Pugs have significant trouble breathing and cooling themselves due to their pushed-in facial structure.
Pugs
Like Pugs, Bulldogs struggle to pant sufficiently making them very susceptible to heatstroke.
Bulldogs
Brachycephalic Boxers don't cool efficiently through panting just like other short-nosed breeds.
Boxers
Tiny Chihuahuas have a much greater surface area relative to their body mass causing faster heat gain.
Chihuahuas
Obese dogs have a harder time regulating their body temperature.
Overweight Dogs
Puppies and seniors can't regulate their temperature well.
Very Young or Very Old Dogs
Heavy, dense coats trap heat unless brushed frequently.
Thick-Coated Dogs