Heat exhaustion first aid

Overview

Heat exhaustion is a condition that happens when your body gets too hot and cannot cool down properly. It is less serious than heatstroke but still needs quick action. If not treated, it can turn into heatstroke, which is life-threatening.

Yes, heat exhaustion is common, especially during heatwaves or when doing strenuous activity in hot conditions.

Anyone can get heat exhaustion, but it is more likely in infants, young children, older adults, people with chronic health conditions like heart disease, and those who work or exercise outdoors.

Symptoms

Common symptoms

• Heavy sweating
• Pale, moist, cool skin
• Dizziness or lightheadedness
• Headache
• Nausea or vomiting
• Muscle cramps
• Fast, weak pulse
• Feeling tired or weak
• Body temperature over 38°C (100.4°F) but below 40°C (104°F)

Symptoms in children

• Irritability or fussiness
• Extreme tiredness (lethargy)
• Flushed, red skin
• Rapid breathing
• Fatigue and weakness

Symptoms in older adults

• Confusion or disorientation
• Weakness or fainting
• Low blood pressure
• Dry mouth or sticky saliva
• Headache or dizziness

Causes

Main causes

• Strenuous physical activity in hot weather
• Prolonged exposure to high temperatures, especially with high humidity
• Not drinking enough fluids (dehydration)
• Wearing heavy or dark clothing that traps heat

Risk factors

• Being very young or elderly
• Having a chronic illness like diabetes, heart disease, or obesity
• Taking certain medications (for example, diuretics or blood pressure drugs)
• Drinking alcohol before or during heat exposure
• Not being used to hot weather (poor acclimatization)

When to see a doctor

See a doctor urgently if:

• If confusion, high fever (above 40°C), or no sweating even when hot
• If you cannot keep fluids down due to vomiting
• If symptoms get worse despite first aid

Book a routine appointment if:

• If you have mild symptoms like headache or fatigue that do not go away after resting in a cool place
• If you have muscle cramps that persist after drinking water

Diagnosis

A doctor will ask about your recent activity and symptoms. They will check your temperature, heart rate, and blood pressure.

Tests that may be done

• Temperature measurement with a thermometer
• Blood tests to check electrolyte levels
• Urine tests to check for dehydration

What to expect at your appointment

The doctor will likely take your temperature with a special oral or ear thermometer. They may also check your pulse and blood pressure. In some cases, they may order blood or urine tests to see how dehydrated you are.

Treatment

The main treatment for heat exhaustion is to cool your body down and rehydrate. First aid should begin immediately. For more severe cases, a doctor may give fluids through a vein (IV) and monitor you closely.

Self-care at home

• Move to a cool, shady, or air-conditioned place immediately
• Lie down and elevate your feet if you feel faint
• Remove extra clothing, including socks and shoes
• Cool your body with a spray of cool water, a cool bath, or cold packs on your neck, armpits, and groin
• Fan your skin to help sweating and cooling
• Drink or sip cool water – about one cup every 15 minutes – or a sports drink if you have been exercising
• Rest until you feel better – do not return to heat or exercise the same day

Medical treatments

If self-care does not help enough, a doctor may start IV (intravenous) fluids to quickly replace lost fluids and electrolytes. They may also use cooling blankets or other measures to lower body temperature. In severe cases, you might need to stay in the hospital for observation.

Living with this condition

If you have had heat exhaustion, your body may be more sensitive to heat for a few days. Take it easy, stay in cool places, and drink plenty of fluids. Avoid strenuous activity in heat until you feel fully recovered.

Lifestyle tips

• Wear light, loose, and light-colored clothing in hot weather
• Take frequent breaks in the shade or air conditioning when outdoors
• Avoid the hottest part of the day (usually 11 a.m. to 3 p.m.)
• Never leave children, elderly people, or pets in a parked car

Diet and exercise

Eat light, cool foods like salads and fruit. Drink water regularly – don't wait until you are thirsty. Avoid alcohol, caffeine, and heavy meals that can increase body heat. For exercise, do it in the early morning or evening when it is cooler, and take water breaks every 15 to 20 minutes.

Mental health and emotional wellbeing

Heat exhaustion can be frightening, especially if you felt confused or dizzy. It is normal to feel a bit anxious about heat after the experience. Try to build confidence by learning prevention tips and staying prepared. If you feel very worried, talk to your doctor.

Prevention

Yes, heat exhaustion can often be prevented. Stay hydrated, avoid overexertion in heat, wear appropriate clothing, and take breaks in cool places. Gradually get used to hot weather over a few days.

Complications

If left untreated

• Heatstroke – a life-threatening condition where the body temperature rises above 40°C (104°F)
• Organ damage, especially to the kidneys, heart, or brain
• Loss of consciousness or coma

Long-term outlook

With prompt and proper first aid, almost everyone recovers fully from heat exhaustion within a few hours to a day. The key is to cool down and rehydrate as soon as you notice symptoms. Heat exhaustion is not usually serious if caught early. If you ever have concerns, see a doctor to be safe.

Find support

External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.