Brits are urged to look out for a potentially painful hot weather symptom in the arms and legs that could be a sign of a medical emergency. With the UK experiencing high temperatures this week it is important to be aware of any symptoms of heat stroke.

Temperatures have seen highs of 29C in England this week, marking the hottest April day in more than 70 years.

Camden Square in London saw temperatures reach a scorching 29.4C, the hottest recorded April day since 1949.

Nicola Maxey, press officer at the Met Office told The Mirror, said: “As high pressure continues to dominate the UK weather we will see the temperatures building day on day through the week with Thursday seeing the peak of the heat with 29C or even a chance we could see 30C.

“Friday temperatures will start to dip across much of the UK as the high pressure starts to pull away.”

With this in mind, it’s important to be aware of some of the risks that come with hot weather. The NHS explains that heat exhaustion can develop into heatstroke if not treated quickly.

“Heat exhaustion does not usually need emergency medical help if you can cool down within 30 minutes,” the health body said. “If it turns into heatstroke, it needs to be treated as an emergency.”

A lesser-known sign of heat exhaustion includes cramps in the arms and legs. You may also feel cramps in your tummy.

Other symptoms to look for are:

• Tiredness
• Dizziness
• Headache
• Feeling sick or being sick
• Excessive sweating and skin becoming pale and clammy or getting a heat rash, but a change in skin colour can be harder to see on brown and black skin
• Fast breathing or heartbeat
• A high temperature
• Being very thirsty
• Weakness

The NHS said: “The symptoms of heat exhaustion are often the same in adults and children, although children may become irritable too.”

What to do if someone has symptoms

If someone you know is showing signs of heat exhaustion, they must be cooled down and given fluids. The NHS recommends you follow these four steps:

• Move them to a cool place
• Remove all unnecessary clothing like a jacket or socks
• Get them to drink a sports or rehydration drink, or cool water
• Cool their skin – spray or sponge them with cool water and fan them. Cold packs, wrapped in a cloth and put under the armpits or on the neck are good too

You should stay with them until they’re better, which should take 30 minutes. However, if this has not worked you may need to call 999.

Find out about the symptoms you need to watch out for and get health advice with our free health newsletter from the Daily Express

The NHS says you should call 999 or go to A&E if you or someone else have signs of heatstroke, including:

• Still unwell after 30 minutes of resting in a cool place, being cooled and drinking fluids
• A very high temperature
• Hot skin that’s not sweating and might look red (this can be harder to see on brown and black skin)
• A fast heartbeat
• Fast breathing or shortness of breath
• Confusion and lack of coordination
• A seizure or fit
• Loss of consciousness

You should put the person in the recovery position if they lose consciousness while you’re waiting for help.