Let's start this with a bit of introduction to the way I try to present health related information. Years of surfing (the web) have helped to develop my trust in certain sources. I agree with this CNN health article offering "Tips for Savvy Medical Web Surfing" and tend to steer clear of all the latest wonder drug and herb websites.
"Scientific" research can be slanted to the benefit of the funding source or researcher, to the same degree as the latest and hottest diet guru's claims. We're aiming for self-responsibility here, so if what you read sounds true for you, consider it and try it. If not, sigh (but with a deep exhalation) and know that I meant well. :D
THE BENEFITS OF DEEP BREATHING:
1. Promotes Relaxation. Taking deep and slow breaths, is the quickest way to trigger your parasympathetic nervous system into the relaxation response.When we're stressed or frightened, our breathing is shallow and rapid (among other physical responses) and we're ready to fight or flee. When the stressor is gone, we breathe a sigh of relief and the brain receives signals that say, "All is well".
2. Eliminates Toxins. Your lymphatic system relies on body movement to flush out cellular waste and toxins. The action of your diaphragm in deep breathing massages your inner organs and stimulates lymphatic flow, much like the way your heart pumps blood through your body.
3. Improves mental clarity and relieves the effects of depression and anxiety. Much in the same way that it promotes relaxation.
4. Burns Fat. When you exercise, too fast or too slow, your body doesn't receive enough oxygen and burns glycogen rather than fat. Deep breathing strengthens your cardiovascular system so that you're able to exercise aerobically, and efficiently burn fat.
Illustration: USC Health Magazine
Resources: (1) Marcelle Pick, Deep Breathing - the Truly Essential Exercise, Women to Women. (2) Renew-You.com, Fitness Habits - Nurturing Ourselves Through Movement.