Animal welfare experts behind the iconic ‘dogs die in hot cars’ campaign claim exercising dogs on scorching days could be equally fatal for people’s pets.

The British Veterinary Association says four in 10 vets treated at least one animal last summer that had been exercised in the heat.

As June’s heatwave continues, charities fear that some owners may still not appreciate how dangerous taking pets outside in the very warm weather can be – with the RSPCA describing heat exhaustion as a ‘silent killer’.

Esme Wheeler, dog welfare specialist at the charity, said: “Thanks to years of campaigning, public awareness of the dangers of leaving dogs in hot cars is well understood. However, exercising dogs in hot weather can also present a huge risk to our beloved animals and can be just as deadly. This is why every single dog owner needs to be savvy as we enter summer, and be mindful of potential harm caused to dogs by more strenuous or sustained exercise on warmer days.

“Too many times we have seen people out running with their dogs, cycling with their dogs running alongside, or throwing balls for their dogs during hot weather, with beloved pets often left panting heavily and at serious risk of overheating.”

While all breeds and types of dog are at risk those with underlying conditions – especially ones that affect breathing – and older dogs can overheat more easily.

Animals who are overwieght, or which carry thick or double coats, are also at an increased danger as are breeds with large or flat-faces.

There are now plans to extend animal welfare campaigns to warn that dogs can die on hot walks as well as in hot cars using the message ‘If in doubt don’t go out’.

BVA junior vice president Anna Judson said: “Every year, vets see a large number of cases of dogs requiring treatment for heat-related conditions, many of which are a result of being walked or exercised during the hottest parts of the day.

“We would like to see it become the norm that dog owners always err on the side of caution when it comes to hot weather, and instead, walk their pets in the early morning or late dusk when temperatures are cooler.”

Signs of heat related illness in dogs can include:

Excessive panting that doesn’t stop when the dog rests.

Difficulty breathing, especially if there is unusual noise or any blue/grey tinge to gums or tongue.

Unusual tiredness - becoming tired sooner than normal.

Changes in behaviour - lying down more frequently and stumbling.

Less keen to play.

Anyone who notices these signs in their animal should stop them running around, move them to the shade, give them small amounts of cool water, lay them in room-temperature water and gently pour it over them and call the vet immediately for further advice.