Heat Exhaustion and Heatstroke: What to Do?

Both heat exhaustion and heatstroke are ways the body reacts to excessive heat, but they differ greatly in severity and in their consequences. The first is usually mild if caught in time, while the second is a medical emergency that can be life-threatening.

Here's how to tell them apart, recognise their symptoms (including trembling, a question many people ask), and know exactly what to do in each situation.

Heat Exhaustion, Heatstroke, Sunburn: What's the Difference?

These three terms are often mixed up, wrongly so, since they refer to quite distinct conditions with very different levels of severity.

1. Sunburn, a Burn Limited to the Skin

Sunburn results from exposure to UV rays without sufficient protection, which is why using suitable sunscreen before any prolonged exposure matters. It is limited to the exposed skin. Symptoms include redness, a sensation of heat to the touch, and, in more severe cases, blisters. It is usually not accompanied by fever and remains harmless, provided you don't expose yourself again before it heals.

2. Heat Exhaustion, a Reaction to Direct Sun Exposure

Heat exhaustion occurs after direct, prolonged exposure of the head and neck to the sun. Unlike heatstroke, body temperature often stays close to normal or is only moderately raised.

It shows up as headaches, a red and hot face, dizziness, nausea and unusual fatigue. If caught in time — by moving into the shade and staying well hydrated — it is generally reversible within a few hours. Left untreated, however, it can progress into heatstroke.

3. Heatstroke, an Emergency Affecting the Whole Body

Heatstroke is the most serious of the three conditions presented here. It corresponds to a total failure of the body's thermal regulation system:

• body temperature rises above 39–40°C (102–104°F) ;
• the skin becomes hot and dry (sweating stops) ;
• neurological symptoms appear (confusion, disorientation, incoherent speech, or even seizures or loss of consciousness).

Good to know: unlike heat exhaustion, heatstroke can occur without any sun exposure at all. This can happen, for example, in a closed vehicle, a poorly ventilated room, or during intense physical exertion. It is a medical emergency that requires calling for help immediately.

Recognising the Symptoms of Heat Exhaustion or Heatstroke

Two signs help distinguish simple heat exhaustion from the onset of heatstroke: the person's neurological state and the state of their skin.

Here are symptoms that should alert you:

• Headaches, dizziness and ringing in the ears. These appear from the very first signs of overheating and are often accompanied by unusual fatigue ;
• A red, hot face, nausea or muscle cramps. These symptoms generally go hand in hand with heat exhaustion and ease with rest in the shade ;
• Difficulty breathing and a fast heart rate. The body compensates for overheating by speeding up its activity, which can come with unusual shortness of breath ;
• Hot but dry skin. The stopping of sweating is a warning sign that should raise suspicion of heatstroke rather than simple heat exhaustion ;
• Confusion, incoherent speech or unusual drowsiness. This neurological disturbance is the second distinctive sign of heatstroke, as the person themselves is often no longer able to recognise their own symptoms ;
• A high body temperature. Above 39–40°C, combined with the two previous signs, this confirms heatstroke.

Without prompt care, these symptoms can progress to seizures, loss of consciousness, or even coma. This life-threatening risk is exactly why you should act without delay.

Is Trembling a Sign of Heatstroke?

This question comes up often, and the answer deserves some nuance. Trembling is not among the classic diagnostic criteria for heatstroke, unlike dry skin, high temperature or confusion. It can nonetheless appear, particularly while the person is being cooled down: the body sometimes reacts with shivering, a paradoxical reflex that generates more heat. This is actually why lukewarm water is preferred over ice-cold water to cool someone suffering from heat exhaustion (unlike heatstroke), as it limits this shivering reflex.

If trembling appears alongside other, more characteristic signs (dry skin, confusion, high temperature), it should be taken seriously and viewed as part of an overall picture to monitor, rather than as an isolated symptom to interpret on its own.

