Sun Stroke & Heat Stroke: Symptoms, Treatment, First Aid

Sun stroke — medically called heat stroke — is when the body overheats above 40°C and can no longer cool itself down. The main symptoms are a very high temperature, hot flushed skin, a pounding headache, dizziness, nausea and confusion, and the skin may stop sweating. It is a life-threatening medical emergency: move the person somewhere cool, start cooling them and call 112 in Spain without delay. Below we cover the warning signs, first aid, and how heat stroke differs from milder heat exhaustion.

You'd be forgiven for thinking we should all know better. We're told constantly to wear sun cream, stay hydrated, and avoid the midday sun. But if you're living in or visiting Spain, especially during peak summer, the heat can still catch you off guard. While sunburn is annoying, sunstroke—also known as heatstroke or hyperthermia—is a serious medical condition that can be life-threatening if ignored.

What is Sunstroke?

The medical term for the severe form is heat stroke, a dangerous type of hyperthermia (not to be confused with hypothermia, which means too cold). Hyperthermia means your body temperature has risen too high and can no longer regulate itself. It typically occurs after prolonged exposure to extreme heat, especially under direct sun or in hot, enclosed environments.

Spain’s inland regions such as Andalusia, Extremadura, and Murcia regularly hit 40°C and beyond during summer. And it’s not just dry heat—city breaks, fiestas, and even sitting in the shade with alcohol can contribute to overheating.

How Sunstroke Happens

Your body usually cools itself through sweating. But when temperatures soar and humidity is low, that cooling system can fail. Once your core temperature rises past 38°C–40°C, your body's internal functions begin to break down—potentially resulting in seizures, coma, or death if not treated.

Recognising the Classic Symptoms of Sunstroke

Some signs are widely known, and you should act immediately if you notice them:

• Body temperature over 38–40°C
• Red or flushed skin
• Dizziness or fainting
• Nausea or vomiting
• Headache
• Rapid pulse
• Hot, dry skin (due to lack of sweating)

As the temperature rises, blood pressure can drop, causing the heart to race and the skin to flush. The person may feel faint, disoriented, or extremely weak.

Dehydration and salt loss often go hand in hand with sunstroke, which makes it harder for the body to regulate itself.

Heat Exhaustion vs Heat Stroke: Know the Difference

Heat exhaustion is the warning stage that comes before heat stroke. Spotting it early and cooling down usually stops it becoming an emergency.

Heat exhaustion (serious, but not usually an emergency) – the person feels unwell but is still alert:

• Heavy sweating with cool, pale or clammy skin
• Tiredness, weakness and dizziness
• Headache, nausea and muscle cramps
• A fast, weak pulse and intense thirst

Heat stroke (a medical emergency – call 112) – the body can no longer cool itself:

• A temperature of 40°C or above
• Hot skin that may be dry, or still sweating
• Confusion, slurred speech or loss of consciousness
• Seizures or rapid, shallow breathing

How long does heat exhaustion last? With rest in a cool place and plenty of fluids, most people start to feel better within about 30 minutes, though it can take a day or two to fully recover. If there is no improvement in 30 minutes — or the person becomes confused, stops sweating, or has a temperature of 40°C or more — treat it as heat stroke and call 112 straight away.

7 Strange Heatstroke Symptoms Expats Often Miss

Some symptoms aren’t so obvious—especially in dry Spanish heat that tricks you into thinking you're fine.

• Goosebumps in the heat: A sign your body’s cooling mechanism is shutting down.
• Sudden irritability or rage: Neurological distress can show up as aggression or mood swings.
• Slurred speech: Often mistaken for drunkenness but actually a sign your brain is overheating.
• Nausea with no sweat: Vomiting without sweating is particularly dangerous—it means cooling has failed.
• Weak pulse or clammy skin: Not all victims look flushed. Some go pale or develop a thready pulse.
• Hallucinations or mental confusion: Seeing things, disorientation, or memory gaps are emergency signs.
• Persistent cramps: If they don’t stop, it’s likely the muscles are overheating or electrolyte-depleted.

Struggling to stay cool at night? That alone could increase your baseline risk the next day.

Immediate First Aid for Sunstroke

Move the person to a cool, shaded or air-conditioned area immediately. Loosen or remove clothing. Give them cool water—not ice-cold—and encourage small sips if they’re conscious.

If you have access to a bath, soaking them in cool water is better than applying cold towels. Cloths warm up fast and can trap heat. Use water directly on the skin or apply compresses to the neck, groin, and armpits for faster relief.

Hydration is critical. If available, something salty (like crackers) can help replenish electrolytes lost during overheating.

When to Seek Medical Attention

If the patient:

• Still has a temperature over 40°C after 30 minutes
• Stops sweating
• Becomes unconscious, confused, or has a seizure
• Has shortness of breath or a dangerously weak pulse

Call emergency services (112 in Spain) immediately. Heatstroke is not something to wait out. It can progress rapidly and damage internal organs if untreated.

Prevention: Don’t Wait for Symptoms

Protect yourself before you ever feel unwell:

• Drink water regularly—even if you’re not thirsty
• Wear loose, light-coloured clothes
• Use fans or air-conditioning at home or in hotels
• Limit alcohol and caffeine
• Rest indoors from 1–5pm (embrace the Spanish siesta!)

Also be mindful of medications that may impair sweating or hydration. If in doubt, ask your pharmacist.

Final Tip for Expats

If you’re adjusting to your first Spanish summer or living far from a hospital, don’t take risks. Learn the signs. React early. And if you’re unsure whether it’s sunstroke, assume the worst—it’s better to overreact than under-treat.

Need private medical insurance in Spain with fast access to emergency care?

Get peace of mind with private medical insurance in Spain with emergency treatment through Sanitas. Plans are designed for expats and include digital doctor access, urgent hospital care, and no waiting lists. Don’t leave your health to chance—especially in the heat.

More summer safety tips

• Eye Health: Protecting The Eyes From Sun Damage
• Tips To Help You Protect Your Skin From The Spanish Summer Sun
• 12 Easy Ways To Keep Cool And Get A Good Night's Sleep

Getting through the Spanish summer? Read our guide to summer health risks in Spain in the Health Library.