Health Library

Heat Stress: Warning Signs

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

Mild: Heat Cramps

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, dizzy, 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! 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:

• Sweating stops

• 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.

• Be blown with fans.

• Drink water or a sport drink. (Do not try to give a drink to someone who is unconscious.)