My dog is panting heavily and weak in the heat: is it heatstroke and what do I do?

The first properly hot day in June: 31 degrees in the shade. You took the dog out at two in the afternoon like every other day, on tarmac. About halfway round he stopped and went looking for shade. He was panting with a wide red tongue hanging off to one side, and his saliva was coming in thick strings. You walked another two hundred metres and he sat down. Now he is lying on his side, breathing fast and shallow, not getting up when you call him, and his gums are dark red. That is heatstroke. In dogs it kills, sometimes even after the dog seems to have come round. Below is what to do in the next ten minutes, what to tell the vet and how to make sure you never end up here again.

What to do in the next 10 minutes

Dogs do not sweat. They get rid of heat by panting and through the little skin that has no fur on it. When the air is hot and humid, panting stops cooling anything, and body temperature climbs within minutes. Every minute above 41 degrees kills cells in the brain, the kidneys, the gut and the system that stops bleeding. So the order is simple: cool him first, travel second, and do both quickly.

1. Stop everything and get him into the shade, or into an air-conditioned building. Take off his harness, muzzle, coat, whatever he has on. If you can, lay him on something cool: tiles, shaded concrete, wet grass.
2. Soak him in cold tap water, lots of it, all over. Hose, shower, bucket, bottles of water from the nearest shop, the lake or the river if one is close. The water goes on the body, not the head: belly, groin, armpits, neck, paws, back. If he is a young, conscious dog who can stand, the quickest way to cool him is to put him in cold water up to the neck (a bath, a paddling pool, a stream), head out, with you right beside him. The water has to be running or changed constantly, because water that has warmed up in the coat does nothing.
3. Get the air moving. A fan, the car air conditioning with the windows down, any draught at all. Water evaporating off a wet coat cools several times faster than wetting on its own.
4. Do not wrap him in wet towels and leave them there. A wet towel on a dog warms up within two minutes and turns into a blanket. If towels are all you have, soak them, lay them on, take them off after a minute, soak them again. Ice straight on the skin and ice baths are not for an old dog, a small dog or one who has lost consciousness: they close down the blood vessels under the skin and can set off shivering, and shivering makes heat. Plenty of cold tap water does more than any ice.
5. A little water to drink, and only if he can swallow by himself. Never pour water into the mouth of a dog who cannot stand or is dazed; it goes into the lungs.
6. Ring your vet or an out-of-hours clinic while you are wetting him, phone on speaker. Tell them you are bringing in a dog with heatstroke so they have the drip and oxygen ready.
7. After the first 5 to 10 minutes of cooling, set off for the practice, or straight away if he is unconscious or fitting. Keep cooling on the way: dog wet, lying on a wet blanket, air conditioning on full, windows open a crack. If you have a thermometer and know how to take a rectal temperature, check it. At around 39.5 degrees you stop active cooling: the temperature keeps falling a few tenths on its own, and you do not want to overshoot. With no thermometer, stop when you can see the panting has eased and the dog starts taking an interest in what is around him.

A dog who has perked up in the park has not been saved yet. The kidneys, the gut and the clotting system fail 12 to 48 hours later, and none of it shows from the outside. The trip to the vet happens regardless.

How to recognise the stages

What to tell the vet and what they do

On the phone and when you arrive

• What he was doing when it started: walking, running, playing, sitting in the car, out in a garden with no shade; and for how long.
• When the signs started and what you noticed first.
• His temperature, if you took it, and at what time.
• How you cooled him: with what, from what time until what time, and when the panting started to ease.
• Vomiting, diarrhoea, blood, urine, if there was any and what it looked like.
• How aware he was: did he respond to his name, could he get up, did he fit, did he lose consciousness and for how long.
• Breed, age, weight, whether he is flat-faced, whether he is overweight, any heart or breathing disease, any medication.

At the practice

1. Temperature and signs of shock: pulse, gum colour, how fast the colour comes back when pressed, blood pressure. That tells the vet whether to carry on cooling or stop.
2. Oxygen and a drip, nearly always. The drip holds up blood pressure, protects the kidneys and replaces what he lost through vomiting and diarrhoea.
3. Bloods: kidneys, liver, blood sugar (it drops in heatstroke), electrolytes, clotting, full blood count. They get repeated at 12 to 24 hours, because the worst changes turn up late.
4. Protecting the gut, which takes the first hit and lets bacteria leak into the blood; plus stopping the vomiting.
5. Monitoring for 24 to 72 hours, often as an inpatient: temperature, urine output, breathing, heart rhythm, neurological state. A dog who looks fine in the evening can be in kidney failure by morning. That is why the vet will not send him home just because he "seems fine".
6. Complications, if they appear: clotting problems, abnormal heart rhythms, swelling of the brain, infection in the blood. Each has its own treatment, given at the clinic. None of them is something you treat at home.
7. At discharge you find out what to keep an eye on (appetite, urine, stools, how he walks, how he behaves), when to come back for a recheck with bloods a few days later, and the rule every vet will tell you: a dog who has had heatstroke once gets it more easily the second time.

A wagging tail in the waiting room is no reason to go home relaxed. If your vet suggests bloods and an overnight stay, say yes.

How to prevent it

Most heatstroke in dogs does not happen in hot cars, although dogs do die in them. It happens on walks and during play in the heat, with a dog who does not know when to stop and an owner who did not know it was their job to stop him.

Who is most at risk

Summer rules

• Walk early in the morning and late in the evening. Above 25 degrees, a healthy dog walks slowly, in the shade, with water in your bag. Above 28 to 30, flat-faced and overweight dogs go out for toilet breaks only. Humidity counts as much as temperature: at 26 degrees in humid air, panting cools badly.
• The tarmac test. Hold the back of your hand on the tarmac for five seconds. If you cannot stand it, neither can his pads, and the heat from the ground rises into his body.
• No running, fetch or cycling in the heat. Play is the most common cause, because a dog who is wound up about a ball will not stop on his own. You are the brake.
• Water and shade everywhere: in the garden, in the car, in your rucksack. Wet him before any outing in the heat and let him get into water whenever he finds some.
• The car, never. At 22 degrees outside, a parked car goes past 40 inside within half an hour, and leaving a window cracked changes nothing. Not five minutes, not in the shade.
• A healthy weight. It is the simplest protection against heatstroke, and his joints and heart benefit too.
• The early signs: a tongue wide as a shovel, red, with the tip curling up, panting that does not ease when you stop, looking for shade, slowing down. When you see them, you head home there and then.
• Cooling vests and mats only help while they are wet or cold. They are no substitute for walking at the right time of day.

In summer our training sessions run trails early in the morning and keep them short. A dog working hard with his nose builds up a lot of heat. We have stopped trails halfway because the handler on the end of the line felt perfectly fine, while the dog's tongue was telling us he had had enough. If you do not yet have a regular vet and an out-of-hours clinic saved in your phone, our related services page explains how to choose one. Save the numbers before the first hot day.