good question, and the same what everyone else would ask... I play for 45 min or more, but im mostly just walking around after 15 min. I don't know who told you that you "can't" play football when you have CFS, but perhaps I shouldn't? Keep in mind I "was" a very fit person before I got CFS, but obviously that has changed although having CFS is NOT the same as being unfit. The reason why I choose to play, is because it is one a decreasing amount of joys I have, and I love the game. After playing, I feel devastated, but I can't just sit home contstantly.
I have a home job, and I choose my own hours, so that helps me a lot in staying on top of it. I'm sure there are many who have much more critical CFS conditions than me.
Just for the record, when talking about "football", I mean the European game, which is called "soccer" in the US.