breathing is one of those things you never think about until it goes wrong. I notice it in the exam room immediately — the way a pet breathes tells me more in the first ten seconds than most owners realize. The rhythm, the effort, whether the belly moves or the chest moves, whether the nostrils flare, whether the pet is using their abdominal muscles to push air out. All of it matters.
A Cavalier King Charles Spaniel named Penny came to me because she'd started coughing at night. Just at night, her owner said — a soft, hacking cough that had been going on for about two weeks. During the day, Penny seemed fine. The owner assumed it was allergies. Chest X-rays showed an enlarged heart. Penny was in early congestive heart failure, and the coughing happened at night because lying down increased the fluid pressure in her lungs.
Respiratory and circulatory symptoms in pets overlap more than most people expect, because the heart and lungs work as a single system. A cough isn't always a lung problem. Pale gums aren't always a blood problem. And panting isn't always about heat.
Coughing in Dogs
Dogs cough for a lot of reasons, and the character of the cough matters enormously.
Kennel cough (infectious tracheobronchitis) produces a dry, honking cough that sounds like the dog is trying to clear something from their throat. It's contagious, self-limiting in most healthy adults, and often picked up at boarding facilities, dog parks, or grooming salons. The dog usually feels fine otherwise — eating, playing, no fever. Most cases resolve within one to two weeks. It's the canine common cold, more or less.
Heart disease cough is different. It's softer, often described as a "wet" cough, worse with activity or excitement, and worst at night or early morning. In small breeds especially, a persistent cough that's been around for weeks and is gradually getting worse points toward mitral valve disease — the most common heart condition in older small dogs. Large breed dogs with dilated cardiomyopathy may cough as heart function declines, but they're also more likely to present with exercise intolerance and collapse.
Collapsing trachea produces a distinct goose-honk sound, particularly with excitement, pulling on the leash, or drinking water. It's a structural problem — the tracheal rings lose rigidity and the airway flattens — and it's overwhelmingly a small-breed condition. Yorkshire Terriers, Pomeranians, Chihuahuas. The cough can sound alarming, but the condition is manageable in most cases.
Pneumonia causes a deep, productive cough — you can sometimes hear the moisture in it — along with fever, lethargy, and often nasal discharge. Aspiration pneumonia (from inhaling food, water, or vomit) is a particular concern in brachycephalic breeds and dogs with laryngeal paralysis.
Why Cats Don't Cough Much
Cats coughing is actually unusual, and that's a clinically important distinction. When I see a coughing dog, I have a long differential list. When I see a coughing cat, the list is short.
Feline asthma is the most common cause of coughing in cats. It looks dramatic — the cat crouches low with neck extended, coughs or wheezes, and sometimes has audible respiratory effort. Severe episodes can progress to respiratory distress. Asthma in cats responds to the same classes of medications used in human asthma — bronchodilators and corticosteroids — and some cats even use inhalers designed with a feline spacer device.
Heartworm disease in cats presents differently than in dogs. Cats may cough, wheeze, vomit, or simply become lethargic. The disease is harder to diagnose in cats and harder to treat — there's no safe adulticide therapy for feline heartworm like there is for dogs. Prevention is far more effective than treatment.
What cats do that owners sometimes mistake for coughing is retching or gagging before vomiting a hairball. The posture and sound are different from a true cough, but the distinction can be subtle. If you're unsure, a short video clip on your phone is worth more than any verbal description you can give your vet.
Panting: Normal and Not
Dogs pant to cool themselves.That's their primary thermoregulation mechanism since they have very few sweat glands. For more about heart health in dogs, see our detailed guide. After exercise, in warm weather, when excited — panting is expected.
Panting that concerns me: at rest, in a cool environment, without recent exertion. A dog who's lying on the living room floor in an air-conditioned house and panting heavily is telling you something.
Possible causes of pathological panting include pain (especially abdominal or thoracic pain), anxiety or stress, Cushing's disease, anemia (the body compensates for reduced oxygen-carrying capacity by increasing respiratory rate), heatstroke, and congestive heart failure.
Brachycephalic breeds — Bulldogs, Pugs, French Bulldogs, Boston Terriers — pant more than other dogs because their compromised airways make breathing harder at baseline. This doesn't mean their panting is always normal. It means you have to calibrate your concern against their individual baseline, which is already elevated. A Bulldog whose breathing is louder or more labored than their usual loud, labored breathing needs attention.
One pattern I want to highlight: panting combined with restlessness and a distended abdomen in a large, deep-chested dog (Great Dane, German Shepherd, Standard Poodle) should trigger immediate concern for gastric dilatation-volvulus — bloat. This is a true surgical emergency.
