Heatstroke & Sunstroke – Causes, Symptoms, Treatment, Prevention

Heatstroke is a serious condition that occurs when your body’s core temperature increases significantly. The normal human body temperature is 37 degrees celsius and when your temperature passes 40 degrees celsius, you can suffer with a heatstroke. A heatstroke is caused by high environmental temperatures and when this is due to excessive sun exposure, it is known as a sun stroke.

Causes of a Heatstroke

Hot environmental conditions as a result of the sun, industrial equipment or in confined and poorly ventilated spaces like a mine can lead to a heatstroke (classical heatstroke). Even strenuous activity will raise your metabolism and increase heat production and if it reaches a high temperature, you can suffer with a heat stroke (exercise-induced). Some drugs and alcohol may also contribute to the development of a heatstroke, especially if they cause you to pass out water and electrolytes.

A heatstroke usually does not occur suddenly with no warning. First you may develop heat cramps or heat exhaustion and this progresses to a heatstroke if you do not take any preventative measures.

Signs and Symptoms

Heat Cramps

Initially you may notice the signs and symptoms of heat cramps which include :

  • Fatigue.
  • Excessive thirst.
  • Profuse sweating.
  • Muscle cramps, particularly stomach, arms and leg cramps.
  • Dizziness or even fainting spells.

Heat Exhaustion

If you do not take any measures to cool down your body temperature, avoid further heat and reduce physical activity, your condition will progress to heat exhaustion. Signs and symptoms of heat exhaustion include the symptoms above in addition to :

  • Headaches.
  • Nausea.
  • Listlessness or confusion.
  • Cold and clammy skin.


With a heatstroke, you may experience some or all of the symptoms of heat cramps and heat exhaustion as well as :

  • High body temperature (higher than 40 degrees).
  • Rapid, shallowing breathing.
  • Increased heart rate.
  • Palpitations (fast and/or ‘hard’ heart beat).
  • Flushing of the skin (redness).
  • Reduced or no sweating.
  • Seizures (fits), hallucinations and/or confusion.

Without treatment at this point, you may go into shock and this may be seen as blue lips and fingers, low blood pressure and paleness of the skin.

Treatment of a Heatstroke

The focus of treatment will revolve around lowering your body temperature. This may include a cold shower or immersing a patient in an ice bath. Spreading cool water over the skin and using a cooling blanket may be other options.

If you are shivering excessively, then your doctor may administrate muscle relaxants to prevent this because the muscle movements when shivering increases your body temperature. To treat the dehydration, your doctor may also administer fluids and electrolytes through an IV drip.


In most cases, a heatstroke can be prevented if you constantly rehydrate yourself, wear cool, light clothing and avoid strenuous activity in hot conditions.

During summer, heatstrokes are common especially in children and the elderly. Labourers are also at risk when working in the heat. Avoiding direct exposure to the sun and resting in a cool place is also important. Be careful of sitting in a closed car that is parked in the heat as this is one of the main causes of a heatstroke in children who are left unsupervised.

Drinking water is not enough. You will need to drink fluids with electrolytes like sports drinks. Avoid carbonated soft drinks as these may contain caffeine which will cause you to pass out more water and electrolytes through your urine. Even tea or coffee can be a problem. Although you may feel for a cold beer, this is not advisable as alcohol also dehydrates you.