Heat exhaustion occurs when your body overheats due to prolonged exposure to high temperatures, especially when combined with high humidity and strenuous physical activity. : Heat stroke (also called sunstroke) is a severe, life-threatening condition in which the body’s temperature regulation system fails and the core temperature rises above 40°C (104°F). It can occur quickly, often following untreated heat exhaustion or extensive exposure to a hot environment or intense physical exertion.
This article explains how to recognise the signs and symptoms of heat-related illness, how to provide first aid for heat stroke, and when to call an ambulance in Australia.
Be prepared for every emergency – Enrol in a nationally recognised first aid course with First Aid Pro and learn how to treat heatstroke, heat exhaustion, and other heat-induced conditions.
Key Takeaways
- Heat stroke is a severe, life-threatening condition – act fast.
- Recognise symptoms of heat stroke: high body temp, confusion, dry skin, fainting.
- Always call 000 and begin cooling measures immediately.
- Know the difference between heat exhaustion and heat stroke.
- Stay cool, stay hydrated, and get trained – first aid saves lives.
Don’t wait for an emergency – Enrol in a nationally recognised first aid course with First Aid Pro and be prepared to act.
What Is a Heat-Related Illness?
A heat-related illness refers to a spectrum of medical conditions that occur when the body is unable to properly cool itself in hot environments, leading to overheating and potential organ dysfunction. These illnesses range in severity and include dehydration, heat cramps, heat exhaustion, and heat stroke—the latter being a life-threatening emergency.
Heat-related illnesses can present with symptoms such as heavy sweating, weakness, dizziness, headache, nausea, vomiting, rapid pulse, tiredness, irritability, confusion, fainting, and in the most severe cases (heat stroke), high body temperature, confusion, seizures, or unconsciousness.
If untreated, mild forms like dehydration and heat cramps can progress to more severe conditions such as heat exhaustion and heat stroke.
Heat-induced illness is caused by exposure to high temperatures, especially when combined with high humidity and physical exertion, which disrupts the body’s ability to regulate its internal temperature. Everyone is at risk, but infants, the elderly, and people with chronic health conditions are particularly vulnerable.
Summary of Heat-related illnesses:
Condition | Description |
Heat rash | Skin irritation from excessive sweating |
Heat cramps | Muscle spasms due to loss of salt through sweat |
Heat exhaustion | Severe fluid loss leading to fatigue, weakness, and dizziness |
Heat stroke | A life-threatening rise in core body temperature, requiring emergency medical aid |
Australia regularly experiences extreme heat, and according to the National Museum Australia, heat kills more Australians than any other natural hazard, especially among babies and young children, the elderly, and people with existing medical conditions.
Signs and Symptoms of Heat Stroke
Heat stroke often develops quickly, but symptoms may follow signs of heat exhaustion. Prompt recognition is critical.
Symptoms of Heat Stroke
Very high body temperature (core temperature of 40°C or higher)
Altered mental state or behaviour: confusion, agitation, delirium, irritability, slurred speech, seizures, or unconsciousness
Changes in sweating: skin may be hot and dry (especially in classic heat stroke), but may still be sweaty in cases related to intense physical exertion
Flushed, red skin
Nausea and vomiting
Rapid, shallow breathing
Racing heart rate (tachycardia)
Throbbing headache
Muscle twitching or seizures
Loss of consciousness
Heat stroke is a medical emergency—if you suspect someone has heat stroke, call emergency services and begin cooling them while waiting for professional help.
When to Call an Ambulance
If someone shows symptoms of heat stroke, treat it as a medical emergency and call Triple Zero (000) immediately. Delay in treatment can lead to organ damage, permanent disability, or death.
Heat Exhaustion and Heat Stroke – What’s the Difference?
Heat exhaustion and heat stroke are both heat-related illnesses but differ significantly in severity. Heat exhaustion is less dangerous and results from the body losing too much water and salt through heavy sweating, with symptoms like weakness, dizziness, headache, nausea, and cool, clammy skin; it can usually be treated with rest, hydration, and cooling down.
