Children's Hospital Colorado

Heat Exposure and Reactions

Urgent or Emergency Care?

If you believe your child needs immediate attention and you have concerns for a life-threatening emergency, call 911. Not sure what counts as urgent and what's an emergency when your child is sick or injured? When it can't wait, know where to take your kids.

Help Me Decide

  • 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

Types of Heat Reactions

  • There are 3 main reactions to hot temperatures and heat waves.
  • Heatstroke or Sunstroke (Serious). 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 of Heat Reactions

  • 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.

Call 911 Now

  • Hard to wake up or can't wake up
  • Acts or talks confused
  • Seizure occurred
  • Signs of shock (very weak or gray, cool skin)
  • Fever over 105° F (40.5° C)
  • You think your child has a life-threatening emergency

Go to ER Now

  • Passed out (fainted) or too weak to stand
  • Fever over 104° F (40° C)
  • Can't walk or can barely walk (not steady, needs support)

Call Doctor or Seek Care Now

  • Age less than 12 weeks old and not acting normal after heat exposure
  • Age less than 12 weeks old with fever. Caution: do NOT give your baby any fever medicine before being seen.
  • Vomiting keeps from drinking fluids
  • Dehydration suspected. No urine in more than 8 hours, dark urine, very dry mouth and no tears.
  • Fever or dizziness still there after drinking fluids for more than 2 hours
  • Your child looks or acts very sick
  • You think your child needs to be seen, and the problem is urgent

Call Doctor Within 24 Hours

  • You think your child needs to be seen, but the problem is not urgent

Self Care at Home

  • 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

Care Advice for Heat Exposure

  1. Drink Lots of Fluids:
    • All the symptoms of heat reactions respond to fluid replacement.
    • Type of Fluid. Give your child as much cold water as he will drink. Do this until he feels better.
    • If you have a sports drink (such as Gatorade), give it instead. Sports drinks contain water, salt and sugar.
    • How Much (Teens). Start with 3 cups (24 ounces or 720 mL). Then give 1 cup (240 mL) every 15 minutes for the next 1-2 hours.
    • Preteens (6-12). Start with 2 cups (16 ounces or 480 mL). Then give 6 ounces (180 mL) every 15 minutes for the next 1-2 hours.
    • Urine Color. The urine color can tell you if drinking enough fluids. Dark yellow urine means mild dehydration. Clear or light yellow urine means your child is drinking enough fluids.
  2. Heat Cramps - What You Should Know:
    • Heat cramps are the most common reaction to heat exposure. They are never serious. Sometimes, they can be an 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.
    • Heat cramps should clear in 1 to 2 hours after lost fluids are replaced.
  3. Heat Exhaustion:
    • Put the child in a cool place. Have him lie down with the feet elevated.
    • Undress him (except for underwear) so the body surface can give off heat.
    • Sponge the entire body surface constantly with cool water. Make the water as cold as tolerated without causing shivering.
    • Weakness should clear in 2 to 3 hours after lost fluids are replaced.
  4. 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.
  5. 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.
    • Fluids: First, have your child drink some liquids.
    • Cool Bath: Second, take a cool bath or shower for 5 minutes. Reason: Brings down the temperature faster.
    • No Meds: Fever medicines are of no value for this type of fever.
  6. Salty 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.
  7. Rest - Lie Down:
    • Rest in a cool place with a fan until feeling better.
  8. 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.
  9. 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.
  10. 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
    • You think your child needs to be seen
    • Your child becomes worse


The information contained in these topics is not intended nor implied to 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.

Always seek the advice of your physician or other qualified healthcare provider before starting any new treatment or discontinuing an existing treatment. Talk with your healthcare provider about any questions you may have regarding a medical condition. Nothing contained in these topics is intended to be used for medical diagnosis or treatment.

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  • Supplement - The information and materials presented here in Pediatric HouseCalls Symptom Checker are meant to supplement the information that you obtain from your physician. If there is a disagreement between the information presented herein and what your physician has told you -- it is more likely that your physician is correct. He or she has the benefit of knowing your child's medical problems.
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    • You can have a conversation with your child's doctor.
    • Your child's doctor can perform a physical examination and any necessary tests.
    • Your child could have an underlying medical problem that requires a physician to detect.
    • If your child is taking medications, they could influence how he experiences various symptoms.

If you think that your child is having a medical emergency, call 911 or the number for the local emergency ambulance service NOW!

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