Health Library

Our bodies create a lot of heat. Normally, they’re cooled through sweating and by heat radiating through the skin.

But in very hot weather, high humidity, and other conditions, this natural cooling system may begin to fail, letting heat in the body build to dangerous levels. This can cause heat illness, such as heat cramps, heat exhaustion, or heatstroke.

What Are Heat Cramps?

Heat cramps are painful muscle cramps in the legs, arms, or belly that can happen during or after vigorous exercise in extreme heat. Sweating during the intense physical activity causes the body to lose salts and fluids. This low level of salts likely is what makes the muscles cramp.

Kids are particularly at risk for heat cramps when they aren’t drinking enough fluids. Although they’re painful, heat cramps usually get better when kids drink fluids and get rest.

Cramps can be the first sign of more serious heat illness, though, so they should be treated right away to help avoid any problems.

What to Do:

A cool place, rest, and fluids should help a child feel better. Give water or fluids that contain salt and sugar, such as sports drinks. Gently stretching and massaging cramped muscles also may help. Someone with heat cramps should take it easy for a few hours, even after they feel better.

If cramps don’t get better within an hour, or someone with heat cramps has a history of heart problems or is on a low-sodium diet, they should get medical help.

What Is Heat Exhaustion?

Heat exhaustion is a more severe heat illness that can happen when someone in a hot climate or environment hasn’t been drinking enough liquids. Symptoms can include:

• increased thirst
• weakness
• dizziness or fainting
• muscle cramps
• nausea and/or vomiting
• irritability
• headache
• heavy sweating
• cool, clammy skin
• a raised body temperature, but less than 104°F (40°C)

What to Do:

• Bring your child to a cooler place indoors, an air-conditioned car, or shady area.
• Remove your child’s excess clothing.
• Encourage your child to drink water or cool fluids containing salt and sugar, such as sports drinks.
• Put a cool, wet cloth or cool water on your child’s skin.
• Call your doctor for advice. A child who is too exhausted or ill to drink or who doesn’t feel better within an hour might need to get intravenous (IV) fluids.

If left untreated, heat exhaustion can develop into heatstroke, a much more serious illness.

What Is Heatstroke?

The most severe form of heat illness is heatstroke. Heatstroke is a life-threatening medical emergency.

In heatstroke, the body cannot regulate its own temperature. Body temperature can soar to 106°F (41.1°C) or even higher, and can lead to brain damage or even death if it isn’t treated right away. Quick medical care is needed to bring the body temperature under control.

Kids are at risk for heatstroke if they overdress or do intense physical activity in hot weather without drinking enough liquids.

Heatstroke also can happen when a child is left in, or gets trapped in, a car on a hot day. When the outside temperature is 93°F (33.9°C), the temperature inside a car can reach 125°F (51.7°C) in just 20 minutes, quickly raising body temperature to dangerous levels.

What to Do:

Call for emergency medical help if your child has been outside in extreme temperatures or another hot environment and shows one or more of these symptoms of heatstroke:

• severe headache
• weakness, dizziness
• confusion
• nausea
• rapid breathing and heartbeat
• loss of consciousness
• seizure
• no sweating
• flushed, hot, dry skin
• temperature of 104°F (40°C) or higher

While waiting for help:

• Get your child indoors or into the shade.
• Undress your child and sponge or douse them with cool water.
• Do not give fluids unless your child is awake, alert, and acting normally.

How Can We Prevent Heat Illness?

To help protect kids from heat illness:

• Teach kids to always drink plenty of liquids before and during activity in hot, sunny weather — even if they’re not thirsty.
• Kids should wear light-colored, loose clothing on hot days and use sunscreen when outdoors.
• In hot or humid weather, schedule outdoor activities during the cooler parts of the day in the early morning or evening.
• Teach kids to come indoors, rest, and hydrate right away whenever they feel overheated.