The breathing crisis hiding in plain sight: new genetics research gives hope to bulldog, pug, and French bulldog owners
Doges Editorial · 2026-05-15 · 5 min read
A landmark study from the Royal Kennel Club has cracked the genetic mystery behind why flat-faced breeds struggle to breathe — and found that smarter breeding programs could reduce the disorder within generations.
If you've ever shared a bed with a French Bulldog, you know the sound. The snuffling, the wheezing, the small rumble in the dark that sounds almost like contentment. Many owners have come to think of it as cute. Vets have a different name for it: brachycephalic obstructive airway syndrome, or BOAS. And a study published on May 13, 2026, in the open-access journal PLOS One may have just opened the first real genetic pathway out of it.
The most popular dog in America has a breathing problem
In 2022, the French Bulldog overtook the Labrador Retriever as the most popular dog breed in the United States — ending a 31-year Labrador reign. French Bulldogs, Pugs, and English Bulldogs are now among the most owned dogs in the world. They are also among the most medically burdened.
BOAS affects flat-faced dogs — a group formally called brachycephalic breeds — because their compressed skulls leave less room for their airways. The result, in varying degrees of severity, is noisy breathing, an inability to exercise comfortably, difficulty regulating body temperature in heat, and in serious cases, the kind of respiratory distress that requires surgery. Despite how common the condition is, the underlying genetics had never been well characterized.
Until now.
What the researchers actually did
Researchers at the Royal Kennel Club, led by Dr. Joanna Jadwiga Ilska, analyzed more than 4,000 Bulldogs, French Bulldogs, and Pugs from RKC breeding records. Each dog was evaluated using a standardized exercise test called the Respiratory Function Grading Scheme — a tool developed with the University of Cambridge that assesses how well a dog breathes before and after a structured walk.
The researchers then ran the results through a quantitative genetic analysis to estimate how much of the variation in respiratory health could be attributed to genetics versus environment. The sample size was five to ten times larger than in any previous study on the subject.
What they found was striking: 21 to 49 percent of the variability in how well these dogs breathe is heritable. Between 31 and 39 percent of the variation in nostril size — a key predictor of airway restriction — is also heritable. And the two traits, along with body weight, tend to cluster together. A dog with narrow nostrils is more likely to also have poor respiratory function and to be overweight.
Our findings provide clear evidence that respiratory health in these breeds is influenced by genetic differences between dogs, and importantly, that improvement is achievable through selective breeding. By using objective tools like the Respiratory Function Grading Scheme, breeders can make more informed decisions that prioritize health, helping to reduce the prevalence of BOAS over time.
— Dr. Joanna Ilska, geneticist and lead author, Royal Kennel Club
The numbers behind the problem
The study found BOAS prevalence rates of 15.6 percent in French Bulldogs, 18.9 percent in Bulldogs, and 19.8 percent in Pugs among tested dogs. The researchers note these rates may actually underestimate the real-world picture, since many flat-faced dogs are only screened for BOAS if they show noticeable symptoms. Dogs with milder breathing problems often go undiagnosed.
But what the study also showed — and this is the hopeful part — is that these rates are potentially lower than earlier estimates. That shift may reflect health management improvements that breeders have quietly been making over the past decade, largely without the benefit of genetic evidence to guide them.
What this means for breeders — and for you
For breeders, the implication is practical and significant: the Royal Kennel Club now has a data-backed argument for avoiding pairings between dogs who grade poorly on respiratory health, who have narrow nostrils, or who carry significant excess weight. These traits travel together genetically, which means selecting against one tends to help with the others.
Increasing participation in health screening is also key to achieving progress and ensuring that future generations of these popular breeds can enjoy better quality of life.
— Dr. Joanna Ilska
The catch is the caveat. This research was conducted exclusively on dogs registered with the Royal Kennel Club. Dogs bred outside that system — and many French Bulldogs and Pugs are bred outside formal registries — are not reflected in the data. The path to improvement runs through broader health screening, which means getting more dogs tested, not just the ones already enrolled in formal programs.
If your flat-faced dog is already here
None of this changes the reality for the millions of flat-faced dogs who are already in homes, already breathing the way they breathe. For them, the Royal Kennel Club offers practical management guidance that researchers echoed in the study: keep them lean (excess weight compounds airway restriction), give them frequent breaks during walks, and keep them cool when temperatures rise. A flat-faced dog exercising in summer heat carries a respiratory load that a Labrador in the same conditions simply doesn't.
For owners of these breeds, the walk itself is a calibration. Shorter bursts in shade, not marathon sessions on warm afternoons. Watching for the labored exhale, the extended recovery time after effort, the posture that says this dog needs to stop before you planned to.
A science of making walks better
There is something quietly important about research like this. It doesn't promise a fix for any dog alive today. But it gives breeders a lever they have never had before — a genetic argument for choosing health over the extreme skull shape that show standards have historically rewarded.
It is also important to recognize that this research is based on dogs within the Royal Kennel Club's registered population and may not reflect those bred outside of this system. This highlights the value of Royal Kennel Club registration, as participation in schemes like the RFGS allows registered dogs to contribute to scientific research that supports the long-term health and welfare of the breed.
— Dr. Joanna Ilska
The snoring in the dark can be a sign of something treatable at the population level, even if it isn't treatable in the individual dog today. Generations from now, a French Bulldog owner might take an uninterrupted walk on a July afternoon — and never know that this study, in a quiet corner of PLOS One, published in May 2026, was one of the things that made it possible.