For me as a one who lives in Eastern country and practiced breathing, I can really say that it helps your body and mind. It is far old tradition to practice some kind of breathing(or zen you say, or yoga for more physical). After a few months of daily practice, I myself experienced amazing response of my body. But never attend classes that has some kind of religious color or ask you to buy some products. They might not be a hoax but some were reported as hoax and made some news in here.