Heat Exposure and Reactions  

This Care Guide Covers:

  • Symptoms after being in high temperatures (such as heat waves)
  • Symptoms after hard work or sports during hot weather
  • Heat cramps, heat exhaustion and heatstroke are covered
  • Prevention of heat exposure symptoms also covered

If not, see these topics
  • Age less than 3 months and fever. See FEVER.
  • Fever and NO exposure to high temperatures. See FEVER.
View First Aid Advice
  • First Aid For Heatstroke Or Sunstroke
  • First Aid For Heat Exhaustion

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First Aid - Heat Exhaustion
First Aid - Heat Exhaustion

When to Call Your Doctor

Call 911 Now (your child may need an ambulance) If
  • Hard to wake up or can't wake up
  • Acts or talks confused
  • Seizure has occurred
  • Signs of shock (very weak or gray, cool skin)
  • Fever more than 105° F (40.5° C)
  • You think your child has a life-threatening emergency
Call Your Doctor Now (night or day) If
  • Your child looks or acts very sick
  • Passed out (fainted) or too weak to stand
  • Age under 12 weeks old and not acting normal after heat exposure
  • Age under 12 weeks old with fever. (Caution: Do NOT give your baby any fever medicine before being seen.)
  • Fever over 104° F (40° C)
  • Can't walk or can barely walk (not steady, needs support)
  • Vomiting keeps from drinking fluids
  • Dehydration suspected. (No urine in over 8 hours, dark urine, very dry mouth and no tears)
  • Fever or dizziness still there after drinking fluids for more than 2 hours
  • You think your child needs to be seen urgently
Call Your Doctor Within 24 Hours (between 9 am and 4 pm) If
  • You think your child needs to be seen, but not urgently
Parent Care at Home If
  • Normal muscle cramps or sore muscles from heat exposure
  • Normal dizziness from heat exposure
  • Normal fever (under 104° F or 40.0° C) from heat exposure
  • Prevention of heat reactions
Causes & Health Information

Types of Heat Reactions

  • There are 3 main reactions to hot temperatures and heat waves.
  • Heatstroke or Sunstroke. Symptoms include hot, flushed skin with high fever over 105° F (40.5° C). A rectal temperature is more accurate than an oral temperature in these cases. 50% of children with heatstroke do not sweat. Heatstroke can cause confusion, coma or shock. Heatstroke is a life-threatening emergency. It has a high death rate if not treated promptly.
  • Heat Exhaustion. Symptoms include pale skin, profuse sweating and nausea. Dizziness, fainting, or weakness can also be signs. Can have a mild fever 100 - 102° F (37.8 - 39° C) for a short time. Most of the time, there is no fever. Most of these symptoms are caused by dehydration from sweating. A person can progress from heat exhaustion to heatstroke. So, all patients with severe symptoms (such as fainting) need to be seen now. Mild symptoms (such as dizziness) can be treated at home with fluids and rest. But, if these don't resolve with treatment, these children also need to be seen.
  • Heat Cramps. Severe muscle cramps in the legs (calf or thigh muscles) and stomach are present. No fever. Tightness or spasms of the hands may occur.
  • After your child drinks fluids and cools down, he or she will feel better. All symptoms should go away in a few hours.

Causes

  • All 3 reactions are caused by exposure to high temperatures often with high humidity.
  • During hot weather, hard work or sports can cause heat production to exceed heat loss.
  • Poor hydration interferes with sweating and increases the risk of heat reactions.
  • Babies are at more risk because they are less able to sweat when hot.
  • A hot humid climate can also add risk if you aren't used to it. This happens on vacations. The first heat wave of the summer can cause similar problems. It takes 8 to 10 days for you to become used to high summer temperatures.
  • Heatstroke is a breakdown in how the body regulates temperature. It usually follows exposure to a very high temperature. Examples are being inside a hot car or in a steam tent. Being indoors without air-conditioning during heat waves is also a risk factor.  
CARE ADVICE FOR HEAT EXPOSURE

