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Heat Exposure and Reactions


  • 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 fever higher than 105° F (40.5° C). More than 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.
  • Exertion. During hot weather, hard work or sports can cause heat production to exceed heat loss.
  • Dehydration. Sweating during hot weather can cause sweat loss to exceed fluid intake. Poor hydration then interferes with sweating and increases the risk of heat reactions.
  • Heat waves. The first heat wave of the summer can cause heat problems. It takes 8 to 10 days for you to become used to high summer temperatures. This sudden change in temperature can also happen on vacations.
  • 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 the main cause of heat stroke in the elderly.
  • Health and risk factors. Babies are less able to sweat when hot. Obese children also have a decreased ability to give off heat.

When To Call

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 higher than 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 higher than 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
  • Fever in baby less than 12 weeks old. 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

Contact 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 (less than 104° F or 40.0° C) from heat exposure
  • Prevention of heat reactions

Care Advice

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. For young children, give Pedialyte or other rehydration fluids. You can also give half-strength apple juice or half-strength Gatorade.
  • 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.
  • Younger children (1-5). Start with 4-8 ounces (120-240 mL). Then give 2-4 ounces (60-120 mL) every 15 minutes for the next 1-2 hours or until feels better.
  • 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.

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.

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.

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.

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. Cool means less than body temperature. Reason: brings down the temperature faster.
  • No Meds: fever medicines are of no value for this type of fever.

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.

Rest - Lie Down:

  • Rest in a cool place with a fan until feeling better.

Prevention Of Heat Reactions:

  • Drink more water. When working or exercising in hot weather, 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 liquid for replacing lost sweat. Very little salt is lost.
  • Sports drinks. 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.
  • Take water breaks. Do this every 15 minutes in the shade. Drink some water even if you're not thirsty. Thirst can be delayed until a person is almost dehydrated.
  • Avoid salt tablets. They slow down stomach emptying and delay the absorption of fluids.
  • Dress cool. Wear a single layer of lightweight clothing. Change it if it becomes wet with sweat. 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.
  • Exercise smart. 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 higher than 82°F (28°C). Also, this is very important if the humidity is high.
  • Stay cool. 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.
  • Limit hot tub time. 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. Age limit: children less than 3 years old should not use hot tubs. Reason: poor heat tolerance and increased risk for rapid onset of high body temperature.

Call Your Doctor If:

  • Vomiting keeps your child from drinking
  • Signs of dehydration occur
  • Muscle cramps last more than 4 hours
  • Fever goes higher than 104°F (40.0°C)
  • Fever lasts more than 2 hours
  • You think your child needs to be seen
  • Your child becomes worse



FIRST AID Advice - Heat Exhaustion

  • Move the person to a cool shady area. If possible, move them into an air-conditioned place.
  • Have the person lie down. Elevate the feet.
  • Undress the person (except for underwear), so the body surface can give off heat.
  • Sponge the entire body surface continuously with cool water. Fan the person to increase evaporation.
  • Give as much cold water or sports drink (e.g., Gatorade, Powerade) as the person can tolerate. An adult or teen with heat exhaustion should drink 2-3 cups (480-720 mL) of liquids right away to replace what was lost. Then the adult or teen should drink approximately 1 cup (240 mL) every 15 minutes for the next 1-2 hours.

Source: Self Care Decisions, LLC
Used with Permission from Schmitt Pediatric Guidelines LLC.

Barton Schmitt MD, FAAP
Disclaimer: this health information is for educational purposes only. You, the reader, assume full responsibility for how you choose to use it.
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