Puffing or rapid breathing in cases of anhydrosis is a result of a reduced sweat cooling to dissipate body heat and therefore the horse rapidly becomes distressed with heat or excercise and ends up panting like a dog. Sometimes the only place they will be able to sweat efficiently is under the saddle blanket. Often, you will notice there is not nearly enough sweat to indicate normal sweating.While the Anhydrosis mix does support the heart, lungs and immunity in a general way, you should have your Vet check your horse and make sure that what you think are "The Puffs" is not primarily a heart, lung or infection problem.