Heatstroke in dogs

isolated dog


  • Heatstroke in dogs is a very serious illness that can be fatal.
  • Overheating during exercise is by far the most common cause of heatstroke in dogs, but in some circumstances, it can even develop when a dog simply sits in the heat for too long.
  • Any dog can develop heatstroke, but flat-faced dogs are most at risk because they struggle to cool themselves down easily.
  • If your dog has symptoms of heatstroke, give them first aid and contact your vet straight away.
  • As the world gets hotter, and we experience more unpredictable weather, we need to take every precaution to keep our pets safe on hot days.

What is heatstroke?

Dog playing in paddling pool in summer

Heatstroke is a serious illness that develops when a dog gets too hot and is unable lower their temperature. A dog’s normal body temperature is around 38.6°C (101.5°F). Left untreated, heatstroke can lead to seizures, organ failure and even death. Some of the most common triggers for heatstroke include:

  • Overheating during exercise - accounts for 74% of cases
  • Being outside in hot weather (even just sitting still) - accounts for 12.9% of cases
  • Being trapped in a hot car - accounts for 5.2% of cases

Any dog can develop heatstroke, but overweight, young, elderly, flat-faced, giant-breed, and thick-coated dogs are particularly at risk, even from just sitting out in hot weather.

Signs of heatstroke in dogs

Signs of heatstroke in dogs include:

  • Panting
  • Drooling and foaming at the mouth
  • Bright red gums
  • Shaking
  • Weakness and collapse
  • Confusion
  • Vomiting and diarrhoea (sometimes containing blood)
  • Seizures
  • Death


First aid

It’s important to act fast if you notice your dog developing symptoms of heatstroke.

  1. Keep them calm and still
  2. Take them indoors or into a shady area
  3. Give them a drink of cold water (not ice, or icy water)
  4. Contact your vet
  5. Make sure they have plenty of air flowing around them
  6. Put them on top of a wet towel
  7. Using cool (not icy) water* to slowly wet the top of their head, feet, ears and fur
  8. Once they seem a bit cooler, you can start to pour cool water over their body (be careful they don’t inhale any)
  9. If possible, continue cooling your dog on the way to your vet

*Never use ice or very cold water – this can cause shock.


Your vet will examine your dog and try to reduce their temperature by carefully using fans, cool water, and a fluid drip if necessary. Your dog may also need medication if they start fitting because of heatstroke. Your dog will be monitored very closely until they have recovered, and may require blood tests if your vet is concerned about their vital organs.

Your dog will then be sent home for monitoring once they are stable, but you will need to keep a close eye on them for 24-48 hours and let your vet know if they deteriorate or develop any symptoms such as confusion, refusing food, vomiting, or diarrhoea.


If your dog has a mild case of heatstroke, and they receive treatment quickly, they are likely to make a full recovery. However, if they become seriously unwell, or their treatment is delayed, they could suffer organ damage or even die.

When to contact your vet

Contact your vet as soon as you notice symptoms of heatstroke. The faster treatment is started, the better your dog’s outlook. It’s also important to start first aid, but remember, never to use very cold water or ice while cooling your dog (it could cause them to go into shock).

Preventing heatstroke in dogs

Dog drinking water from a water bottle in summer

It’s vitally important to protect your dog from heatstroke, especially if they are flat-faced, overweight, or have a thick coat. There are some simple things that you can do to reduce the chance of a problem, such as:

  • Avoid walking your dog during the hottest part of the day; instead, take them out in the morning or evening when it is cooler. Avoid exercise completely on warm days if they are unfit, elderly, young, overweight, unwell, or have breathing difficulties.
  • Make sure your dog always has access to shade and water, especially if you are sitting in a sunny area with them. It’s a good idea to take a travel bottle and bowl with you on walks.
  • Use a harness instead of a collar, especially if your dog is brachycephalic (flat-faced). Collars can put pressure on the neck and make it difficult for a dog to breathe and cool down.
  • Never walk your dog on a surface that is too warm for you to place your hand on it comfortably for 7 seconds. Sand, artificial grass and tarmac get especially hot.
  • Never leave your dog in a hot car on a warm day, not even for a few minutes or with the window open. Cars get hot very quickly, which can be fatal for a dog left trapped inside.
  • Avoid travelling with your dog in a car when it’s hot. If travel is absolutely necessary, make sure they have access to drinking water, plenty of shade, and air flowing around them. Cooling mats can be useful when travelling on warm days.
  • Keep your dog a healthy weight; overweight dogs find it more difficult to cool themselves down.
  • Consider having your dog clipped in the warmer months if they have a heavy coat.

Heatstroke in brachycephalic dogs

Dog’s noses play a very important part in keeping them cool by releasing excess body heat into the air they breathe out. Brachycephalic (flat-faced) dogs struggle to release heat this way because of the drastically reduced space they have inside their nose. This puts flat-faced dogs at a very high risk of heatstroke, even on cool days, and especially during exercise and on hot days. Dogs most affected include the Pug, English Bulldog, French Bulldog, Dogue de Bordeaux, Pomeranian, Shih Tzu and Boston Terrier. English Bulldogs are 14 times more likely to develop heatstroke than Labradors, and Pugs are 6 times more likely!


Emergency treatment for a poorly pet can be expensive. Consider insuring your dog as soon as you get them, before any problems start to ensure you have all the support you need to care for them.

Published: June 2021

PetWise Pet Health Hub – brought to you thanks to support from players of People’s Postcode Lottery 

Written by vets and vet nurses. This advice is for UK pets only.

Illustrations by Samantha Elmhurst