperature for an adult is generally 37 degrees Celsius, or 98.6 degrees Fahrenheit. With heat exhaustion, body temperature is usually between 37 to 40 degrees Celsius (98.6 to 104 degrees Fahrenheit). Heat exhaustion may damage cells and cause dehydration (loss of too much water and mineral salts). As the body temperature increases and affects your brain, heat exhaustion can lead to heatstroke.

What are the causes of heat exhaustion?

The following are possible causes and conditions that may increase your chance of having heat exhaustion:

• Extremes of age: Old people and very young children have a hard time adjusting quickly to high temperatures and weather changes.
  
  
• High temperatures: These usually occur during heat waves in spring or early summer. Being closed in a hot environment, such as in a desert, a cabin, or an enclosed attic. Working in machinery or power plants, such as boiler rooms. The lack of an air conditioning system during high temperatures may further increase the chance of heat exhaustion.
  
  
• Illegal drugs and drinking alcohol: Use of illegal (street) drugs, such as cocaine, heroin, or amphetamines, may damage your cooling system. Alcohol is found in beer, wine, liquor (vodka or whiskey), and other adult drinks.
  
  
• Medical conditions: Malnutrition (poor nutrition), diabetes, kidney or thyroid disease, heart failure or liver problems. Previous history of a heat-related problem or skin disease may also increase your chance of developing heat exhaustion.
  
  
• Medicines: Certain medicines used for treating pain, allergies, depression, heart problems, or tumors.
  
  
• Obesity: Weighing more than what your caregiver recommends.
  
  
• Too much exercise or physical activity: Sweating a lot can make your body lose too much salt and water. Hard exercise which lasts a long time occurring during sporting events, such as marathons, triathlons, and bicycling. Those doing heavy physical training and manual labor in a hot environment may also get heat exhaustion. These include military recruits, firefighters, police officers, construction workers, or miners.

What are the signs and symptoms of heat exhaustion?

Signs and symptoms usually appear when water and electrolytes in your body drop too low or too fast. Because of this, you may be unable to continue exercising or doing physical activity in the heat. You may also have any of the following:

• Body temperature between 37 to 40 degrees Celsius (98.6 to 104 degrees Fahrenheit).
  
  
• Headache, dizziness, or body weakness.
  
  
• Irregular or fast breathing, fast or pounding heartbeat, and low blood pressure.
  
  
• Muscle weakness and twitching, or a feeling of pins and needles on the skin.
  
  
• Nausea (upset stomach), vomiting (throwing up), or abdominal (stomach) cramps.
  
  
• Too much sweating.

How is heat exhaustion diagnosed?

Your caregiver will need to take your body temperature through the mouth, armpit, or anus (rear end). You may also need any of the following tests:

• Heart monitor: This test is also called an EKG or ECG. Sticky pads are placed on your skin to record your heart's electrical activity. An EKG gives information about how your heart is working. Lie as still as possible during the test.
  
  
• Blood and urine tests: Samples of your blood and urine are collected. These are sent to a lab for tests to check the levels of your salts and minerals.
  
  
• Blood gases: This is also called an arterial blood gas, or ABG. Blood is taken from an artery (blood vessel) in your wrist, arm, or groin. Your blood is tested for the amount of oxygen and carbon dioxide in it. The results can tell caregivers how well your lungs are working.

How is heat exhaustion treated?

Heat exhaustion needs to be treated as soon as possible to prevent further problems. Caregivers may suggest that you rest in bed and stay in a cool or well-ventilated room. You may also need any of the following:

• Cooling sheets: Different types of cooling sheets and materials may be used to quickly decrease your body temperature. You may be wrapped with ice-soaked blankets to lower your temperature.
  
  
• Fluids:
  
  
  • Intravenous fluids: These are liquid solutions that contain water, mineral salts, sugars, and proteins. These may be given through your vein (IV) to increase your fluid volume.
    
    
  • Oral rehydrating solutions: Caregivers may give you oral rehydration solution (ORS) to drink. An ORS has the right amounts of water, salts, and sugar your body needs to replace body fluids. This may help prevent dehydration.
  
  
• Oxygen: You may need extra oxygen if your blood oxygen level is lower than it should be. You may get oxygen through a mask placed over your nose and mouth or through small tubes placed in your nostrils. Ask your caregiver before you take off the mask or oxygen tubing.

What should I do if I think someone has heat exhaustion?

• Move the person with heat exhaustion to a cool, shaded area and turn him on his side.
  
  
• Check if the person is breathing or has a pulse. Start rescue breathing and CPR (basic life support) if needed. Have someone call 911 immediately for medical assistance.
  
  
• If the person is awake and cool water is available, drench him in cool water. You may also wrap him with cool water-soaked sheets. This may drop his body temperature rapidly. Give him cool liquids if he can drink them.
  
  
• Remove his clothing and start fanning him, or spraying lukewarm water on his body.
  
  
• Apply ice packs on the neck, armpits, and groin (area where the trunk and legs meet).
  
  
• Do not give fever medicines, such as acetaminophen and ibuprofen, to lower the body temperature.

How can heat exhaustion be prevented?

You can do the following when exercising or in a place with a very high temperature:

• Drink lots of liquids, such as water, fruit juices, or energy drinks, even if you do not feel thirsty. Avoid drinking alcoholic drinks, such as beer, wine, liquor (vodka and whiskey), and other adult drinks.
  
  
• Eat salty foods, such as celery, salted crackers, and salted pretzels.
  
  
• Limit your activities or strenuous exercises during the hottest time of the day. The hottest time of the day is usually late morning through early afternoon. Athletes should plan to arrive in a location 3 to 4 days before an outdoor event to adjust to the heat. .
  
  
• Never leave children alone inside cars, especially during hot weather.
  
  
• Use air conditioners or fans, and have enough proper ventilation. If there is no air conditioning available, keep your windows open so that air may enter the rooms.
  
  
• Wear lightweight, loose, and light-colored clothing. Protect your head and neck with a hat or umbrella when you are outdoors.
  
  
• When planning your daily activities, check out the weather forecast first, especially if you need to work outdoors.

Where can I find more information?

Having heat exhaustion may be hard for you and your family. Contact the following for more information:

• American Academy of Family Physicians
  11400 Tomahawk Creek Parkway
  Leawood , KS 66211-2680
  Phone: 1- 913 - 906-6000
  Phone: 1- 800 - 274-2237
  Web Address: http://www.aafp.org
  

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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