Not one to reply but saw this and could not resist. I was diagnosed with CF at age 2 and have always been very active: gymnastics, horse back riding, cheerleading, martial arts and powerlifting. I started Powerlifting in 1991 at Western Illinois University where I also met my now husband for 20 years. From the very first day I walked into the Salvation Army (where our team lifted) the coaches Judy and Roger Gedney stated that I could be ready to compete at State. I competed in State and won! That was all it took and I was hooked! I went on to compete at the State, National, Collegiate, Police and Fire and even Worlds winning each one. I also established records in three weight classes 111, 116 and 122 lb. I also received Best Lifter in several competitions beating out some of the heavy weights.
I tell you this because Powerlifting according to my doctors saved my life due to all the muscle mass. I had a double lung transplant in 2004 and immediately following I ran into some complications and got down to 62 lbs. During the 2 in a 1/2 years I waited for the transplant I did my best to maintain my physical well being even while on oxygen I went to the gym. My suggestion to you if you can is to incorporate weight training, Powerlifting or Weightlifting (all three are different) into your daily workout. Powerlifting consists of three lifts: squat, bench and deadlift. Weightlifting involves the snatch and clean and jerk (also performed at the Olympics), did this as well. If you are not familiar with these lifts seek a professional coach or trainer (CSCS certified or equivalent). These lifts will help you gain muscle mass but again...if you don't know how to perform the lifts correctly they could do more harm than good.
I was fortunate to have coaches that were known in the world of Powerlifting. I also have a husband who went on to not only get his CSCS*D, CPT*D, Certified Weightlift Coach but also his doctors degree in the field of Exercise Science and who has written several books, published articles and journals for NSCS.
I am by no way trying to brag. Growing up I was told time and time again I could not do something because I have CF. I am here to tell you if you want something in life there should be nothing stopping you including CF, Asthma, Transplant and Cancer (all of which I have). Wishing you the very best!