Cat Breathing Fast: Normal Breathing Rates and When It Is an Emergency

A cat breathing fast at rest, and above all a cat breathing with its mouth open, may be struggling for air, and that is one of the clearest emergencies in cat care. A healthy adult cat asleep usually breathes about 20 times a minute and you can barely see it. A sleeping rate consistently above 30, breathing that takes visible effort, or any open-mouth breathing at rest means a call to the vet, and the open mouth means going now.

Cats hide illness well, and breathing problems are no exception: by the time a cat is visibly struggling, the underlying problem has often been building quietly. This guide covers what normal looks like, how to count it at home, the signs that cannot wait, and the usual causes.

What normal breathing looks like

Normal cat breathing is slow, quiet, and almost invisible, with the chest rising gently and the mouth closed. PDSA puts it simply: you should not be able to hear or see your cat breathing unless you look and listen very closely¹.

The best data on normal rates comes from owners counting at home. In a study published in the Journal of Feline Medicine and Surgery, owners of 87 healthy cats counted breaths while their cats slept, on 8 to 10 separate occasions each. The median sleeping rate was about 19 breaths a minute, and only 4 of the 85 healthy cats with full data averaged 30 or more². Rates counted while awake but resting were consistently a few breaths higher, with a median around 25 in the healthy cats². That study is why vets use 30 breaths a minute asleep as the line above which a cat deserves a closer look.

How to count your cat’s breathing rate

Count while your cat is in a deep, relaxed sleep: watch the chest or flank rise for 30 seconds, count each rise as one breath, and double it. Skip the counts taken while they are dreaming, purring, or have just settled after play, all of which push the number up.

Do it a few times over a week or two while your cat is well, at different times of day, and write down the results. The researchers found sleeping rates varied very little from day to day in the same cat², so once you know your cat’s usual number, a change stands out. Many vets ask owners of cats with known heart disease to count every day for exactly this reason.

Emergency signs: go to the vet now

Ring your vet or the nearest emergency clinic straight away if your cat is breathing through its mouth or panting at rest, or shows any sign of effort to breathe. Cats almost always breathe through their nose, so mouth breathing is a warning sign in itself¹. The Cornell Feline Health Center advises that any time there is a question about whether a cat is breathing comfortably, it should get to a vet right away, because a cat in respiratory distress is at high risk of dying without prompt treatment³.

The signs to know are:

• Open-mouth breathing or panting that does not settle within a minute or two of rest.
• An unusual posture: crouched, with elbows held out from the chest and the head and neck stretched forward, which the Royal Veterinary College lists among the signs of respiratory distress⁴.
• A belly that heaves visibly with each breath, or breathing that looks like hard work.
• Pale, grey, or blue gums or tongue.
• Noisy breathing, wheezing, or repeated coughing or gagging that looks like an attempt to vomit, which Cornell notes can be a sign of breathing trouble in cats³.
• Collapse, restlessness, or a cat that refuses to lie down.

If you are not sure, treat it as an emergency. This is one of the situations covered in our guide to when a cat needs the vet, and it never belongs in the wait-until-morning list.

What causes fast or laboured breathing

The main causes are heart disease, fluid around the lungs, asthma, respiratory infections, injury, heatstroke, and less often anaemia or cancer. Fear and stress can also raise breathing briefly, but that settles once the cat is calm¹.

• Heart disease. Hypertrophic cardiomyopathy, a thickening of the heart muscle, is a common heart disease in cats and often causes no signs until fluid builds up in or around the lungs. In the home-counting study, sleeping rates above 30 turned up mainly in cats whose hearts were already badly enlarged, which is why a rising count is worth acting on².
• Fluid around the lungs (pleural effusion), which stops the lungs from expanding and can come from heart failure, infection, or cancer³.
• Asthma. Feline asthma narrows the airways, causing coughing, wheezing, and sometimes sudden attacks of open-mouth breathing.
• Respiratory infections. Cat flu usually affects the nose and eyes more than the breathing rate, but severe cases and pneumonia can make breathing hard. Our guide to cat flu covers the milder end.
• Injury, such as a road accident or a fall, which can bruise the lungs or let air into the chest even when the outside of the cat looks fine.
• Heatstroke, in a cat shut in a hot room, car, or conservatory.
• Something stuck in the nose or windpipe³.

Flat-faced breeds such as Persians can breathe more noisily as a matter of course because of the shape of their nose and face¹, which makes knowing their normal even more important.

Getting a struggling cat to the vet safely

Keep your cat as calm and still as you can, because stress makes breathing worse, and go straight to the vet rather than trying to treat anything at home. The RVC notes that stress can make an animal breathe harder and that vets sometimes delay tests until the cat is stable for exactly this reason⁴.

• Ring ahead so the clinic can have oxygen ready.
• Lift your cat gently into the carrier, ideally one that opens from the top, rather than chasing them. Our guide to getting a cat into the carrier has techniques that cut the struggle.
• Keep the carrier level, the car cool and quiet, and the journey as short as possible.
• Do not try to give food, water, or any medicine.

If your cat stops breathing, PDSA advises starting CPR and contacting your vet immediately¹.

What the vet will do

The first job is stabilising your cat, usually with oxygen and minimal handling; finding the cause comes once they are breathing more easily. After that, the vet will listen to the heart and chest and may use X-rays, an ultrasound scan of the chest, or blood tests.

Treatment depends on what is found. Fluid around the lungs can be drained with a needle, which often brings rapid relief; asthma is treated with medication to open the airways; heart failure is managed with medication to clear fluid and support the heart³. Many cats come home and do well, sometimes with a daily count of their sleeping breath rate as part of the plan. For the wider picture of how cats show illness, see our guide to the signs your cat is sick.

A note from Hannah

The first time I counted a cat’s breathing was the night I sat up with a foster cat who had come in thin and quiet, watching her flank go up and down far too fast for a sleeping cat. I counted 44 in a minute, rang the out-of-hours vet, and felt a bit silly on the drive. I did not feel silly when they put her straight into an oxygen tent. She had fluid around her lungs, and she pulled through. Now I count every cat in the house while they are well, once in a while, and write the numbers down. It takes a minute, and it means that on a bad night I have a fact rather than a feeling.

This guide is general information, not advice about your own cat. If your cat is breathing fast, breathing with effort, or breathing through their mouth, contact your own vet or an emergency clinic straight away.