Dogs living in London are more likely to suffer from heatstroke than elsewhere in the UK, and owners are being warned to be vigilant about symptoms as summer approaches.
A new study found that dogs in the capital had up to double the chance of getting heat-related illness than in some other regions.
Heatstroke, also called heat-related illness, is potentially fatal and experts suggest it could become more common as global temperatures rise.
As summer approaches, owners are being warned to look out for early signs of heatstroke.
These include excessive panting, red or darkened gums and tongue, confusion and unsteadiness leading to collapse, diarrhoea, vomiting and even seizure leading to coma.
If the dog is not cooled immediately, owners should contact a vet.
The study suggests flats and terraced housing are associated with an increased risk of overheating, and that a greater percentage of cases in London were triggered by confinement in a hot building.
Researchers found that across the UK, older and heavier dogs were most at risk of developing severe heatstroke.
When it came to the risk of dying, older dogs and flat-faced breeds such as pugs and bulldogs were at most risk.
The Nottingham Trent University and the Royal Veterinary College researchers were surprised to find that the average temperature in which dogs became ill from heatstroke was 16.9C.
This is much lower than previously thought, and busts the myth about dogs only becoming high risk for heatstroke in scorching temperatures, the scientists say.
Emily Hall, a veterinary surgeon at the Royal Veterinary College and main author of the paper, said: “As global temperatures continue to rise, better understanding of the combined risk factors for heatstroke will support more targeted owner education to improve canine welfare.
“Whilst the most common trigger overall was exercise, our findings highlight the increased risk of severe and fatal heatstroke associated when dogs cannot escape the heat source or have reduced capacity to thermoregulate, such as older dogs and brachycephalic breeds.
“Both flats and terraced housing are generally located within the warmest parts of cities and are associated with an increased risk of overheating.
“Whilst it does not explain all the additional heatstroke events in London, a significantly greater percentage of cases in London were triggered by confinement in a hot building compared to the rest of the UK.”
The researchers investigated risk factors for heatstroke by analysing 2016 vet records of more than 900,000 UK dogs from the VetCompass programme at the Royal Veterinary College.
They found that during the single year of the study, 390 dogs needed vet care for heatstroke, including 72 in London.
The risk for heatstroke for dogs living in London was double that found in Yorkshire, and almost double that in the North West and East of England.
Looking at the specific triggers behind heatstroke events between 2016 and 2018, the researchers found exertion, or exercise, was responsible for 68% of heatstroke cases in London and hot weather 14%.
According to the study, dogs that were confined to a hot building accounted for 8% of cases in London, which was more than double that of the wider UK figure of 3%.
Researchers suggest this could be due to a higher proportion of flats than in rural locations, and because the ambient temperature in cities such as London can be about 5C warmer than in the countryside.
Just 1% of heatstroke cases in London were linked to a dog being left in a hot car, compared to 6% nationally.
The team is urging owners to remember that while dogs do die in hot cars, far more develop heatstroke on hot walks, and for dogs that are older, or flat-faced, even mild heat can be deadly.
Heavier dogs which weighed between 40-50kg were at greater risk of developing severe heatstroke, the study also found.
Dr Dan O’Neill, associate professor companion animal epidemiology at the Royal Veterinary College and co-author of the paper, said: “These results emphasise the double-whammy risk of heatstroke that dogs face in built-up areas: rising global temperatures everywhere combined with the concrete cooking effects from living in city environments.
“Awareness of these extra risks can help owners take steps to protect their dogs, especially as we approach the summer months.”
The findings are published in the journal Veterinary Sciences.