I don't agree with most of the sentiments in this thread. I'm both spiritual and aware. :)
Traditional spiritual practices such as yoga, meditation, and breathing exercises have very powerful transformative effects and can have many physical, psychological, and spiritual benefits. Not to mention they have been used to achieve enlightenment by cultures all over the world for thousands of years.
Anyway, I know it works from personal experience. It's not a matter of belief but something you have to experience, in my opinion.