Signs, First Aid and When to Call a Vet
Updated July 2026
This article was originally published in 2016 with a contribution from Dr Oli Robinson of The Finchley Vet.
A lot has changed in heatstroke first-aid advice since then.
I have therefore fully updated this guide using current veterinary guidance while keeping Dr Oli’s original message at its heart:
Heatstroke is an emergency.
Act quickly.
Start cooling.
Contact a vet.
This article is for general information only and does not replace veterinary advice. If you think your dog may have heatstroke, start cooling them immediately and contact a vet as soon as possible.
Heatstroke can happen faster than you think
When we think about heatstroke in dogs, most of us picture a dog trapped in a hot car on a blazing summer day.
That is certainly a serious risk.
But it is not the only way a dog can overheat.
A dog can become dangerously hot after exercise in warm or humid weather. It can happen during a game in the garden, on a long walk, during a run, or even when a determined dog does not know when to stop.
The Royal Veterinary College warns that a dog does not always need to feel extremely hot to develop heatstroke. Excessive exercise and warm, humid or poorly ventilated environments can all cause a dog to overheat.
I see this as a dog walker.
Some dogs will slow themselves down.
Others will happily carry on chasing a ball, sniffing, running or trying to keep up with you long after we should have called it a day.
That is why I change or cancel walks when conditions become unsafe.
You can read more about how I make those decisions in my Extreme Weather Policy
What is heatstroke in dogs?
Dogs do not regulate their body temperature in the same way we do.
Panting is one of the main ways they lose heat.
When a dog produces heat faster than their body can get rid of it, their temperature can continue to rise.
Heatstroke can then become a life-threatening emergency.
It can affect the brain and other organs, and the signs can progress quickly. Veterinary sources, including the PDSA and Royal Veterinary College, advise starting cooling immediately if heatstroke is suspected.
This is not a situation where I would wait half an hour to see whether a dog perks up.
If you are worried, act.
Early signs of heatstroke in dogs
The early signs can sometimes look like a dog who is simply tired after exercise.
That is one reason it is important to know what is normal for your dog.
Signs to watch for can include:
Heavy or excessive panting
Restlessness or agitation
Seeking shade or water
Excessive drooling
Red gums or tongue
Increased heart rate
Vomiting
Diarrhoea
A dog becoming unusually quiet or tired
These signs can progress as a dog becomes more seriously unwell. The RVC lists weakness, confusion, collapse and seizures among the more advanced signs of heatstroke.
Serious signs that need immediate action
Do not wait if your dog is:
Confused
Very weak
Struggling to stand
Collapsing
Having a seizure
Unconscious
Having severe breathing difficulties
Vomiting or passing diarrhoea, particularly if blood is present
The Royal Kennel Club’s current guidance also lists stiffness, an unwillingness to move, loss of coordination and collapse as possible signs of heatstroke.
Start cooling.
Contact a vet.
Heatstroke is an emergency.
What should you do if you think your dog has heatstroke?
There is a very simple message I want you to remember:
Cool first. Transport second.
This is the approach promoted by the Royal Veterinary College.
That does not mean delaying veterinary help.
It means start cooling your dog immediately rather than putting a dangerously hot dog straight into a hot car and doing nothing until you reach the vet.
1. Stop exercise immediately
Do not ask your dog to finish the walk.
Do not slowly stroll home because you are only five minutes away.
Stop.
Move them away from the heat.
2. Move your dog somewhere cool
Find shade or move indoors to a cool, well-ventilated area.
Use a fan or air conditioning where available.
Air movement helps cooling, particularly when the dog’s coat and body are wet.
3. Start cooling with water
This is the section where advice has changed since the article’s original publication in 2016.
You may have previously been told never to use cold water on a dog with heatstroke.
Current PDSA first-aid advice says that cold tap water is fine and recommends gently pouring it over the body, avoiding the nose and mouth.
The Royal Veterinary College advises using water that is cooler than the dog and combining wetting with air movement for evaporative cooling. (Royal Veterinary College)
The important point is:
Do not delay cooling while you try to find the perfect water temperature.
Start cooling.
Go carefully so you do not cause your dog to panic.
Keep water away from the nose and mouth so they do not inhale it.
4. Create airflow
Use a fan.
Use air conditioning.
Open windows and doors where safe.
A breeze over a wet dog can help with evaporative cooling.
5. Offer water but do not force them to drink
Offer your dog a drink.
Let them take small amounts if they want to.
Do not force water into their mouth.
Both the PDSA and RVC advise offering water without forcing an overheating dog to drink.
6. Contact your vet
Phone your vet as soon as possible.
Tell them:
What your dog has been doing
How long they have been in the heat
What signs you have seen
What cooling you have already started
Follow their advice.
Even if your dog appears to recover, the RVC advises having them assessed unless your vet tells you otherwise because more serious effects may not be immediately obvious. (Royal Veterinary College)
Do not wrap a hot dog in a wet towel
A wet towel can be useful for a dog to lie on.
That is different from wrapping a hot dog in one.
The PDSA advises against covering or cuddling an overheating pet with a wet towel, as it can make it harder for them to lose heat. (PDSA)
Think:
Water on the dog.
