Recognising and Treating Heat Illness

Heat illness is a spectrum of conditions caused by the body's inability to cool itself adequately. From mild heat cramps to life-threatening heat stroke, each stage requires a different response. Knowing how to recognise each condition and respond correctly can prevent a serious emergency — and in the case of heat stroke, save a life.

The Spectrum of Heat Illness

Heat illness progresses in severity. Early recognition and treatment prevent advancement to the most dangerous stages.

Condition	Severity	Core Temperature	Key Feature
Heat cramps	Mild	Normal	Painful muscle cramps
Heat syncope	Mild	Normal or mildly elevated	Fainting in heat
Heat exhaustion	Moderate	37–40°C (98.6–104°F)	Heavy sweating, weakness, nausea
Heat stroke (classic)	Severe/Life-threatening	>40°C (>104°F)	Hot, dry or minimal sweat; confusion
Heat stroke (exertional)	Severe/Life-threatening	>40°C	Heavy sweating; confusion during exercise

Heat Cramps

Recognising Heat Cramps

• Painful, involuntary muscle spasms, typically in the legs, abdomen, or arms
• Occur during or after heavy exertion in heat
• Heavy sweating is common
• No confusion, no fever

Treatment

1. Stop all activity and move to a cool environment.
2. Rest in a comfortable position.
3. Rehydrate with cool water or a sports drink containing electrolytes.
4. Gently stretch and massage the affected muscle.
5. Do not return to strenuous activity for several hours.

⚠️ Heat cramps that do not resolve within an hour, or that occur in a person with heart disease or a low-sodium diet, should receive medical evaluation.

Heat Exhaustion

Heat exhaustion means the body is struggling significantly. It requires prompt action to prevent progression to heat stroke.

Recognising Heat Exhaustion

• Heavy sweating
• Cold, pale, clammy skin
• Fast, weak pulse
• Nausea or vomiting
• Muscle cramps
• Tiredness, weakness
• Dizziness or fainting
• Headache
• No confusion (key differentiator from heat stroke)

Treatment

1. Move the person to a cool place immediately — air-conditioned room, shade, vehicle with A/C.
2. Loosen or remove excess clothing.
3. Cool the person using cool, wet cloths on the skin, especially the neck, armpits, and groin.
4. Give cool water to drink if the person is conscious and not vomiting — small sips frequently.
5. Have the person lie down with legs elevated slightly (to improve circulation to the brain).
6. Fan the person to promote evaporative cooling.
7. Monitor closely — if the person vomits, loses consciousness, or becomes confused, call emergency services immediately. This indicates progression to heat stroke.
8. If symptoms do not improve within 15 minutes, call emergency services.

Heat Stroke

Heat stroke is a medical emergency. Without rapid cooling and emergency medical care, heat stroke can cause brain damage, organ failure, and death within minutes.

Recognising Heat Stroke

Classic heat stroke (common in elderly or those with chronic illness):

• High body temperature >40°C (104°F)
• Hot, dry skin (may be red)
• Rapid, strong pulse
• Confusion, altered mental state, slurred speech
• Loss of consciousness possible
• Little or no sweating

Exertional heat stroke (common in athletes and workers):

• High body temperature >40°C (104°F)
• Hot skin that may still be wet from sweating
• Confusion, irrational behaviour, aggression
• Loss of coordination
• May also have nausea and vomiting

Treatment — Act Immediately

1. Call emergency services (000/911/112) immediately.
2. Move the person to the coolest available environment — air conditioning is ideal.
3. Begin aggressive cooling without delay:
   • Ice-water immersion (best method if available): submerge the body to the neck in ice water
   • Cold wet towels or ice packs to the neck, armpits, and groin (major blood vessels)
   • Spray the person with cool water and fan vigorously
4. Do not give fluids — a confused person cannot safely swallow.
5. Do not give aspirin or paracetamol — these do not help heat stroke and aspirin may cause additional harm.
6. Keep cooling until emergency services arrive. The goal is to reduce body temperature as fast as possible — every minute matters.
7. If the person loses consciousness, place in the recovery position and monitor breathing.

Method	Effectiveness	Notes
Ice-water immersion	Fastest (reduces temp ~0.2°C/min)	Best for exertional heat stroke
Ice packs to neck/axilla/groin	Good	Immediately available option
Cold wet towels + fanning	Moderate	Use if nothing else available
Shaded rest only	Inadequate for heat stroke	Not sufficient — continue active cooling

Special Populations

Elderly

Classic heat stroke is more common in the elderly because they sweat less and have reduced cardiovascular reserve. During heat waves, check on elderly neighbours and relatives daily.

Children

Children produce more heat relative to their body weight and rely on caregivers to move them to cool environments. Never leave children in parked vehicles — car interior temperatures can reach lethal levels within minutes.

Athletes and Outdoor Workers

Exertional heat stroke is common in this group. Training during the hottest part of the day, dehydration, and peer pressure to "push through" warning signs all increase risk. Acclimatisation — gradually increasing exposure over 10–14 days — significantly reduces risk.

Prevention

Strategy	Details
Hydration	Drink water regularly, especially before feeling thirsty — 500mL per hour during exertion in heat
Timing	Avoid strenuous activity during peak heat hours (10am–4pm)
Clothing	Light-coloured, loose-fitting, moisture-wicking fabric
Acclimatisation	Gradually increase heat exposure over 10–14 days
Buddy system	Check on each other frequently during outdoor work or sport
Rest breaks	Frequent breaks in shade or air conditioning
Cooling stations	Know the location of public cooling centres in your community

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Quick Reference

Condition	Key Sign	Immediate Action
Heat cramps	Muscle spasms, sweating, no confusion	Rest, rehydrate, stretch
Heat exhaustion	Heavy sweat, pale, weak, no confusion	Cool place, cool cloths, fluids, lie down
Heat stroke	Confusion, high temp, hot skin	Call 000/911, AGGRESSIVE cooling, no fluids by mouth
Child/elderly unresponsive in heat	Assume heat stroke	Call 000/911, cool immediately