Sharon has 21+ years of experience as a qualified Emergency Care Nurse registered with the Australian Health Practitioner Regulation Agency (APHRA) and 12+ years as a First Aid Trainer.
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Recognising the Signs and Symptoms of Heat Exhaustion
Heat exhaustion is an extremely serious issue caused by the human body responding to a loss of hydration or the salt contained in sweat. While perhaps not as well known as heatstroke, it can quickly escalate into heatstroke, making it just as dangerous.
While heat exhaustion is not deadly in its own right, recognising its symptoms is essential to treating it as soon as possible. A professionally delivered first aid course can help you identify the signs and symptoms of heat exhaustion and prevent it from escalating into heatstroke.
What Are the First Signs of Heat Exhaustion?
The first step in preventing heat exhaustion is to identify its symptoms, many of which are unfortunately common and may occur in non-heat-related illnesses. As such, if symptoms of a heat-related illness appear, it is important to first ask if heat exhaustion is the most likely explanation.
Are you in a situation with hot weather, extreme sunlight, or undergoing strenuous physical activity? Are you experiencing more than one symptom? If not, there may be a more straightforward explanation.
However, if you or someone you know is showing symptoms in a situation where heat exhaustion is likely to develop, these are the symptoms you should be looking out for:
Heavy sweating
In extremely hot weather, changes in body temperature and excessive sweating are to be expected. Heavy sweating can be differentiated from regular sweating, as your skin will turn cool and moist.
A significant reduction in sweating is often a symptom that heat exhaustion has become heatstroke, as it may indicate your body is running out of fluids it can draw on to cool your skin, and dehydration is near.
Paleness
A loss in hydration can lead to a loss of colour in your skin.
Changes to pulse or breathing.
When your body senses something is wrong, it works harder, even if it has less energy as a result of dehydration. A pulse that is faster but weaker, or faster, yet shallower breathing are signs of heat exhaustion.
Muscle weakness or cramps
Muscle cramps are common symptoms after undergoing strenuous physical activity. When combined with other symptoms, heat cramps are a likely possible sign of heat-related illness.
Tiredness and Fatigue
Exhaustion is a common symptom of heat exhaustion, especially if your level of tiredness is much higher than usual.
Headache, Dizziness, or Confusion
Heat exhaustion can lead to a drop in blood pressure, which in turn can affect your mind with one or more of these symptoms.
Nausea, vomiting, or fainting
These are the most extreme symptoms. If you or someone you know exhibits one of these signs, heatstroke is likely close, and you should seek help or provide immediate first aid.
Differentiating Between Symptoms of Exhaustion and Heat Exhaustion
Undergoing intense physical activity can lead to both exhaustion and heat exhaustion symptoms, especially in hot weather or for those with high blood pressure. Say you’ve just spent a long day out hiking, you should expect to be tired. This makes telling the difference between the two difficult, particularly as exhaustion in its own right is a common symptom of heat-related illness.
Regular exhaustion basically has no other symptoms other than itself. Tiredness and drops in mood or productivity are to be expected, but when combined with other symptoms, it may be heat exhaustion.
Can Heat Exhaustion Cause Fever the Next Day?
Heat exhaustion fever is possible. However, excessive sweating results in a lower-than-normal body temperature, making a fever an unlikely consequence. When a fever does occur, it is almost immediate, and so heat exhaustion fever the next day is particularly unlikely.
Understanding the Duration of Heat Exhaustion

How long heat exhaustion lasts depends on the severity of the case and how soon treatment is sought. If appropriate first aid is not applied soon enough, it can turn into heatstroke in as quick as ten to fifteen, though in some circumstances it may develop over hours or even days.
It also takes much longer to recover from, usually between 24 and 48 hours. This can be reduced depending on the seriousness of the case, and by efficiently providing the correct first aid.
Administering First Aid for Heat Exhaustion

If you recognise heat exhaustion symptoms in yourself or someone else, it is essential to administer proper first aid as soon as you can. In doing so, you can not only help someone recover, but you can also prevent heat exhaustion from developing into potentially deadly heatstroke.
By successfully completing a professionally delivered first aid course, you can provide better and more appropriate to a wide variety of medical situations. This allows you to best ensure that a victim of heat exhaustion recovers and that they recover as soon as possible.
Essential First Aid Steps for Heat Exhaustion
In the event of heat exhaustion, the first step is always to gently move the victim out of the heat and into a cool place. Laying them down into a horizontal position is also always paramount. Next, remove or loosen any excess or tight clothing, which can exacerbate their condition in hot weather.
If you have cold or cool water on hand, use it to immerse the person’s hands and feet, lowering their body temperature. Keep their skin moist, using cold packs if possible, and fan them to keep them cool. Give the person water, but only in small sips and only if they are fully alert and responsive. Do not give them any alcoholic or caffeinated beverages.
Finally, always seek professional medical help as soon as possible.
Treatment for Heat Exhaustion at Home
Treating heat exhaustion in the home is made easier thanks to access to shade and cool water, but that doesn’t mean it should be considered any less dangerous. Treat heat-related illness in the home with the same care and caution you would use anywhere else.
Move the person out of direct sunlight and, if possible, into an air-conditioned space. Laying them down is still paramount, and as such it is important to avoid the temptation of putting them into a cool shower to lower their body temperature.
When to Seek Medical Help for Heat Exhaustion
The best treatment is always prevention. The next best time to seek help is as soon as symptoms present. If you haven’t completed a first aid course or cardiopulmonary resuscitation course and aren’t able to provide the proper assistance, then professional medical help should be sought immediately.
Frequently Asked Questions
How long does it take to recover from heat exhaustion?
If treated immediately, it can take between 24 and 48 hours for someone to fully recover.
What is the fastest way to recover from heat exhaustion?
The fastest way to recover from heat-related illnesses is to seek professional medical help immediately. Bearing this, move out of the heat and into a cool place, lay down, immerse your hands and feet in water, and slowly sip cool water.
What can be mistaken for heat exhaustion?
As many symptoms of heat exhaustion are common, there are plenty of other ailments it may be confused for. A few simpler conditions that may affect body temperature and be mistaken for heat-related illness include allergies, depression or anxiety, motion sickness, a fever or cold, or a migraine.
How do you feel after heat exhaustion?
In addition to external sensations such as excessive sweating, those suffering from heat exhaustion can feel internal changes such as weaker breathing, tiredness and fatigue, headaches, dizziness, and confusion. A victim of heat exhaustion may continue to experience these symptoms until they have fully recovered.
How is this different to heat stroke?
While some might use the terms heat stroke and heat exhaustion synonymously, they are not the same. Exhaustion describes the body’s reaction to excessive heat. On the other hand, heat stroke is a severe version of exhaustion, characterized by distinct symptoms. These symptoms indicate that the body’s overheating is reaching a critical, potentially fatal level.