Your Pulmonologist would be the one to refer you if you're seeing one, or else a primary doctor. I went to a cardio-rehab program at a local hospital that was very useful after a traumatic chest injury. There were patients on oxygen in wheelchairs. There were exercises they would do to build up muscle mass, and classes to help with breathing techniques that helped them expand their chest muscles. It was nice to see them gain confidence, and improve. Some graduated from the wheelchairs to some walking. An instructor had had a heart transplant, and taught the harmonica method he used during recuperation that helped get oxygen to his lungs. They monitor oxygen, and your heart during exercise. Go for it! They would evaluate you, and then determine if it would be helpful. I'm not sure if they base eligibility on a 5-minute walk test, and PFT testing.