I was in my mid-20s and just getting into cycling when I started to get short of breath after really intense rides or going up big hills that before then I could just muscle up (full disclosure I had no idea what I was doing then). As it happens, it turns out I had a malignant tumor in my right lung. The docs didn't even think I was going to survive -- they all said I had at most five years to live. Happily, almost 25 years later, I'm still here, though I have but one lung. I definitely run into problems on the bike sometimes, particularly when I get a cold or allergy (cats kill me) and it's really hard for me to climb above only 1000-feet. I was told that the main problem is my inability to exchange air, that having just one lung makes it harder for me -- even though I use a lot more of my one lung that most people use of both of theirs (present company excluded I imagine).

However, I've been trying to do some research on it and have posed the question of whether I can improve my breathing and climbing and my intake/outtake through training. Looks like I'm going to get to go to a cycling camp in central California next year and my goal is to learn better ways I can use my one lung. I will say that despite being a bit of a wuss, I've climbed higher and ridden farther than I ever thought possible, having spent much of the first 15 years after having Cancer exercising like I had half a lung. I'm sorry it took me so long to realize I can do things I previously thought impossible.