I learn for 1 hour in the morning. and 1 hour in the evening however i am overweight and want to go to the gym.
i want to know if exercising in the evening instead of learning is bittul torah and a bad plan.
I commend you that you asked such a question. this shows that learning and ruchnius is important to you. I don’t know your situation well, but it would seem that you would be better off keeping your learning time and not letting other things get in it’s way. The yetzer hora will do whatever he can to get us to stop our learning seder, because he knows that this is the foundation to everything else, and to your overall level of yiddishkeit. On the other hand it is important for you to exercise. Try to find some other time that you can exercise, maybe after you learn, on Sundays etc.
May H-shem give you a lot of siyata dishmaya in your learning, business, family and your health.