The warm, sunny weather of summer is welcomed by most of us, but it isn’t always good news for pets. Heat stress in dogs is a serious issue, and owners need to be aware of the signs of a dog overheating, as well as how to keep their dogs cool and what to do should they become overheated.
As a vet in practice, every year I witness dogs dying of heat stroke: when this happens, the grief of the owner at losing their pet is compounded by their realisation that if they had known how to stop a dog overheating, they could have saved their pet’s life.
One of the most important summer skills for a pet owner is to know how to keep your dog cool in the summer heat.
Dogs have an inherent susceptibility to heat stroke. A survey of vets found that 48% of vet clinics had to treat dogs for heat stroke during the summer months.
Given that this is a preventable problem, the figure is astonishingly high. So what are people doing wrong, and how can they avoid heat stress in dogs?
Why dogs are prone to heat stress
Dogs deal with excessive environmental heat very differently to humans.
We are able to consciously seek out cooler areas, opening doors and moving to different parts of the house if we feel uncomfortable. In contrast, dogs must stay where they are placed by humans, so if they are in an area that is too hot, they cannot choose to move elsewhere
We can remove items of clothing if we are too hot: dogs are stuck in their fur coats
We exude sweat from all over our bodies, losing heat from our skin as this fine film of moisture evaporates. Dogs do not sweat in this way
In dogs, the heat losing mechanism is primarily by panting. The tongue swells up, filling with warm blood, and air is forced over rapidly over the tongue. The dog pants, with fast, shallow breathing at the natural resonant frequency of the airways.
Warm moisture evaporates from the tongue and is exhaled into the environment while the cooled blood returns from the tongue to the body.
There are two main factors that lead to dogs suffering from heat stroke
They are left in warm, enclosed environments which they cannot leave, so that they are unable to lose heat by panting
They do not have enough water to replace the high levels of fluid lost during panting, leading to dehydration and diminished ability to lose heat
Situations leading to heat stroke in dogs
Cars are still the most likely location for heat stroke in dogs. The enclosed area, with limited air space, surrounded by heat-intensifying glass, creates a dangerous combination of factors. Everyone knows that you must never leave dogs unattended in cars, but even if you are present with dogs, they can still overheat.
If travelling with dogs, use air conditioning to keep the car cool (here's how best to do this). Provide plenty of fresh water, either using a non-spill water bowl or by stopping regularly to offer a drink. When travelling, it’s worth taking regular travel breaks, taking the dog for short walks in the shade to ensure that they are comfortable.
The second, less well recognised situation that leads to heat stroke in dogs happens when they are taken for vigorous exercise in the heat of the day. Dogs love to exercise, and the vigorous muscle activity involved generates a high amount of heat inside the body.
When this is added to the heat entering a dog’s body by radiation from sunshine, the result can be a rapidly increasing core body temperature. Affected dogs may collapse, panting, in the middle of a walk, with the dog flopping down as if exhausted.
Typically, the dog will refuse to get up and walk when their owner calls them, and they may even need to be carried back from the walk.
Owners are usually unaware that their dog is suffering from overheating, and it’s only when the dog’s temperature is taken at the vet that this becomes apparent. The consequences of this delayed treatment can be life threatening.
Some dogs are more prone to heat stroke than others:
brachycephalic dogs (their breathing is already restricted, even without the stress of overheating)
obese dogs (they have an extra layer of insulation in the form of fat)
dogs suffering from laryngeal paralysis (their breathing passages are narrower than normal, making them unable to pant like a normal dog)
dogs with dark coats (solar radiation is absorbed into the body rather than being reflected)
Animals of these types deserve special protection from potentially overheating situations because they are less able to cool themselves down.
How to prevent heat stroke
Heat stroke is an emergency, with the potential for serious illness and death. The best approach is to prevent heat stroke by taking some simple steps.
Avoid activities, such as those listed above, that are linked to dogs getting overheated.
Never exercise your pet in the full heat of the day in summertime: instead take your dog for walks in the early morning or evening.
Provide fresh water for your pet at all times, taking a portable water supply on walks with you during the summer months.
If you notice your pet panting more than normal, move them into a cooler, shady area: even if they seem happy lying in full sunlight.
Dogs with long, dense coats may benefit from having their fur clipped short
Give less food in hot weather, and feed in the early morning or evening (the process of digestion can generate a surprising amount of body heat.)
How to treat a dog with heat stroke
It can be difficult to recognise that a dog has heat stroke without taking their temperature. But if a previously healthy dog flops down to the ground, continually panting, in the full heat of the day, then heat stroke is high on the list of possibilities. If the dogs has been in an enclosed space (like a car) or has been exercising heavily in a warm environment, then the diagnosis is even more likely.
Urgent treatment is essential in such cases: the general principle is to cool the dog down without causing over-chilling.
Application of cool water to the body
Cool water can be poured over the animal: a sponge may help to obtain maximal drenching and cooling from a bucket if a continual water supply such as a hose is not available. The application of cold, wet towels is also helpful. Packs of frozen vegetables can also be applied to the body and head can provide additional cooling.
Submersion in water
If you are close to a body water such as a shallow river or lake, then carry the animal to a safe place where they can be gently immersed. Do not use water more than a foot or so in depth: you need to be able to stand securely beside your pet, not allowing their head to go beneath the surface. If you are at home, use your bathtub to allow immersion.
Don’t overchill an overheated dog
There is a serious risk of over-chilling an animal: once your dog stops panting and begins to walk around normally, stop the cooling process.
Provide plenty of cool drinking water
Overheated dogs need to be cooled down on the inside too, so offer plenty of fresh, cool water, and keep offering it until you are certain that the dog has drunk to their fill.
Take your dog to the vet
While first aid can be essential, vets have additional means of cooling overheated dogs, including cold intravenous infusions, and they are able to monitor the core temperature of the dog with thermometers.
Heat stroke can cause serious damage to internal organs, with signs of this damage not being apparent for twenty four hours or more. Early treatment, including rehydration with intravenous fluids, is an important part of care.
For these reasons, any dogs suspected of suffering from heat stress should be taken to the vet for monitoring and further treatment as needed.
Don’t let the summer sunshine and heat spoil your summer: make sure that you stop your pet dogs from turning into hot dogs.