This is an article worth reading. And not only reading. I've been toying with yoga and meditation for some time now, I also learned autogenic training (a powerful relaxation technique, I used it when I had palpitations - long and old story, still helps) and I like to read everything on this subject.
Here is the link:
http://edition.cnn.com/2009/HEALTH/06/01/mindfulness.training.stress/index.html?eref=rss_latest