Heat Stress in Cats: Why Panting Is Never Normal

Quick answer

A cat in the heat gets quieter, flatter and stiller. It does not pant its way through the afternoon like a dog.

A cat with heat stress does not look like a dog with heat stress. Dogs pant, and owners are used to it. Cats hardly pant at all, so a cat that is panting is already in trouble, and by the time it is obvious the situation is an emergency.

The signs to watch for are quieter than panting: seeking out a cool hard floor and staying there, restlessness followed by stillness, unusual grooming to wet the coat, and a cat that goes flat rather than distressed.

• Open-mouth breathing or panting in a cat is abnormal at any time. Treat it as an emergency.
• Cats overheat in still, unventilated indoor spaces far more often than in the open air.
• Flat-faced cats, overweight cats, kittens, elderly cats and cats with heart or breathing conditions are at much higher risk.
• Cool with room-temperature or cool water on the coat and with airflow. Never with ice or iced water.
• Get veterinary help while you are cooling, not after. Internal damage continues after the cat looks better.

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Panting in a cat is not the same as panting in a dog.

Dogs pant routinely to lose heat. Cats do not. A cat pants only when it is under considerable strain, and open-mouth breathing in a cat means overheating, breathing difficulty, heart disease, severe pain or extreme stress.

There is no version of it that means the cat is simply warm and coping. Any cat breathing with its mouth open, or with rapid effortful breathing at rest, needs veterinary care immediately.

Do not put a panting cat into a carrier and wait to see if it settles. Cool it, and phone a clinic on the way.
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Why cats overheat differently

A cat's cooling system is built for a desert ancestor that avoided the heat rather than working through it.

Grooming and evaporation. The main mechanism. A hot cat licks its coat, and the saliva evaporates and carries heat away. It works well in dry air and poorly in humid air.

Paw pads. Cats sweat a little through the pads, which is why you sometimes see damp paw prints on a hard floor from a stressed or hot cat. It is a very small contribution.

Behaviour. The main defence. Cats move to shade, seek cool surfaces, spread out to increase the surface area they present, and become inactive. A healthy cat given the option will manage its own temperature well.

Panting. The emergency mechanism, and the one that matters here. Cats do not pant as part of ordinary cooling, so a panting cat has exhausted the other options.

The consequence of that design is important. A cat is very good at avoiding heat when it can choose, and very poor at coping with it when it cannot. Heat stress in cats is therefore usually a problem of being trapped: shut in a room, a greenhouse, a car, a shed, a conservatory or a carrier, with no shade, no airflow and no way out.

Humidity multiplies the risk, because both of a cat's main mechanisms depend on evaporation. A humid day at a moderate temperature can be more dangerous than a hot dry one.

Which cats are at higher risk

Flat-faced cats. Persians, Exotics, British Shorthairs with very flat faces and similar breeds have compressed nasal passages and shortened airways. The airflow needed for evaporative cooling and for panting is restricted, so they overheat sooner and cope worse. They also tolerate the stress of a hot carrier poorly.

Overweight cats. Fat insulates, and excess weight increases the work of breathing.

Long-haired and dark-coated cats. More insulation, and more heat absorbed in the sun.

Kittens and elderly cats. Less able to regulate their temperature and slower to move themselves somewhere better.

Cats with heart or airway disease. Any existing limitation on breathing or circulation becomes critical in the heat.

Cats with a history of overheating. A cat that has overheated once is more vulnerable to it again.

Cats being transported. A carrier in a car, in the sun, on a hot day, is one of the most common ways a pet cat overheats.

The early signs, in order

Appetite and drinking are the two things to watch through a hot spell. A cat that goes off its food in the heat is a cat to keep an eye on, not one to leave to it.

Cats deteriorate quietly, so the sequence below matters more than any single sign.

Seeking cool surfaces and staying there. Tiles, baths, sinks, the space behind the toilet, the shaded side of the house. On its own this is normal and sensible.

Stretching out flat rather than curling up. Increasing the surface area is deliberate.

Grooming more than usual. A cat wetting its coat is actively cooling. Excessive grooming with any other sign here is different from grooming as a routine.

Becoming inactive, then restless, then still again. Restlessness and pacing while looking for somewhere cooler is a genuine warning stage. When it stops and the cat goes still, that is not necessarily relief.

Eating less, drinking more. Worth noticing, and worth measuring.

Breathing faster at rest. Watch the chest of a resting cat. This is the point at which to act rather than observe.

Drooling, or the mouth beginning to open. Escalating.

Panting. Emergency, without qualification.

Bright red gums, or very pale gums, tacky to the touch. Emergency.

