Suspect heat stroke?

Cool first. Call 911.

One person calls 911 now. Everyone else starts cooling the athlete right away, on site, at the same time.
Do not wait for the ambulance to start cooling. Cooling starts before transport.
Start cooling right away, ideally within 10 minutes of collapse. The goal is to lower core body temperature to about 102 degrees Fahrenheit within 30 minutes of collapse.

Recognize heat stroke

Exertional heat stroke is a medical emergency. It happens during exercise, usually in the heat. Warning signs include:

Confusion or disorientation
Irritability or unusual behavior
Staggering or loss of balance
Collapse during or after activity
Loss of consciousness
Very high core body temperature, measured rectally by a trained person

Any change in how an athlete acts during exercise in the heat, such as confusion, irritability, or not making sense, is a warning sign.

When in doubt, treat it as heat stroke. An athlete may still be sweating and still be talking. Start cooling right away. Cooling does not wait for a diagnosis.

Cool first: cold-water immersion

Cold-water immersion, a tub of ice water, is the fastest way to cool an athlete with heat stroke. Do it on site, before transport.

Get the athlete into a tub of ice water. Lift together. Cover the whole body up to the neck, or as much of the body as the tub allows.
Support the head. One person keeps the head and airway above the water, holding the athlete under the armpits with a towel or sheet wrapped across the chest.
Stir the water the whole time. Keep adding ice so the water stays ice cold. Lay an ice-water towel over the head and neck and keep swapping it.
Keep watching the athlete. Check breathing and responsiveness. Be ready to roll the athlete onto their side if they vomit. If the athlete stops breathing normally, follow the 911 dispatcher and get the automated external defibrillator.
Take the athlete out at about 102 degrees Fahrenheit, only when a trained medical professional is measuring rectal temperature. Then hand off to emergency medical services.

No one can take a rectal temperature?

Do not use a mouth, ear, armpit, or forehead thermometer. They are not accurate after hard exercise in the heat. Keep cooling until emergency medical services or a medical professional takes over, and follow your medical team's plan.

No tub? Use the tarp method or ice-water towels.

Tarp method (taco method): Lay the athlete in the middle of a tarp. Two or three people lift the sides and the foot end, leaving the head out, so the tarp forms a taco shape. Pour in ice and water, and gently rock the tarp back and forth to keep the water moving.
Ice-water towels: Soak towels in ice water and cover as much of the body as possible. Keep swapping in fresh ice-cold towels.

These are backups. They cool more slowly than a tub, so set up a filled tub before every practice. Cold packs and cooling products do not replace cold-water immersion.

Then transport

Cool First. Transport Second.

Cool on site first, then transport. Ambulance crews usually do not carry a cold-water immersion tub, so the athlete stays in the tub until cooled.
Tell the 911 dispatcher and the ambulance crew that an athlete with suspected heat stroke is being cooled on site.
Send someone to the gate or parking lot to meet the ambulance and lead the crew in.
Write down the times: collapse, 911 call, cooling start, cooling stop, and handoff to emergency medical services.
More than one athlete down? Tell 911 how many. Cool every athlete with warning signs. No one waits.

Get ready: an emergency action plan

Every school and team needs a written emergency action plan: who calls 911, who cools, where the tub is, and how the ambulance gets in. Practice it before the season.

Wet bulb globe temperature guide

Wet bulb globe temperature is the preferred measure of heat stress for outdoor sports. It counts temperature, humidity, sun, and wind. The heat index is measured in the shade and can read low in full sun.

Check it on site before every practice and game, and keep checking during activity. Decide ahead of time what changes at each level: rest breaks, equipment, practice length, and when to stop.

Where to find your numbers

Your state high school association's heat policy comes first. Use its chart. Some states require it.
If your state has no chart, set limits for your region with your medical team, using the National Athletic Trainers' Association heat illness position statement as a guide.
Check the forecast with the National Weather Service heat tools and its wet bulb globe temperature forecast.

This page lists no temperature numbers on purpose. The right numbers depend on your region and your state's rules.

Learn more

Train your coaches and staff to recognize heat stroke and run cold-water immersion with the Ice Athletes heat safety certification.

See the Ice Athletes certification

From National Stay Cool Day

Heat Stroke Help is a free page from National Stay Cool Day, a national day for heat safety in school sports. National Stay Cool Day is April 8, 2027, starting at 2:00 PM Eastern / 11:00 AM Pacific.

Questions

What is exertional heat stroke?

Exertional heat stroke is a medical emergency in which the body overheats during exercise. It is defined by a core body temperature above 105 degrees Fahrenheit, measured rectally, together with changes in brain function such as confusion, irritability, staggering, or collapse. Treat it right away with cold-water immersion.

Do we call 911 first or start cooling first?

Both at once. One person calls 911 while everyone else starts cooling the athlete on site. Cool first, transport second.

What if we do not have a tub?

Use the tarp method: lay the athlete on a tarp, lift the sides to form a taco shape, pour in ice and water, and rock it gently. Or cover the body with ice-water towels and keep swapping them. Both cool more slowly than a tub, so set up a filled tub before every practice.

When do you stop cooling?

When a trained medical professional measures a rectal temperature of about 102 degrees Fahrenheit. If no one can take a rectal temperature, keep cooling until emergency medical services or a medical professional takes over.

Can I check temperature with an ear, mouth, or forehead thermometer?

No. After hard exercise in the heat, only a rectal temperature is accurate. Other thermometers can miss heat stroke. Go by the warning signs and start cooling.

The athlete is still sweating and talking. Can it still be heat stroke?

Yes. An athlete with heat stroke may still be sweating and still be talking. When in doubt, treat it as heat stroke and start cooling right away.

Who offers this page?

National Stay Cool Day offers this page as a free educational resource. It is reviewed by the Player Safety Council. It has no ads, sponsors, or tracking.