At the time I found yoga, my pulmonary function was at 36%, my Psoriatic arthritis wasn't too bad, but my fibromyalgia and Raynaud's were making life difficult. Shortly after starting yoga, using a book I found in a bookstore, I noticed quite an improvement in the Raynaud's; I assumed due to the increased circulation. After nine months, a recheck of my PFT showed 96%, my doctor was overwhelmed, saying 5at it was an incredible turnaround, and great for anyone let alone for a 43 yo asthmatic with an underdeveloped lung ! My rheumatologist is adamant about the benefits of yoga for arthritis. It has the added benefit of quieting my mind, a few poses before bed and I sleep much better. The practitioner has total control over how they practice; gentle, or degrees of strenuous. Just the fact that one is getting in touch with how their own body works, and feels, is empowering because they know that they are at least acting to take control of their health.