Counting breaths in sleep: what ACVIM and home-monitoring studies treat as a reason to call

VCA’s Home Breathing Rate Evaluation states that a typical rate while calmly resting or sleeping is about 15–30 breaths per minute in dogs and cats; heat, stress, or activity can push it much higher. Rates consistently above 30 are increased and abnormal, and some individuals have a lower personal threshold set by their veterinarian.[4]

Ljungvall et al. (2014, Journal of Feline Medicine and Surgery) had owners measure rates at home. Echocardiographically normal cats, apparently healthy cats, and most cats with subclinical heart disease (mostly HCM) and only mild-to-moderate left-atrial enlargement usually had mean sleeping rates below 30 (median about 21). Cats with severe left-atrial enlargement more often exceeded 30. The authors concluded that a mean rate >30, or multiple readings >30, likely warrants further evaluation.[5]

Cornell’s cardiomyopathy page describes cats in congestive failure as often breathing faster than 35 breaths per minute at rest, and lists sudden hind-limb lameness or paralysis (saddle thrombus) as an emergency.[2] That does not cancel the “30” used by VCA and ACVIM: 30 is a common home-monitoring call-the-clinic line; 35 plus labored or open-mouth breathing describes decompensation. Follow the threshold your veterinarian gave you.

VCA prefers counting during sleep, or while the animal is quietly resting; do not count a purring cat, because purring distorts the pattern. Sleeping rates are typically a little lower than resting rates.[4] Ljungvall’s data were also collected at home, on multiple occasions — not once on an exam table.[5]

In practice: one full chest or belly rise is one breath. Count a full 60 seconds (or 30 seconds × 2, which VCA also describes).[4] A single high reading can be REM sleep, room temperature, or a counting error. WSAVA 2017 home-monitoring teaching notes that resting/sleeping rates are generally <30 in healthy animals and those with preclinical disease; repeated values >30 should prompt a call — a few isolated highs are less alarming than a sustained rise, which you should not ignore.[6]

Cornell is explicit: HCM is diagnosed by echocardiography; hypertension and hyperthyroidism can also thicken the heart and must be ruled out.[1] Fast breathing also occurs with asthma, pain, anemia, fever, and other problems. The home number exists so you can say “sleeping breaths went from 22 to often 34 this week,” and the veterinarian can decide whether to bring the visit forward or image the heart.