Air moving around the dog.
Not a wet blanket wrapped around them.
What about putting a dog straight in the car?
You need veterinary advice quickly.
But think about the journey.
Putting an already overheated dog into a baking-hot car without letting it cool first is not helping them.
Start cooling.
Phone the vet.
Use air conditioning or open windows during the journey where safe.
Continue cooling while travelling if another person can safely help.
The PDSA advises travelling in an air-conditioned vehicle or with the windows open and, where possible, having somebody continue cooling the dog during the journey.
Which dogs are more at risk of heatstroke?
Any dog can overheat.
However, some need extra care.
The Royal Veterinary College identifies higher-risk groups including:
Overweight dogs
Flat-faced dogs
Dogs with thick coats
Older dogs
Very young dogs
Dogs with airway, lung or heart problems
The Kennel Club also highlights larger, more energetic dogs as a group that may have an increased risk.
I would also pay particular attention to a dog who simply does not have an off switch.
You know the type.
Ball.
Ball.
Ball.
Ball.
Collapse in a heap.
Some dogs need us to make the sensible decision for them.
Flat-faced dogs and hot weather
Pugs, Bulldogs, French Bulldogs and other flat-faced dogs can have more difficulty cooling themselves effectively.
Breathing is already more challenging for some of these dogs.
Heat adds another problem.
I would be especially cautious with exercise during warm weather and watch for changes in breathing.
Heavy panting or noisy, distressed breathing should never simply be dismissed as:
He always pants like that.
Know what is normal for your dog.
Notice changes.
Can dogs get heatstroke on a walk?
Yes.
Exercise is a major heatstroke risk.
The Royal Kennel Club currently describes exercise as the most common cause of heatstroke and advises walking in the cooler parts of the day, carrying water and taking particular care with dogs who are unwell or dehydrated.
This is why I do not work to a rigid:
A dog has booked an hour, so the dog must walk for an hour.
Safety comes first.
During hot weather I may:
Walk earlier
Shorten a walk
Choose a shaded route
Slow the pace
Increase water breaks
Swap physical exercise for calm enrichment
Cancel a walk when conditions are unsafe
My “Walking Your Dog in Summer” guide explains how I adapt walks for warm weather.
All my dog walking services are also subject to my Extreme Weather Policy
A missed walk is better than heatstroke
I say this a lot during hot weather.
A missed walk will not ruin your dog.
A dangerously hot walk could make them seriously ill.
Dogs do need exercise and enrichment.
But those things do not always have to involve marching around the streets for an hour.
During very warm weather you can use:
Sniffing games
Scatter feeding
Cardboard box searches
A Kong or suitable food toy
Short training games
Calm scent work
Simple garden searches when the garden is cool and shaded
My Summer Dog Safety Guide has more ideas for reducing physical activity while still giving your dog something useful to do.
What I carry and recommend in hot weather
For normal summer walks, preparation helps.
I carry water and pay close attention to the dog in front of me.
I also think about the route, shade, pavement temperature and how quickly I can get a dog home if conditions change.
I have put the practical items I use or consider useful in my Hot Weather Dog Kit.
That page is about preparation.
It is not an emergency heatstroke kit.
No product replaces cooling your dog and getting veterinary help when heatstroke is suspected.
The original Finchley Vet contribution
This article first appeared in 2016 with a contribution from Dr Oli Robinson of The Finchley Vet.
The key message then was that severe heatstroke could rapidly become fatal and that immediate cooling and veterinary treatment were vital.
That message remains important.
What has changed is some of the detail around first-aid cooling.
Research and veterinary guidance move on.
That is why I have replaced the older water-temperature advice on this page with current guidance from the PDSA and Royal Veterinary College.
The Finchley Vet’s current website lists Dr Oli Robinson as Vet and Founder of the independent Finchley practice. (The Finchley Vet)
My simple heatstroke checklist
Think your dog is overheating?
Stop exercise.
Move them somewhere cool.
Start cooling with water.
Create airflow.
Offer water without forcing them to drink.
Phone your vet.
Follow the vet’s advice.
Remember:
Cool first. Transport second.
Final thoughts
Hot weather is one of those times when doing less can be the better choice.
You do not need to prove how fit your dog is.
You do not need to complete your normal route.
You do not need to get your money’s worth from an hour-long walk.
Watch the dog in front of you.
If something does not look right, stop.
When heatstroke is suspected, start cooling immediately and contact your vet.
For wider warm-weather advice, start with my Summer Dog Safety Guide
And if you use a dog walker, ask them a simple question:
What do you do when it becomes too hot to walk safely?
My answer is in my Extreme Weather Policy.
Disclaimer
I am a professional dog walker with an Ofqual Level 3 canine first aid qualification, but I am not a veterinary surgeon. This guide is for general information and first-aid awareness only. It does not diagnose or treat heatstroke. If you think your dog may have heatstroke, start cooling them immediately and contact a vet.
Heatstroke is only one veterinary emergency dog owners should recognise. I have also put together a guide to warning signs that mean your dog may need a vet
Other related articles you may be interested in
