Heatstroke occurs when the body is not able to control its own temperature and body temperature keeps rising. Symptoms of heatstroke include mental changes (such as confusion, delirium, or unconsciousness) and skin that is red, hot, and dry, even under the armpits. Heatstroke is life-threatening and needs emergency medical treatment.

Symptoms of rapidly progressing heatstroke include:

• Passing out (unconsciousness) for longer than a few seconds.
• Seizure s.
• Moderate to severe difficulty breathing .
• A rectal temperature over 104 F (40 C) after exposure to a hot environment.
• Confusion, severe restlessness, or anxiety.
• A fast heart rate.
• Skin that may be red, hot, and dry, even in the armpits.
• Sweating that may be heavy or may have stopped.
• Severe vomiting and diarrhea.

Giving emergency first aid

Heatstroke is a medical emergency. Even with immediate treatment, it can be life-threatening or result in serious, long-term problems. After calling 911 or other emergency medical services, follow these first aid steps.

• Cool the body.
  • Move the person into a cool place, out of direct sunlight.
  • Remove the person's unnecessary clothing and place the person on their side to expose as much skin surface to the air as possible.
  • Cool the person's entire body in a cold water or ice bath or by sponging or spraying cold water, and fan the person to help lower the person's body temperature.
  • Apply ice packs over as much of the body as you can. Place them on the neck, under the arms, and in the groin area.
• Check the person's rectal temperature, which is the most accurate in this medical emergency. Try to reduce it to 102 °F (39 °C) or lower as soon as possible. The longer the body is at a high temperature, the more likely that serious problems will develop. Temperatures taken by mouth or in the ear are not accurate in this emergency situation.
• Watch for symptoms of rapidly progressing heatstroke. These include seizure, unconsciousness for longer than a few seconds, and moderate to severe difficulty breathing.
• Start CPR if needed. If the person is unconscious or doesn't respond to your voice or touch, be ready to start CPR.
• Give the person fluids for hydration. If the person is awake and alert enough to swallow, give them plenty of cool water to drink. You may have to help. Make sure the person is sitting up enough so that they don't choke. Most people with heatstroke have an altered level of consciousness and cannot safely be given fluids to drink.

Do not give aspirin, acetaminophen, or nonsteroidal anti-inflammatory drugs (NSAIDS) to reduce a high body temperature that can occur with heatstroke. These medicines may cause problems because of the body's response to heatstroke.