What to Do in Case of Heat Exhaustion or Heatstroke

The Right Steps for Heat Exhaustion

• Move into the shade immediately. Get the person away from any heat source or direct sun exposure ;
• Loosen clothing. Remove unnecessary layers to help the body cool down naturally ;
• Moisten the face and the back of the neck. A cool cloth or lukewarm water applied to these areas helps the body return to a normal temperature ;
• Wipe off your sunscreen. If you're wearing any, it can slow down sweating ;
• Gradual rehydration. Have the person drink in small sips rather than a large amount all at once ;
• Monitor how things develop. Any worsening or the appearance of confusion should raise suspicion of heatstroke and lead you to call emergency services without delay.

What to Do for Heatstroke, a Medical Emergency

• Call emergency services immediately. 112 works throughout the European Union. Abroad, check our list of emergency numbers by country. When abroad, notify your travel assistance provider once local medical services have taken charge of the person.
• Cool the person down immediately. Partially undress them, fan them, and if possible apply damp cloths to the neck, armpits and groin ;
• Hydration in small sips. Give the person cool water to drink (never alcohol, which would speed up dehydration), unless they are confused or unconscious. The risk of choking becomes too high in that state: it's better not to give them anything to drink ;
• Immersion if a safe body of water is available. A cold bath, pool or stream speeds up cooling even further ;
• Constant supervision, especially during immersion. A confused person should never be left alone in water, due to the risk of slipping or losing consciousness.

For more information, the Belgian Red Cross offers a free guide dedicated to summer emergencies, worth keeping on your phone.

What Not to Do When Facing Heatstroke

Faced with an emergency, we may act on intuitive reflexes. Unfortunately, some of them can make the situation worse rather than better.

• Giving aspirin or paracetamol. These medicines treat fever caused by infection, not the overheating of heatstroke: they have no effect on body temperature in this context and can even worsen some symptoms ;
• Leaving the person alone, even for a few minutes. Their condition can rapidly tip into loss of consciousness ;
• Trying to give fluids to a person who is already losing consciousness or feeling faint, to avoid any risk of choking ;
• Fearing thermal shock and therefore avoiding a cold bath. The primary risk is a body temperature that is too high for too long, so cooling the body down must be the priority at all costs ;
• Waiting for it to "pass" before calling for help. Untreated heatstroke can progress to seizures or coma within a very short time ; it's better to call too early than too late.

Who Is at Risk From the Heat

The most vulnerable people when it comes to heat exhaustion and heatstroke are babies and young children, the elderly, pregnant women, people with cardiovascular or respiratory conditions, and those on certain medications (antidepressants, antipsychotics, neuroleptics). Workers exposed to heat (outdoor construction sites, greenhouses, laundries) and athletes engaging in intense exertion, however well trained, are not spared either — this is known as exertional heatstroke.

In young children especially, heatstroke can set in within just a few minutes inside a closed vehicle in full sun, even in weather that doesn't seem extreme from the outside.

Preventing Heat Exhaustion and Heatstroke on Holiday

A few targeted precautions clearly reduce the risk of heat exhaustion and heatstroke, both on holiday and in daily life.

• Protect the head and neck first. A wide-brimmed hat or cap directly limits the risk of heat exhaustion, as this is the most exposed area during prolonged sun exposure ;
• Acclimatise gradually to the heat. The first few days of exposure to unusual heat remain the riskiest, so it's best to ease off on physical effort while the body adapts ;
• Save physical exertion for the cooler hours. Sport and intense activities are best done early in the morning or in the evening, never during the peak midday heat ;
• Watch for early signs. Headaches, unusual fatigue or dizziness often signal the onset of heat exhaustion before it worsens: it's better to react early than to wait.
• Keep a close watch on children and vulnerable people. An effort that might seem trivial for someone in good health can become genuinely dangerous for someone more at risk once you add a heatwave into the mix.

Travel Insurance: What to Do in Case of Heatstroke Abroad

In case of heatstroke or severe heat exhaustion abroad, contact local emergency or medical services first. Then get in touch with your assistance provider. Travel insurance with medical assistance covers the costs related to this type of condition just like any other health issue, and arranges repatriation if necessary.

Travelling soon? Check that your travel assistance cover matches your destination. And to learn more, read our article on travelling during a heatwave!

Discover our travel insurance plans by clicking here

FAQ - Your Questions About Heat Exhaustion and Heatstroke