About Heat Stroke: Symptoms and Complications

The symptoms of heat stroke are quite different from those of heat exhaustion.

Symptoms of heat exhaustion:

  • moderately high core temperature - up to 102°F (39°C) (Core temperature is the temperature of the body's internal organs. It's best measured with a rectal thermometer.)
  • cool, pale, clammy skin
  • headache
  • nausea
  • fatigue
  • dizziness or lightheadedness
  • possible fainting, but can be revived

A person suffering from heat exhaustion will usually be sweating profusely in an attempt to lose excess heat. Someone with heat stroke has stopped sweating, due to a failure in his or her heat control system.

Symptoms of heat stroke:

  • extremely high core temperature - up to 106°F (41°C)
  • hot, red, dry skin
  • rapid pulse
  • rapid, shallow breathing
  • headache
  • confusion, strange behaviour
  • possible loss of consciousness

High core temperatures damage the internal organs, especially the brain. The fluid loss can also produce dangerously low blood pressure. Most people who are killed by heat stroke die when their blood stops pumping effectively (circulatory failure). Even people who survive are likely to have permanent brain damage if their core temperature has been over 105°F (40.6°C) for more than an hour or two.

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