Heat stroke, on the other hand, is a life-threatening emergency where the body’s temperature regulation fails, causing a very high body temperature (above 40°C), confusion or unconsciousness, hot and dry (or sometimes sweaty) skin, and sometimes seizures—immediate emergency medical attention is required to prevent permanent damage or death.
- Heavy sweating or no sweating
- Muscle cramps
- Weakness or fatigue
- Dizziness
- Nausea or vomiting
- Headache
- Cool, moist skin
- Fast, weak pulse
- Move to cool, shaded area
- Remove excess clothing
- Apply cool water to skin
- Give cool fluids to drink
- Rest and monitor closely
- Seek medical attention if severe
- High body temperature (40°C+)
- Hot, dry skin or profuse sweating
- Altered mental state
- Confusion or delirium
- Loss of consciousness
- Rapid, strong pulse
- Severe headache
- Seizures possible
- Call 000 immediately
- Cool rapidly - ice packs to neck, armpits, groin
- Remove clothing
- Fan while applying water
- Monitor breathing and pulse
- Do NOT give fluids if unconscious
Emergency Action Steps
First Aid for Heat-Induced Conditions
Step-by-Step First Aid for Heat Stroke
First aid must be rapid and systematic - this is a life-threatening emergency
- Move the person out of the sun and into a shaded area
- Ideally move to an air-conditioned area
- If inside, ensure good airflow
- Lay the person flat
- If possible, raise their legs slightly
- This helps maintain blood flow to vital organs
- Remove as much clothing as possible to help the body cool
- Loosen any tight items
- If the person is awake and able to swallow safely, offer cool, non-alcoholic, non-caffeinated drinks
- Water or sports drinks with electrolytes are best
- Continuously monitor breathing and responsiveness using the DRSABCD protocol
- Be ready to start CPR if the person becomes unconscious and is not breathing normally
- Observe for worsening symptoms or any deterioration
- Continue cooling efforts until emergency responders take over
- Update ambulance dispatcher if condition changes
First Aid for Heat Exhaustion
Urgent but less intensive than heat stroke - cool and rehydrate before symptoms progress
- Encourage them to sit or lie down
- Ideally with legs slightly raised to help circulation
- Loosen or remove tight or heavy clothing
- Allow the body to cool naturally
- Stay with the person and observe for improvement
- Monitor breathing, consciousness, and temperature
Related Conditions and Symptoms to Watch For
Heat affects everyone differently. Here are other heat-induced conditions to be aware of:
Condition | Signs |
Heat rash | Red, itchy skin – often in folds of the skin like armpits or groin |
Heat cramps | Painful muscle spasms during or after exercise |
Dehydration | Thirst, dry mouth, reduced urine output, fatigue |
Heat fatigue | Feeling tired and unwell after prolonged sun exposure |
These symptoms may worsen existing medical conditions or trigger sudden events like a heart attack or stroke.
High-Risk Groups for Heat Stroke in Australia
Some groups are more likely to suffer from heat exhaustion or heat stroke:
Prevention Tips – Managing Heat Risk in Australia
Australians must be vigilant during hot days, especially in areas where temperatures reach 40°C or more.
Tips to Prevent Heat-Related Illness:
- Drink plenty of water, even if not thirsty
- Wear loose, light-coloured clothing
- Avoid physical activity during the hottest parts of the day (11am–3pm)
- Stay in air-conditioned spaces when possible
- Never leave children or pets in parked cars
- Check in on vulnerable people during heatwaves
Stay prepared – Enrol in a nationally recognised first aid course with First Aid Pro and learn how to manage medical emergencies caused by extreme heat.
Knowledge Test Quiz: Are You Heat Smart?
Test your understanding of heat-related illness and first aid
References
Safe Work Australia: Working in Heat
Queensland Health: Health experts the hot tip for sun safety advice
International Paramedic College: First Aid for Heatstroke
Australian Resuscitation Council: Guideline 9.3.4 – Heat Induced Illness (Hyperthermia)
Healthdirect: Heatstroke
