Heat Exhaustion and Heatstroke:
Recognising and Responding to Heat-Related Illnesses

Heat exhaustion and heatstroke are serious conditions that occur when the body becomes overheated. These conditions can develop quickly, especially in hot, humid environments or during strenuous physical activity. Left untreated, heat exhaustion can progress to heatstroke, a life-threatening emergency. Knowing the signs and how to respond can prevent severe complications or death.

What is Heat Exhaustion?

Heat exhaustion occurs when the body loses too much water and salt through sweating, making it difficult to regulate internal temperature. It can happen after prolonged exposure to high temperatures, especially when combined with physical exertion. Heat exhaustion is not immediately life-threatening, but it requires prompt attention to prevent it from progressing to heatstroke.

What is Heatstroke?

Heatstroke is a medical emergency that happens when the body’s core temperature rises to dangerous levels (above 40°C or 104°F) and the body’s cooling mechanisms fail. It can cause damage to vital organs and lead to death if not treated quickly.

Causes of Heat Exhaustion and Heatstroke

Heat-related illnesses can be caused by:

• High Temperatures and Humidity: Prolonged exposure to hot, humid weather can lead to dehydration and overheating.
• Physical Exertion: Strenuous activities like running, hiking, or working outdoors in the heat can increase the risk of heat exhaustion or heatstroke.
• Dehydration: Not drinking enough water to replace fluids lost through sweating can contribute to heat exhaustion.
• Inappropriate Clothing: Wearing heavy or non-breathable clothing in hot weather can prevent the body from cooling down properly.

Signs and Symptoms of Heat Exhaustion

Heat exhaustion is characterised by a range of symptoms, including:

• Heavy Sweating: The person may sweat excessively as their body tries to cool down.
• Pale, Cool, and Clammy Skin: The skin may feel cold and damp to the touch, despite the hot environment.
• Weakness or Fatigue: The person may feel extremely tired or weak.
• Dizziness or Fainting: They may feel light-headed or faint due to the drop in blood pressure caused by dehydration.
• Nausea or Vomiting: The person may feel sick or vomit as the body struggles to cope with the heat.
• Headache: A throbbing headache may develop due to dehydration and overheating.
• Muscle Cramps: Painful cramps, particularly in the legs or abdomen, can occur due to the loss of salt through sweat.

Signs and Symptoms of Heatstroke

Heatstroke is a life-threatening condition and requires immediate medical attention. Symptoms include:

• No Sweating: Unlike heat exhaustion, the person may stop sweating even though their skin is hot and dry.
• Flushed, Hot Skin: The skin may appear red and feel very hot to the touch.
• Rapid, Shallow Breathing: The person may breathe quickly and shallowly.
• Fast, Strong Pulse: A rapid heartbeat is common as the body struggles to cool down.
• Confusion or Agitation: The person may appear confused, irritable, or disoriented. They may also have trouble understanding or responding to questions.
• Seizures: In severe cases, heatstroke can cause seizures or convulsions.
• Loss of Consciousness: The person may become unresponsive or lose consciousness as their body temperature continues to rise.

First Aid for Heat Exhaustion

1. Move the Person to a Cool Place:

• Get the person out of the heat immediately. Move them to a shaded, cool, or air-conditioned area.

2. Help Them Rehydrate:

• Encourage the person to drink cool water or an electrolyte drink (such as a sports drink) to replenish fluids and salts lost through sweating. Avoid giving them caffeine or alcohol, as these can worsen dehydration.

3. Cool Their Body:

• Help the person cool down by loosening or removing excess clothing. Apply cool, damp cloths to their skin or sponge them with cool water. You can also fan the person to help evaporate sweat and cool the skin more quickly.
• If possible, have the person take a cool shower or bath.

4. Monitor Their Condition:

• Stay with the person and keep an eye on their symptoms. If they do not improve within 30 minutes or their condition worsens, seek medical help.

First Aid for Heatstroke

Heatstroke is a medical emergency, and immediate action is required to prevent serious complications or death.

1. Call 999 Immediately:

• Dial 999 for emergency help if you suspect someone is suffering from heatstroke. This is a life-threatening condition that requires urgent medical attention.

2. Move the Person to a Cool Place:

• Like with heat exhaustion, move the person to a shaded, cool area or an air-conditioned space.

3. Cool the Person Rapidly:

• Begin cooling the person as quickly as possible. Remove any excess clothing and apply cool water to their skin. If possible, place them in a cool or cold bath to lower their core body temperature.
• If a bath is not available, place ice packs or cold compresses on the person’s armpits, groin, neck, and back – these areas are where blood vessels are close to the skin and cooling them can help lower body temperature quickly.

4. Monitor Breathing and Consciousness:

• Stay with the person and monitor their breathing, pulse, and level of consciousness. If they become unresponsive or stop breathing, be prepared to start CPR and call 999 again for further instructions.

Prevention of Heat Exhaustion and Heatstroke

• Stay Hydrated: Drink plenty of water throughout the day, especially when exercising or working in hot weather. Sports drinks can help replace lost electrolytes during heavy physical activity.
• Avoid Overexertion: Limit strenuous activities during the hottest part of the day, usually between 11 am and 3 pm. Take frequent breaks in the shade or indoors.
• Wear Light Clothing: Wear loose, lightweight, and light-coloured clothing that allows your skin to breathe and helps your body stay cool.
• Use Sun Protection: Apply sunscreen, wear a wide-brimmed hat, and use sunglasses to protect yourself from direct sunlight.
• Know Your Limits: Pay attention to your body and stop activities if you feel dizzy, weak, or excessively sweaty. Seek shade and rest if you start to feel unwell.

When to Seek Medical Help

• For Heat Exhaustion: If symptoms do not improve within 30 minutes after moving to a cooler environment and rehydrating, seek medical help. Persistent symptoms could indicate heatstroke.
• For Heatstroke: Always call 999 immediately. Heatstroke is a medical emergency, and delaying treatment can lead to organ damage or death.

Key Points to Remember

• Heat exhaustion is a serious condition that can progress to life-threatening heatstroke if untreated.
• Move the person to a cool place, help them rehydrate, and cool their body. Call 999 if symptoms worsen or if heatstroke is suspected.
• For heatstroke, act immediately by calling for emergency help, cooling the person rapidly, and monitoring their condition closely.