Bulldog,  also known as the British Bulldog or English Bulldog, is a medium-sized dog breed. According to the American Kennel Club (AKC), a Bulldog's disposition should be 'equable and kind, resolute, and courageous (not vicious or aggressive), and demeanor should be pacifist and dignified. These attributes should be countenanced by the expression and behavior'. Wide stance Breeders have worked to reduce/remove aggression from these dogs. Most have a friendly, patient, but stubborn nature. The condition manifests in a variety of ways, often in the form of intolerance to heat and physical exertion. The English bulldog is among the breeds that are most severely affected by brachycephalic airway obstructive syndrome. Bulldogs have very small nasal cavities and this makes them have great difficulty keeping their bodies cool. The English bulldog is among the breeds that are most severely affected by brachycephalic airway obstructive syndrome.