Like it or not (and let’s be honest, most of us are big fans), summer is here. Garden chairs are dusted off, BBQs wheeled out of hibernation, and sunglasses finally escape their top-shelf exile. For many of us – myself included – it’s the unofficial start of road trips, picnics, beach days, and routinely underestimating how long I can bask in the sun without turning into a lobster.
But while we’re revelling in warm weather and outdoor exploits, there’s peril lurking in the background: heatstroke in dogs. Every summer I see more cases than I’d like, and not all of these cases have happy endings – and I’m just one vet.
Along with a team at Nottingham Trent University, the Royal Veterinary College has found that the vast majority of cases of heatstroke in dogs (74% to be exact) were actually a direct result of pet owners exercising their pets. Only 13% of cases were due to hot weather alone, and 5% of cases occurred during travel or where dogs were left in vehicles [1].
You know what this means?
This means a staggering three quarters of all of the cases of canine heatstroke in the UK are entirely preventablethrough increasing awareness and education. Which brings me to this article. This summer, let’s do things differently.
What is Heatstroke in Dogs?
Heatstroke is a serious, life-threatening condition that develops when a dog’s body temperature climbs to dangerous levels. It’s most often triggered by exposure to hot or poorly ventilated environments, exercise, or a combination of the two. Sadly, studies suggest that around 14% of dogs who suffer from heatstroke won’t survive [1].
It’s important to understand that heatstroke isn’t the same as hyperthermia, although the two are often confused online. Hyperthermia is simply an elevated body temperature, which might result from a fever (caused by infection), or from heatstroke. The key difference lies in the cause.
If your dog’s temperature hits 40°C (104°F) or higher, that’s a huge red flag, and you need to call your vet immediately. Keeping a thermometer in your pet first aid kit is a smart move, as is familiarising yourself with how to use it properly. The context often tells the story: if the high temperature follows a car ride or chasing a ball in the heat, there’s a good chance heatstroke is to blame.
Signs of Heat Stroke in Dogs
Early signs to look out for include:
- Constant or frequent panting
- Searching for a cool spot
- Lying down in a spread-eagle body position
- Loss of appetite
If you notice any of the above signs, please follow the first aid advice below and also contact a The Net Vet vet without delay so that we can assess your pet remotely and determine the best course of action.
If your dog isn’t able to cool their core body temperature, then a more severe heat stroke may develop, and the following might be seen:
- Bright red gums
- Glazed, glassy eyes
- Vomiting
- Diarrhea, which can contain blood
- Seizure or collapse
- Small red or purple spots on the skin or gums
- Difficulty breathing
- Lethargy and/or confusion
If you are seeing a combination of signs that suggest severe heat stroke then it is best to contact your local emergency vet without delay while also carrying out the first aid measures detailed at the end of this article.
Heatstroke and Dehydration in Dogs
Heat stroke often goes hand-in-hand with dehydration in dogs. Every pet owner should be aware of the tell-tale signs of dehydration. Mild dehydration doesn’t have visible signs, so you won’t be able to notice it, although your dog may seem thirstier than usual.
Moderate dehydration occurs once your dog has lost between 5-9% of their body’s normal total water volume. At this point, you’ll notice:
Heatstroke and dehydration often show up as a dangerous duo in dogs. It’s important for every dog owner to know what to look for when it comes to dehydration. Early dehydration is sneaky and doesn’t produce obvious symptoms, though your dog might seem suddenly thirstier than usual.
When dehydration progresses and your dog loses 5-9% of their normal body water, clearer signs start to appear. At this stage, you might see:
- Lethargy
- Gums that feel dry and tacky to the touch
- A reduced capillary refill time (CRT). Here’s me demonstrating how to check your dog’s CRT yourself at home in under 60 seconds: https://www.youtube.com/watch?v=WLyQLId-kJE
- In a well hydrated dog, the CRT is less than two seconds, rising to 2 seconds with moderate dehydration.
If severe dehydration develops you may see:
- CRT of 2+ seconds
- Sunken eyes
- Skin that doesn’t spring back when tented
- Extreme lethargy
Severe dehydration can be fatal within minutes to hours. For this reason it must be rapidly addressed with emergency veterinary care.
How to Stop Heatstroke Before It Starts
Most cases of canine heatstroke during the UK summer months are entirely avoidable. A few sensible steps can go a long way in keeping your dog safe when the temperature rises.
- Check the weather before heading out. Dogs with short muzzles (like pugs and bulldogs), those carrying extra weight, or breeds adapted to cold climates (Siberian huskies and Alaskan Malamutes, for example) can struggle with heat – even on days that don’t feel especially warm to us.
- Make sure your dog always has a cool, shaded, and well-ventilated spot to retreat to.
- Keep their water bowl topped up. Dehydration creeps in faster than you’d think.
- Setting up a fan can be a simple way to help your dog cool off, especially indoors.
- Learn to recognise the early signs of overheating and take them seriously. If your dog is panting heavily, it’s time to pause the walk and find some shade.
First Aid for Heatstroke in Dogs
- In the case of signs of severe heat stroke, put first aid first and transportation second. Put your local emergency vet on speaker so they know you’re coming while you work.
- Get them out of the heat. Shift your dog to a shaded or indoor spot with strong airflow: a fan, open windows, anything that moves air.
- Offer small sips of cool water. Let your dog drink, but don’t force it down.
- Pour cool (but not cold) water over the chest, belly, and inner thighs. Skip the head to avoid aspiration. Avoid the ancient wisdom of placing cold, soaked towels over your dog as these actually trap heat and can make things worse.
- Boost evaporation. Aim a fan at the damp areas. Evaporative cooling drops core temperature.
- Monitor temperature if you can. Rectal thermometer only: once the dog hits 39.5 °C (103 °F), stop active cooling to prevent overshoot.
- Get to your local emergency hospital or clinic fast. Use an air-conditioned vehicle. No AC? Ring a taxi or rideshare and make it clear that you’re transporting a dog with heat stroke and that a cool car is absolutely critical.
By taking simple preventative measures and being vigilant for early signs, we can significantly reduce the risk of heatstroke in our dogs. Remember, rapid identification of the signs of heatstroke and swift action can save lives. Let’s ensure that summer remains a joyful season for both us and our pets.