Heat, excessive sweating, and the resulting loss of fluids and salts can lead to various degrees of heat-related illnesses. This page provides information on their symptoms and treatment.
Heat stress can also worsen the symptoms of many chronic illnesses. In addition, several diseases and the medications used to treat them may impair the body’s ability to adapt to heat and increase the risk of heat illnesses.
Heat Rash
Excessive sweating may cause a heat rash characterised by small red bumps on the face, neck, chest, under the breasts, groin area, or scrotum. Heat rash is more common in young children.
No special treatment is needed, but the affected area should be kept dry. Antihistamine or antiseptic creams may provide relief.
Heat oedema
Heat may cause swelling in the lower limbs, especially around the ankles.
Swelling usually eases as the body adapts to the heat or when temperatures drop, and it typically requires no specific treatment. If the person uses diuretics, swelling may also be related to an underlying illness. In such cases, medication should be discussed with a physician.
Heat cramps
After physical exertion, muscle cramps may occur due to fatigue, dehydration, and salt depletion. Cramps usually affect the lower limbs but may also occur in the arms or abdominal muscles.
Cramps can be relieved by resting in a cool place, drinking fluids and electrolytes, and gently massaging or stretching the affected muscles. If cramps last for more than an hour, contact healthcare services.
Heat syncope
Heat-induced drops in blood pressure can cause sudden dizziness or fainting.
Rest in a cool place with legs elevated and drink water. If the condition does not improve, contact healthcare services.
Sunstroke
Sunstroke is caused by direct heat radiation to the head and irritation of the central nervous system. Young children are particularly susceptible. Symptoms include headache, nausea, dizziness, and irritability.
Move to a shaded and cool place to rest. The head should be elevated, and a cold compress can be placed on the forehead. If the general condition worsens, contact healthcare services.
Heat Exhaustion
Heat exhaustion develops gradually due to fluid and salt depletion. Possible symptoms include intense thirst, heavy sweating or cool and clammy skin, weakness, headache, dizziness, irritability, and nausea.
Mild heat exhaustion usually improves by drinking water and resting in a cool place. Clothing should be loosened or removed, and cooling can be supported by wetting the skin with cool water and fanning, or cold packs.
If symptoms are severe or do not improve, contact healthcare services. Contact your local health centre or the national Medical Helpline (116 117) by phone. Call the emergency number (112) only in urgent emergencies. If the person is confused or their level of consciousness is impaired, call emergency services immediately.
Heat Stroke
Heat exhaustion can progress into life-threatening heat stroke. During intense physical exertion, heat stroke may also develop very suddenly.
In heat stroke, the body can no longer dissipate heat, sweating stops, and body temperature rises above 40 °C. Symptoms may include hot and dry skin, weakness, headache, nausea, loss of balance, difficulty breathing, rapid and weak pulse, abnormal behaviour or confusion, seizures, and sudden loss of consciousness.
Heat stroke is a medical emergency. Call the emergency number 112 immediately.
While waiting for the ambulance:
- Move the person to a shaded and cool place, remove clothing, and begin cooling the body immediately.
- Cool the body by spraying or pouring cool water onto the skin and fanning, or by placing cold packs on the neck, armpits, and groin.
- If conscious, place the person in a semi-sitting position or lying down with legs slightly elevated; if unconscious, place them in the recovery position.
- Offer cold water or other drinks (not alcohol or caffeinated beverages) if the person is alert enough to drink.
- Do not give fever-reducing medicines, such as paracetamol or aspirin.