Gum Color as a Diagnostic Window
I mentioned gum color in the full guide to pet health warning signs, but it deserves expansion here because it directly reflects circulatory status.
Healthy pink. Salmon-colored, moist gums with a capillary refill time (press and release — the white spot should return to pink) of under two seconds.
Pale or white. The blood isn't getting there — either because there isn't enough blood (anemia from blood loss, hemolysis, or bone marrow failure) or because circulation has shifted centrally (shock). A dog who's pale and lethargic with a fast heart rate could be bleeding internally. I've seen splenic tumors rupture with no external signs except progressive weakness and blanching gums.
Blue or purple (cyanosis). Not enough oxygen in the blood. This means severe respiratory compromise — the lungs aren't exchanging gas effectively, or there's a cardiac shunt, or the airway is obstructed. Cyanosis is an emergency. Every time, without exception.
Bright brick red. Toxin exposure (particularly carbon monoxide), heatstroke, or sepsis. The vasodilation gives gums an unusually vivid color. It looks healthy at first glance — redder than normal — but it's not.
Yellow (icterus). Bilirubin accumulation from liver disease or massive red blood cell destruction. The gums, inner ears, and whites of the eyes all take on a yellowish tint.
Some breeds have naturally pigmented gums — Chow Chows, Shar-Peis, some mixed breeds. In these dogs, check the inner lip, the tongue margins, or the conjunctiva (inner eyelid) instead.
Breathing Rate: A Number Worth Knowing
Normal resting respiratory rate for dogs is 15-30 breaths per minute. For cats, 20-30. Count breaths while the pet is resting or sleeping — watch the chest rise and fall for 30 seconds and multiply by two.
A resting respiratory rate consistently above 40 in a dog or a cat is abnormal. In pets with known heart disease, monitoring resting respiratory rate at home is one of the most useful things an owner can do. An upward trend — 28 one week, 34 the next, 42 the week after — often predicts a heart failure episode before it becomes a crisis.
I have clients who track this number weekly in a notebook. It's simple, it's free, and it has prevented emergency visits by catching problems early enough for medication adjustments during regular appointments.
The Sounds That Should Scare You
Stridor — a high-pitched, squeaky sound on inhale — means upper airway obstruction. Something is narrowing the space where air enters. Laryngeal paralysis (common in older large-breed dogs), a foreign body, severe swelling, or a mass can cause it.
Stertor — a low-pitched snoring sound — is common in brachycephalic breeds and usually reflects elongated soft palate or narrowed nares. If it's their baseline, it's expected (though it speaks to breeding concerns I have strong opinions about). If it's new, something has changed.
Wheezing on exhale suggests lower airway narrowing — asthma in cats, bronchitis in dogs.
Any sudden onset of labored, noisy breathing where the pet is visibly struggling — mouth open, head and neck extended, exaggerated chest and abdominal movements — skip the analysis and go to the emergency clinic. You can figure out why after the pet is stabilized.
Frequently Asked Questions
My dog coughs every morning — is that normal?
A single cough upon waking isn't alarming; mild tracheal irritation from sleeping posture can cause that. Multiple coughs every morning, especially if they're getting more frequent or more forceful, should be investigated. Heart disease and tracheal collapse both tend to produce morning cough patterns. A chest X-ray is the starting diagnostic.
Can secondhand smoke affect my pet's breathing?
Yes. Pets in smoking households have higher rates of respiratory disease, including asthma in cats and bronchitis in dogs. Cats are additionally exposed through grooming — smoke particles settle on their fur and they ingest them while cleaning themselves. This increases their risk of oral squamous cell carcinoma. I don't moralize to clients about personal choices, but I answer this question honestly when asked.
My cat breathes fast when purring — should I worry?
Purring involves rhythmic laryngeal muscle contractions that naturally increase the visible breathing effort. Respiratory rate during purring isn't clinically meaningful. Wait until the cat is quietly resting or sleeping to count breaths. If the rate is consistently above 30 during quiet rest (not purring, not recently active), then yes — have it checked.
What's the difference between a cough and reverse sneezing?
Reverse sneezing in dogs produces a sudden, rapid series of loud inhalations through the nose, often with the neck extended and sometimes with a snorting sound. It looks and sounds terrifying. It's almost always benign — triggered by nasal irritation, excitement, or pulling on the leash. It stops on its own within seconds to a minute. A true cough involves an expulsive exhalation through the mouth. If you're unsure which you're seeing, video it on your phone and show your vet.