Heart health & sleeping breaths

Why Chihuahuas’ hearts get extra attention

Degenerative mitral valve disease is the most common heart disease in dogs — about three-quarters of cases — and it’s more common in small dogs.¹ Chihuahuas are one of the most frequently diagnosed breeds;² in a study of nearly 112,000 dogs, they had about six times the odds of a diagnosis compared with mixed breeds.³

For small breeds without a known problem, the specialists’ guideline recommends a yearly listen with a stethoscope.¹ So the first step is simply asking at each checkup: do Henri or Mizzy have a murmur?

Who this counter is for

Counting sleeping breaths at home is a tool for dogs already diagnosed with a murmur or heart disease, usually once it’s moderate or advanced — cardiologists don’t recommend it for every healthy senior.^4,5 In dogs with heart failure, a rise in resting breathing rate above their normal baseline is the best early warning of trouble.¹ If your vet hasn’t asked you to count, you don’t need to — but it’s a good question for the next visit.

Open the breath counter

How to count

Wait until they’ve been soundly asleep for a while — not twitching, paddling or dreaming.^6,5
Pick a comfortable room (not hot or cold), and not right after activity.⁵ Never count panting.⁷
One breath is the chest rising and falling once.^4,7
Count for 30 seconds and double it, or count a full 60 seconds.^4,5 The counter does the math.
Count at about the same time each day. The first week of counts sets their personal baseline.⁶

What the numbers mean

In a study of 114 healthy dogs, the average sleeping rate was 13 breaths per minute, and no dog averaged more than 23.⁸ Dogs with heart disease but no symptoms generally stay under 25.⁹

When to call the vet

Rates consistently above about 30 per minute are considered increased. Count again a few times over the next couple of hours; if it stays high, call your vet.^4,10
A jump of 25% or more above their own baseline, confirmed over two or three counts, is also worth a call.⁶
A high rate together with other signs — labored breathing, restlessness, weakness — may be an emergency.⁴

Your vet may pick a different number for your dog.⁴ You can set each dog’s alert line on their profile; the default is 30.

Heat, stress and activity all raise breathing rates, and a restless sleep can be mistaken for deep sleep — so one high count isn’t cause for alarm on its own.^4,6

Sources

ACVIM consensus guidelines for myxomatous mitral valve disease in dogs (JVIM, 2019) — Keene BW, et al., American College of Veterinary Internal Medicine
Myxomatous Mitral Valve Degeneration in Dogs — ACVIM pet-owner site (vetspecialists.com)
Degenerative mitral valve disease in 111,967 UK primary-care dogs (JVIM, 2015) — Mattin MJ, et al.
Monitoring Your Pet’s Respiratory Rate — Cardiac Education Group (veterinary cardiologists)
Sleeping Respiratory Rates in Dogs and Cats — Mark Rishniw, BVSc, PhD, DACVIM — Veterinary Partner (VIN)
Home Respiratory Rate Monitoring in Dogs & Cats — Brian A. Scansen, DVM, MS, DACVIM (Cardiology), Colorado State University — Clinician’s Brief
Monitoring Heart Disease Treatment at Home — Cummings School of Veterinary Medicine at Tufts — HeartSmart
Sleeping respiratory rates in apparently healthy adult dogs (Res Vet Sci, 2012) — Rishniw M, et al.
Sleeping and resting respiratory rates in dogs with subclinical heart disease (JAVMA, 2013) — Ohad DG, et al.
Home Breathing Rate Evaluation — VCA Animal Hospitals

Sources checked September 2026. This guide is general education, not veterinary advice for a specific dog.