From no exercise 7 months ago, I am now doing 2 x 2hr karate as a beginner each week. It is physically demanding compared to my desk existence previously. If I keep it going how does the fitness work? Will I only ever get fit enough to do those sessions or is it cumulative, I.e. the more I do the more I will be able do?
Your body adapts to the demands placed upon it. So if you demand that it do 2 x 2hr karate sessions, it will get to the point where it can do that comfortably. It won't necessarily progress beyond that though. If you want to do that, you need to add extra stuff into the mix, and challenge yourself with different things. So now you get the fun of finding all sorts of other fun stuff to do Mitch
That's a smart question. Once your body adapts to the two hour sessions to a point where you can comfortably complete both classes during the week you can start pushing your self harder/faster/higher during the same two hours and again your body will continue to grow, that's the cool thing about martial arts.