After many years of cycling, I was riding 200km Audax event when I started getting breathing problems on the hills and had to slow down. I went to my GP and was asked to have a chest X ray and this showed a dark area at the base of my right lung. I went for some treatment at my local hospital and they could not find how this had happened. However after telling them about all my long distance cycling, one off the doctors said the stress of cycling could have caused the fluid build up. I was wondering if anyone else has had similar symptoms and been told it many have been due to cycling.