Well, I don't say the Rosary, but this article still bugs me. I am constantly amazed by the number of people who want to put all religion into the realm of psychological self-help. "Well, I don't believe it personally, but if it helps you cope with life - wonderful!"
Frankly, I couldn't care less if Jesus helped me cope with life. Jesus is G-d. I worship Him because He is. Any benefits to me are secondary - including changing my breathing rate.
By the way, if reducing your breathing rate to 6 breaths/minute is so good for you, are you really healthy if you can get down to zero?
Shalom.