  1. Heat Cramps - What You Should Know:
    • Heat cramps are the most common reaction to heat exposure. They are never serious. Sometimes, they can be a early warning sign of heat exhaustion.
    • The cramps occur in the muscles that were working the hardest.
    • Heat cramps can be quite painful.
    • Heat cramps mean that the body needs rest and more liquids and salt.
  2. Dizziness - What You Should Know:
    • Dizziness and weakness can be caused by mild dehydration. This occurs from all the sweating that happens when hot.
    • Dizziness should clear in 1 to 2 hours after the lost fluids are replaced.
    • Mild dehydration can also cause nausea. It should pass after drinking enough fluids.
  3. Fever - What You Should Know:.
    • The body can become overheated from activity when it's hot outdoors. The temperature should come down to normal after drinking fluids and resting. This may take 1 or 2 hours.
    • No Meds: Fever medicines are of no value for this type of fever.
    • Cool Bath: First, have your child drink some liquids. Then, take a cool bath or shower for 5 minutes. Reason: Brings down the temperature faster.
  4. Drink Liquids to Rehydrate:
    • Give a sports-rehydration drink (such as Gatorade), which contains sugar and salt OR
    • Give water with some salty foods (such as potato chips or pretzels).
    • Start with 2 or 3 cups (480-720 ml) for teens.
    • Then give 1 cup (240 ml) every 15 minutes for the next 1-2 hours. (Teens)
    • The urine color can help tell if drinking enough liquids. Dark yellow urine means mild dehydration. Clear or light yellow urine means your child is drinking enough liquids.
  5. Food:
    • After your child has taken 2 or 3 glasses of water, offer some salty foods. Potato chips or pretzels are helpful.
    • Don't give salt tablets. Reason: They slow down the absorption of water and may cause vomiting.
  6. Rest:
    • Rest in a cool place with a fan until feeling better.
  7. Prevention Of Heat Reactions:
    • When working outside, have your child drink large amounts of cool water. This helps to prevent dehydration. For teens, this means at least 8 ounces (240 ml) every 15 to 30 minutes. Water is the ideal solution for replacing lost sweat. Very little salt is lost.
    • Most often, special sports drinks offer no advantage over water. But, they are helpful if working out for longer than an hour. If that is the case, replace 1 water drink per hour with a sports drink.
    • Have your child take water breaks every 15 minutes in the shade. Have him drink some water even if he's not thirsty. Thirst can be delayed until a person is almost dehydrated.
    • Do not use salt tablets. They slow down stomach emptying and delay the absorption of fluids.
    • Have your child wear a single layer of lightweight clothing. Change it if it becomes wet with sweat.
    • Physical activity in hot weather should be increased slowly.
    • Sports coaches suggest that exercise sessions be shortened and made easier when it's hot. This is usually when the temperature is over 82°F (28°C). Also, this is very important if the humidity is high.
    • Protect babies with fevers from heatstroke by not bundling them in blankets. Also, do not dress them in too many clothes. Children usually need the same number of clothing layers as adults.
    • During heat waves, spend as much time as possible inside with air-conditioning. Electric fans also help. Slow down. It takes at least a week to get used to hot summer temperatures.
  8. Prevention - Hot Tubs:
    • Age limit: Do not use hot tubs in children less than 3 years old.
    • Reason: Poor heat tolerance and increased risk for rapid onset of high body temperature.
    • When using a hot tub, limit use to 15 minutes. Use a "buddy" system in case a heat reaction suddenly occurs.
    • Do not use a hot tub if your child has a fever. Also, do not use them right after hard work or sports. The body needs to get rid of heat.
  9. Call Your Doctor If:
    • Vomiting keeps from drinking
    • Signs of dehydration occur
    • Muscle cramps last more than 4 hours
    • Fever goes above 104°F (40.0°C)
    • Fever lasts more than 2 hours
    • Your child becomes worse

And remember, contact your doctor if your child develops any of the "Call Your Doctor" symptoms.
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Disclaimer: This information is not intended be a substitute for professional medical advice. It is provided for educational purposes only. You assume full responsibility for how you choose to use this information.


Author and Senior Reviewer: Barton D. Schmitt, M.D.

Last Reviewed: 9/1/2012

Last Revised: 1/13/2013

Content Set: Child Symptom Checker

Copyright 1994-2012 Barton D. Schmitt, M.D.