Vomiting or diarrhoea. Overheating damages the gut lining, and this is a sign of serious illness rather than an upset stomach.

Wobbliness, disorientation, tremors, collapse, seizures. Emergency.

Do not try to take a temperature at home. Ear and forehead thermometers are unreliable in cats, restraining a distressed cat makes everything worse, and no number would change what you should do. Act on the signs.

Cooling a cat safely

Start cooling immediately and arrange veterinary help at the same time. Do not choose between them.

Move the cat to the coolest place available. Indoors, shaded, tiled floor, out of any direct sun.

Get air moving. A fan directed at the cat, or a draught between two open windows. Airflow is what makes evaporation work, and evaporation is what actually removes heat.

Wet the coat with cool or room-temperature water. Pour or sponge it over the body, the neck, the armpits, the groin and the paws. Work it through to the skin, because water sitting on top of the fur does very little. Keep it off the face.

Keep it wet and keep the air moving. Reapply. A single soaking followed by nothing does not help much.

Offer water to drink but never force it. A cat that is disoriented or breathing hard can inhale liquid. Put a bowl within reach and leave it.

Do not use ice, iced water or ice packs against the skin. Extreme cold makes the surface blood vessels clamp shut, which traps heat inside the body, and it can cause shivering that generates more heat. Cool, not cold.

Do not cover the cat with a wet towel and leave it. A towel laid over a cat traps warm air and stops evaporation. It is worse than nothing. If you use wet towels, keep replacing them with freshly cooled ones and keep the air moving.

Do not stop cooling too late. Cooling can be overdone, so the aim is to cool on the way to the clinic and let the clinic take over. Tell them what you have already done.

Travel with the windows open or the air conditioning on, and keep the carrier out of direct sun.

Preventing it

Most feline heat emergencies come from a cat being somewhere it could not leave.

Count the cats before you close any door. Sheds, greenhouses, conservatories, garages, cars, wardrobes, tumble dryers. A cat that goes in to sleep somewhere warm and is shut in has no way out.

Never leave a cat in a parked car. Not with the windows cracked, not in the shade, not briefly. The interior temperature rises far faster than people expect.

Keep a conservatory or a sun room shut off on hot days, or ventilated and shaded.

Provide shade and cool surfaces indoors. Close curtains on the sunny side, leave a tiled floor accessible, keep the bathroom door open.

Ventilation over cooling. Cats do better with moving air than with a cold room. A fan they can move away from is ideal.

Several water stations, away from food. Wide, shallow bowls, refreshed daily. Some cats drink much more from a running fountain. Water outdoors as well if the cat goes out.

Shift activity to the cool hours. Play in the early morning and the evening, not the middle of the day.

Keep long coats free of mats. Matted fur prevents air reaching the skin and traps heat. Do not shave a cat without veterinary advice, because the coat also provides insulation against heat and protects against sunburn.

Watch white ears and noses. Pale, thinly furred skin burns, and repeated sun damage on cats' ear tips can progress to skin cancer. Shade is the answer.

Plan car journeys carefully. Travel early or late, never leave the cat in the car, and keep the carrier out of the sun and in moving air.

What never to do

Do not use ice, iced water or ice packs on the skin.

Do not cover a hot cat with a wet towel and leave it in place.

Do not force water into a cat's mouth.

Do not give any human medication, and never paracetamol, which is lethal to cats.

Do not leave a cat in a car, a conservatory, a greenhouse or a shed, at any temperature that feels warm to you.

Do not assume a cat panting after a car journey or a stressful event will settle. Cats do not pant to cool down.

Do not shave a cat to keep it cool without asking your vet. The coat insulates in both directions and protects the skin from the sun.

Do not wait to see how the cat is later. Heat injury progresses after the cat looks better.

When to get help

Go to a veterinary clinic immediately, out of hours if necessary, for panting or open-mouth breathing, rapid or effortful breathing at rest, drooling in a hot cat, bright red or very pale gums, wobbliness, disorientation, collapse, tremors, seizures, or vomiting and diarrhoea in the heat.

Go immediately if your cat has been shut in a car, greenhouse, shed or conservatory, even if it appears to have recovered.

Call the same day if a cat has been unusually flat during hot weather, has gone off its food, or is passing less urine than usual.

Recovery is a cat back to its usual breathing, appetite and activity. Anything short of that in the days afterwards is a reason to go back.

Tell the clinic how long the cat was exposed, what you found it doing, what cooling you have already done, and what its breathing and gums looked like. Keep cooling with airflow on the way in, and keep the carrier out of the sun.

Keep the carrier accessible through the summer rather than in the loft. In a heat emergency you are cooling and travelling at the same time, and hunting for a carrier is time the cat does not have.