First aid for heat-related illness

This page provides guidance on first aid for heat-related illness. It includes what to do in the case of dehydration, heat rash and cramps, and fainting. If you think a person may have heat exhaustion or heat stroke, call an ambulance immediately. 

As a person conducting a business or undertaking (PCBU), you have a duty to provide first aid for sick or injured workers, including providing: 

  • first aid equipment and facilities 

  • access to trained first aid officers.  

Working in a hot environment—indoors or out—can put workers at risk of heat-related illness. 

Check worker medications and medical conditions 

If a worker is on certain medications, has a pre-existing medical condition or has had heat-related illness before, they’re more susceptible to a heat-related illness. This can also affect how the worker should be treated.  

You should alert workers to this risk and monitor them closely, as far as is reasonably practicable.   

Dehydration symptoms 

Seek medical advice if symptoms don’t improve or are severe. 

Dehydration symptoms include: 

  • mild to severe thirst (remember that thirst is satisfied before fluid loss is fully replaced) 

  • dry lips and tongue 

  • slowed mental function and lowered performance 

  • reduced or dark urine output. 

First aid for dehydration 

  • Drink water.  

  • Avoid caffeinated, carbonated and alcoholic drinks, and salt tablets. 

  • Loosen tight clothing and remove unnecessary clothing, including personal protective equipment (PPE). 

  • In cases of extreme heat or dehydration, replace electrolytes. 

Heat rash  

Heat rash is an itchy rash with small raised red spots on the face, neck, back, chest or thighs. 

Seek medical advice if symptoms don’t improve. 

First aid for heat rash 

  • Move worker to a cooler, less humid environment. 

  • Keep the affected area dry and remove unnecessary clothing, including PPE. 

  • Apply a cold compress. 

Heat cramps symptoms  

Heat cramps are painful and often incapacitating cramps in muscles, particularly when doing demanding physical work. 

Seek medical advice if symptoms don’t improve. 

First aid for heat cramps 

  • Stop activity and have the worker rest quietly in a cool place until recovered. 

  • Give the worker an electrolyte solution. 

Fainting symptoms  

Fainting (heat syncope) can happen while standing or rising from a sitting position. 

Seek medical advice if a worker faints. 

First aid for fainting 

  • Lie the worker flat immediately with their legs slightly raised. 

  • Do not raise the head. 

  • Treat as for heat stroke. 

Call ambulance immediately if heat stroke is suspected 

Heat stroke symptoms include: 

  • dehydration, thirst, and reduced or dark urine output 

  • sweating 

  • elevated body temperature 

  • weakness or fatigue 

  • headaches and dizziness 

  • nausea 

  • muscle cramps. 

Severe symptoms include: 

  • the worker stops sweating 

  • skin can be pink, warm and dry, or cool and blue 

  • clumsiness or slower reaction times 

  • disorientation or impaired judgement 

  • rapid or short breathing 

  • rapid weak pulse, pounding pulse or heart palpitations 

  • tingling or numbness in fingers or toes 

  • visual disturbance 

  • vomiting or an unwillingness to drink.  

  • irritability and mental confusion 

  • collapse, seizures and unconsciousness 

  • cardiac arrest (the worker is unconscious, has stopped breathing and has no pulse). 

Not all heat-induced illness symptoms will be present. 

First aid for heat-induced illness 

  • Call 000 and evacuate by ambulance immediately  

  • Update the ambulance if the worker seizes or becomes unconscious and follow all directions given by emergency crew 

  • Follow all instructions given by ambulance operator 

  • If cardiac arrest occurs, follow DRSABCD action plan 

  • Move the worker to a cool place with circulating air. 

  • Lie the worker flat. 

  • Remove unnecessary clothing, including PPE. 

  • Loosen tight clothing. 

  • If practicable, immersion in a bath of cold water is the most effective cooling means possible. 

  • Immerse the worker (whole-body from the neck down) in a bath of cold water (preferably 1–7˚) for 15 minutes. 

  • Continuously observe the worker to ensure an open airway in case of any change in their level of consciousness. 

  • If cold bath is not available, or is not reasonably practicable to use, use a combination of the following as available: 

  • Cool the worker by splashing cool or cold water on their skin or sponging their skin with a damp cloth. 

  • Make a wind tunnel by suspending sheets around – not on – the worker’s body, and use a fan to direct gentle airflow over the worker’s body. 

  • Apply cold packs or wrapped ice to the worker’s neck, groin and armpits. 

  • Give an electrolyte solution with sugar – do not attempt to give oral fluid if the worker is not fully conscious. 

Shivering is an automatic muscular reaction which warms the body. It will make the body temperature rise even further.  

If the worker starts shivering: 

  • stop cooling immediately and cover them until they stop 

  • once they have stopped, recommence first aid treatment. 

Supporting information