Breathing: The Real Danger Hidden in Flat-Faced Dogs

Beyond appearances, a widespread respiratory risk

Flat-faced dogs have become the symbol of canine respiratory problems. However, attention has long been focused on a handful of very popular breeds. A new study is challenging our assumptions: the problem runs deeper and affects breeds that are sometimes unexpected.

Two lesser-known breeds have been found to be among those most severely affected by chronic airway obstruction. This discovery significantly expands the list of high-risk dogs.

It also challenges the common misconception that only dogs with the flattest, most famous faces struggle for every breath. The reality appears to be far more complex.

Two Breeds at the Center of Concern

To assess the situation, nearly 900 dogs, accompanied by their volunteer owners, participated in respiratory evaluations and short exercise tests. The results showed just how drastically the risk could vary from one breed to another.

Dr. Francesca Tomlinson of the University of Cambridge documented these animals’ performance. Her observations are striking: only 10.9% of Pekingese and 17.4% of Japanese Chin completed the tests without showing any signs of respiratory distress. These percentages place them on the same level of severity as Bulldogs, a breed that is nevertheless much more often singled out for its breathing difficulties.

Notably, other flat-faced breeds showed much higher rates of normal breathing. This demonstrates that the risk is concentrated within specific bloodlines rather than being an inevitable fate for all short-snouted dogs.

What is obstructive airway syndrome?

Veterinarians refer to this condition as Brachycephalic Obstructive Airway Syndrome (BOAS). It is a long-term blockage of the airways that forces dogs to work much harder just to breathe.

How does this happen? Inside a shortened skull, soft tissues—such as the soft palate and tongue—continue to grow to their normal size. They then become cramped, obstructing the airways and restricting airflow.

This resistance becomes particularly dangerous when a dog tries to cool down by panting. The extra effort can cause their body temperature to rise more quickly during exercise, excitement, or stress. In the most severe cases, OBAS can shorten walks, disrupt sleep, and sometimes force owners to opt for surgery to widen the narrowed airways.

Listen to Better Assess Distress

To measure the true extent of a dog’s difficulties, researchers chose to focus on respiratory function rather than physical appearance. At each appointment, staff carefully listened to the animal’s breathing sounds, first at rest and then after a three-minute jog.

A scoring system was implemented. A score of zero indicated silent breathing, even after exertion. Conversely, a score of three was assigned to dogs that visibly struggled to breathe as soon as they began to move.

Between these two extremes, mild cases produced a sound detectable only with a stethoscope, while moderate cases were audible to the naked ear. By assessing actual airflow during light exertion, this test helped identify genuine respiratory distress, even in dogs that appeared perfectly healthy on the outside.

Physical traits that increase the risk

Throughout the evaluations, three characteristics recurred consistently among the dogs with the lowest scores: being overweight, narrowed nostrils, and a very short muzzle. Nostrils that are too narrow can actually fold inward during inhalation, leaving even less space for air to enter.

The researchers used a precise measurement—the craniofacial ratio (muzzle length divided by skull length)—to quantify the degree of facial flattening. But even with these indicators, many results defied expectations. Appearance alone is not enough to assess risk.

The team was also surprised to find that some of the breeds with the flattest-looking faces did not consistently score the worst. In the Cavalier King Charles Spaniel, for example, 40% of the dogs completed the test without any signs of OBSA, despite their very short muzzles. A statistical model combining weight, nostril shape, and craniofacial ratio could explain only 20% of the variation in results. This discrepancy suggests that internal anatomy and genetics play a significant role, making a functional respiratory test essential.

Breed-Specific Vulnerabilities

The study revealed other clues—this time related to physical characteristics beyond the face—that appear to be specific to certain breeds. These findings suggest weaknesses unique to each breed.

In Staffordshire Bull Terriers and Shih Tzus, a shorter tail was associated with a higher risk. Conversely, a longer tail reduced their chances of developing the syndrome by about 30%. Affected Staffordshire Bull Terriers had tails that were, on average, 0.6 inches (about 1.5 cm) shorter.

In the case of the Boston Terrier, a thicker neck was found to be an indicator of respiratory problems. Since these patterns vary from one breed to another, the study advocates for the development of breed-specific checklists rather than the application of a one-size-fits-all rule.

Owners and Breeders: How Can We Reverse This Trend?

For owners, simple choices can make a real difference. Before adopting a brachycephalic puppy, observing its breathing at rest and then during a short walk can reveal early warning signs. During a veterinary visit, the veterinarian can assess the dog’s breathing and recommend weight loss, surgery, or lifestyle adjustments to improve the animal’s comfort.

In hot weather, limiting intense exercise is crucial, as OBHS impairs a dog’s ability to cool down. But beyond these steps, the study’s central message is simple: a dog should never have to struggle to breathe.

In the long term, change will depend on breeding selection criteria. In dog shows, judges often favor extreme facial features that increase the risk, thereby influencing future litters. Another path is possible: dogs that perform well on respiratory tests could become healthier models for breed standards. Selecting animals for open nostrils and good respiratory function, rather than for exaggerated features, could reduce the risk of SAOB without waiting for a miracle genetic solution.

Today’s choices shape tomorrow’s health

The researchers point out that their study has limitations. The recruitment of volunteers likely skewed the sample, as owners who were already concerned about their dog’s breathing were probably more inclined to participate. Furthermore, the comparison data dates back to 2016, which may not perfectly reflect the current situation if recent breeding decisions have improved the respiratory function of certain bloodlines.

The overall message, however, remains clear. Since SAOB is hereditary, long-term progress depends on rigorous breeding choices. Improving the well-being of these breeds will likely rely on a combination of routine respiratory evaluations, smarter show standards, and increased awareness among owners, who must stop viewing chronic snoring or labored breathing as “just a normal sound for the breed.”

The study was published in the scientific journal PLOS One.

According to the source: earth.com

Breathing: The Real Danger Hidden in Flat-Faced Dogs