Heatstroke occurs when your body temperature rises rapidly and you’re unable to cool down. It can be life threatening by causing damage to your brain and other vital organs. It may be caused by strenuous activity in the heat or by being in a hot place for too long.

Heatstroke can occur without any previous heat-related condition, such as heat exhaustion. Heatstroke signs and symptoms include:

• Fever of 104 F (40 C) or greater
• Changes in mental status or behavior, such as confusion, agitation or slurred speech
• Hot, dry skin or heavy sweating
• Nausea and vomiting
• Flushed skin
• Rapid pulse
• Rapid breathing
• Headache
• Fainting, which may be the first sign in older adults

If you suspect someone is suffering from heatstroke, call 911 or your local emergency number. Then immediately move the person out of the heat and cool him or her by whatever means available, for example:

• Put the person in a cool tub of water or a cool shower
• Spray with a garden hose
• Sponge with cool water
• Fan while misting with cool water
• Place ice packs or cool wet towels on the neck, armpits and groin.
• Cover with cool damp sheets.

Let the person drink cool water or other nonalcoholic beverage without caffeine, if he or she is able.

Begin CPR if the person loses consciousness and shows no signs of circulation, such as breathing, coughing or movement.