Heat Stress: Warning Signs

Even severe heat stress can appear suddenly, so learn the warning signs and how to treat them.

Mild: heat stress

Core body temperature stays at 98.6°F (37°C). It isn't dangerous unless the symptoms aren't treated. Signs and symptoms include:

  • Sweating a lot
  • Having painful spasms in your muscles during activity or hours afterward (heat cramps)
  • Developing tiny red bumps on skin and a prickling sensation (prickly heat)
  • Feeling irritable or weak

Treatment: Get medical advice and do the following:

  • Rest in a cool, shady area.
  • Drink water or a sport drink.

Moderate: heat exhaustion

Core body temperature may rise up to 101°F (38.3°C). It should be treated right away. Signs and symptoms include:

  • Sweating a lot
  • Cold, moist, pale or flushed skin
  • Feeling very weak or tired
  • Headache, nausea, loss of appetite
  • Feeling dizzy or giddy
  • Rapid or weak pulse

Treatment: Get medical treatment urgently! You may be told to:

  • Rest in a cool, shady area.
  • Drink water or a sport drink. In some cases, a medical professional must administer fluids.
  • Take salt (in some cases).
  • Use cool compresses on the forehead, around the neck, and under armpits.
  • Blow air onto your skin with fans.

Severe: heat stroke

This is a serious, life-threatening medical emergency. Core body temperature can rise to 105°F (40.5°C) or more. If not treated right away, heat stroke can lead to permanent brain damage and even death. Signs and symptoms include:

  • Hot, dry skin that looks red, mottled, or bluish
  • Deep, fast breathing
  • Headache or nausea
  • Rapid, weak, or irregular pulse
  • Feeling dizzy, confused, or delirious
  • Fainting
  • Convulsions

Treatment: Someone should call for emergency help right away. While waiting for emergency help, the affected person should:

  • Rest in a cool, shady area.
  • Have clothing soaked with cool water. Or, remove outer clothing and be wrapped with a sheet soaked in cool water. Place the person in water in a tub or children's swimming pool if available.
  • Be blown with fans.
  • Drink water or a sport drink. (Do not try to give a drink to someone who is unconscious.)