I also have the double F508 mutation. I was not diagnosed until I was 12. My first IV treatment was when I was 25. I have only had 2 IV treatments since. My FEV1 are not the greatest but I know I can improve them. When I was in my teens I ran cross country, 30 to 40 miles a week. I was never sick. When I went to college I got lazy and stoped running. Bad Idea! Now I am trying to make up for it.