UK heatwave: what is heatstroke and how can you treat and prevent it?

A four-day health warning for most of England came into force on Monday (June 24), with London set for temperatures of up to 29C this week.

The mercury could soar to as high as 30C in other parts of the country.

While many welcome some long-awaited sunshine and high temperatures, those exposed to such conditions for prolonged periods are advised to be careful.

A soldier collapsed on The Mall amid the soaring temperatures on Monday.

Here’s all you need to know about heatstroke, which can result from being in the sun for too long without protection.

What is heatstroke?

Heatstroke, also called sunstroke, is a severe and potentially life-threatening condition caused by the body's inability to regulate its temperature in extremely hot environments.

It occurs when the body’s temperature rises to 104F (40C) or higher, leading to systemic effects. Heatstroke can damage the brain, heart, kidneys, and muscles, and without prompt treatment, it can be fatal.

What are the symptoms of heatstroke?

Heatstroke is a serious condition requiring immediate medical attention. Here are some signs to watch for:

• High body temperature: The main sign of heatstroke is a core body temperature of 104F (40C) or higher, measured with a rectal thermometer.
• Altered mental state: Confusion, agitation, slurred speech, irritability, delirium, seizures, and coma can all be signs of heatstroke.
• Changes in Sweating: The skin will feel hot and dry in classic heatstroke. However, the skin may be moist or slightly sweaty in exertion-related heatstroke,

Here are some other symptoms to be aware of:

• Nausea and vomiting.
• Flushed skin.
• Dizziness.
• Headache.
• Muscle cramps or weakness.
• Rapid breathing or heartbeat.

How is heatstroke treated?

Heatstroke is a medical emergency, so while you wait for help to arrive, here are some first-aid steps you can take to cool the person down:

1. Move them to a cool place: Get them out of direct sunlight and into an air-conditioned space if possible. If not, find a shady area.

2. Remove excess clothing: Loosen belts and tight clothing to improve air circulation.

3. Cool the person down:

   Spray or sponge their skin with cool water (not ice cold).

   • Fan them while misting them with water to speed up evaporation.
   • If available, immerse them in a cool bath or shower.
   • Apply ice packs to the groin, neck, and armpits — areas with large blood vessels close to the skin.

4. Offer fluids: If the person is conscious, offer them cool fluids to drink, but avoid alcohol or caffeine. Small sips of sports drinks or electrolyte solutions can help replenish salts and fluids lost through sweating.

Important things to avoid:

• Do not give them medication: Unless instructed by emergency personnel, avoid giving them any medications, including aspirin or ibuprofen.
• Do not force fluids: If they vomit or are unconscious, do not force fluids down their throat.

Remember, these are just first-aid measures to buy time until medical help arrives. Call emergency services immediately if you suspect someone is suffering from heatstroke.

How can you prevent heatstroke?

The good news is that heatstroke is largely preventable by following some simple precautions:

• Stay hydrated: Drink plenty of fluids throughout the day, even if you don't feel thirsty. Water is ideal, but sports drinks can be helpful if you're sweating a lot. Avoid sugary drinks and excessive alcohol, as they can dehydrate you.

• Dress for the weather: Wear loose-fitting, lightweight, light-coloured clothing, allowing sweat to evaporate. Avoid tight clothing and dark colors that absorb heat.

• Schedule activities: Avoid strenuous activity during the hottest part of the day, typically between 11am and 3pm. If you must be outside, take frequent breaks in air-conditioned or shaded areas.

• Acclimatise yourself: If you're not used to hot weather, it takes time for your body to adjust. Gradually increase the intensity and duration of your outdoor activities over several days or weeks.

• Sun protection: Protect yourself from sunburn with a wide-brimmed hat, sunglasses, and broad-spectrum sunscreen with SPF 30 or higher. Reapply sunscreen every two hours, or more often if sweating or swimming.

• Air conditioning: If your home isn't air-conditioned, spend time in public spaces with air conditioning during the hottest part of the day, such as libraries, shopping malls, or community centres.

• Be mindful of medications: Certain medications can increase your risk of heatstroke. Talk to your doctor about any potential risks associated with them during hot weather.

• Never leave people or pets in parked cars: Parked cars heat up quickly, even on seemingly mild days. This is especially dangerous for children and pets who can't regulate their body temperature as effectively as adults.

By following these tips, you can significantly reduce your risk of heatstroke and enjoy the warm weather safely.