Visitors to the coast have been urged to take extra caution over “lethally cold” water amid a nationwide heatwave.

Eastern Daily Press: Hundreds enjoy the sun on Gorleston beach on August 7. PHOTO: Reece HansonHundreds enjoy the sun on Gorleston beach on August 7. PHOTO: Reece Hanson (Image: Archant)

The Royal National Lifeboat Institution (RNLI) has warned that, despite soaring temperatures, the water at Norfolk’s beaches remains cold and could have “potentially deadly effects” due to shock.

They said the sudden cooling of cold water can cause a gasp for breath which could contribute to a feeling of panic and increases the chance of inhaling water.

Eastern Daily Press: RNLI lifeguard supervisor Nick AyersRNLI lifeguard supervisor Nick Ayers (Image: Archant)

It only takes half a pint of sea water to enter the lungs for a fully grown man to start drowning.

Nick Ayers, the RNLI’s water safety lead in the East, said every year there are tragic incidents of lives being lost to cold water shock.

He added: “When we have the rare opportunity to enjoy a really hot weekend it’s easy to forget that the water is still very cold. However, we would remind the public that your split second decision to take the plunge can be a lethal one. Cold water shock can take effect immediately and could cost you your life.

“If you are at the coast or around any other body of water this weekend, please look out for each other, avoid suddenly immersing yourself in cold water and if you do find yourself suddenly in the water, float to live. Take a minute. The initial effects of cold water pass in less than a minute so don’t try to swim straight away. Relax and float on your back to catch your breath. Try to get hold of something that will help you float.

“Keep calm then call for help or swim for safety if you’re able.”

Anything below 15c is defined as cold water and can seriously affect your breathing and movement, while average UK and Ireland sea temperatures are just 12c all year round.

If you do see someone at risk call 999 and ask for the coastguard.