How To Tell The Difference Between Heat Exhaustion And Heat Stroke

Heat Exhaustion or Heat Stroke

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Heat Exhaustion or Heat Stroke

Having knowledge of First aid treatment for heat exhaustion and first aid treatment for heatstroke is important and can also be life-saving information. These are the most serve forms of heat-induced illness. The two conditions share similar symptoms, so it is important to understand how they differ and identify the differences.

What are the differences between heat exhaustion and heat stroke?

The main difference between heat exhaustion and heat stroke is that having heat stock is a life-treating medical emergency and needs to be treated immediately. Heat exhaustion is less serious than heat stroke and other heat-related illnesses. Both illnesses are caused when there is a dramatic rise in a person’s body temperature. Heat exhaustion is when a person’s body rises to temperatures above 36c – 37c, which is the normal resting temperature of a human body. However, when the body reaches temperatures 40c or over, the possibility of heatstroke rises, and the body goes into a critical condition.      

What Is Heat Exhaustion


Heat-related illnesses like Heat exhaustion are caused by a rise in body temperature over 37c-40c and are often accompanied by dehydration. Dehydration creates a deficit of essential salts or electrolytes in the body along with a large amount of water due to excessive sweating. The body deals with internal heat by pumping blood to the skin’s surface to release sweat, and when dehydration hits, it causes a decline in sweating. When the body becomes unable to cool down with sweating, it becomes vulnerable to heat exhaustion. As the body loses fluids and salts from decreased blood pressure after continued exposure to high heat, it may lead to fatigue and heat cramps that are signs of Heat Exhaustion.  

Symptoms to look out for when identifying heat exhaustion are:

  • Heavy sweating 
  • Dilated pupils
  • Weak or rapid pulse
  • Rapid or shallow breathing
  • Light-headedness from Low blood pressure when standing or bending over
  • Muscle weakness or cramps   
  • Headaches
  • Dizziness
  • Red or flushed face    
  • Nausea or vomiting
  • Irritable or aggressive behaviour
  • Cold, pale, damp skin is sometimes followed by goosebumps

Symptoms of Heat Stroke In Children

In children, symptoms of heat exhaustion have similar signs to heat exhaustion in adults. Children may have:

  • Be unusually thirsty
  • Have cool or clammy skin
  • Seem to be extremely fatigued
  • If they are old enough to communicate, they may complain about cramping in their legs or stomach.  

Treat children with signs of heat exhaustion immediately so as to not become worse. 

Heat exhaustion can be classified in two ways:

Water depletion- experiencing extreme thirst, muscle weakness, headaches and risk of loss of consciousness.

Salt depletion- signs of lack of salt in the body are nausea, vomiting, muscle cramps and dizziness.

Although heat exhaustion is not as life-threatening as heat stroke, it is a serious heat illness all the same. Not intervening in heat exhaustion or not managing the symptoms can lead to becoming or progressing heatstroke. With proper treatment for heat exhaustion, the symptoms will be able to improve within half an hour or 30 minutes. Most fully recover from heat exhaustion after 24-48 hours after treatment. Professional Medical attention needs to be sought out if symptoms progress longer than 40-60 minutes without any improvement. Professional treatment for heat exhaustion will likely involve 1-2 litres of intravenous or IV fluids and electrolytes. If there is no improvement after a fluid injection, blood work and other tests will be done to find the potential cause.    

What Is Heat Stroke

Heat Induced Illness

It is critical to receive first aid treatment for heatstroke as it is the most severe of the heat-related illnesses. Medical intervention needs to be done immediately to avoid possible damage to the brain, heart, kidneys and muscles. It may also lead to a coma or even death if left untreated. Heatstroke also goes by sunstroke and is associated with body temperatures that are over 40c.

It is known as ‘core temperature emergency’ when the body overheats, reaching a core temperature of over 40c within 10-15 minutes, and the brain ceases to function properly. The first aid treatment is to quickly cool down the body temperature before emergency services arrive. The signs of heatstroke are dry skin or lack of sweat, rapid, shallow breathing, and pupil concentration.

What Are The Symptoms of heatstroke       

  • Nausea and vomiting
  • Headache
  • Skin reddening as body temperature increases
  • Skin will be hot and dry when brought on by strenuous exercise, and skin may feel dry or only slightly moist 
  • Rapid pulse places stress on the heart as the body deals with the heat
  • An altered behaviour or mental state includes signs of delirium, irritability, slurred speech, confusion, agitation, seizures, or even a coma.

Using first aid on heatstroke quickly and effectively will take about one to two days in the hospital to fully recover. There may be cases of organ damage caused by swelling, or recovery will take a lot longer. Organ damage ranges from mild to severe, and the prognosis changes if complications arise in the person’s condition. If there is permanent damage to the brain, lungs, liver, or kidneys, there will be chronic medical issues from heatstroke.     

How to prevent a heat-induced illness

Sweating is the body’s natural defense against excessive ongoing heat as it dissipates heat through the skin and lung moisture evaporation. So, wearing loose, light-coloured clothing is preferred in warmer weather. Avoid strenuous activities like training, long-distance running or jogging, or playing sports in overly hot weather. If you start feeling weak or have muscle cramps, stop whatever activity you are doing immediately and go to cool down. Avoid spots with constant direct sun and avoid sitting in closed cars in warm weather, as this is the most common cause of children getting heatstroke.

Air conditioning is more effective than fans in quickly cooling down and lowering the humidity in a room. Staying hydrated, if you have to empty your bladder only infrequently, you need to increase your intake of fluids immediately. Drinks like ‘sports drinks’ are a good way to hydrate quicker. It is also best to avoid any alcohol if you start having any signs of heat illness.                   

Medications like diuretics, stimulants or sedatives can increase the risk of stroke so check with your doctor or pharmacist about any effects. If you plan to go into a hotter climate, get yourself time to adjust to it. This means limiting your outdoor activities or slowing down your activities if you are prone to heat illnesses for a day or two. To gain further tips for preventing Heat-Related Illness check out the report conducted by Centers for disease control and prevention Tips for Preventing Heat-Related Illness | Natural Disasters and Severe Weather | CDC

It should be noted that this information is for general knowledge and management of heat illnesses and does not replace any form of first aid training.     

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