The most tiring sport is Mixed Martial Arts. People think fighting isn’t a good source of fitness, but the truth is that M.M.A. is one of the most physically demanding sports in our world. If you are afraid of joining a fight club or a dojo then the best alternative is setting up your own punching bag. Setting up a bag is fairly cheap and doesn’t require alot of effort to put up. The results are worth the effort of setting up the bag, but I suggest to join a fighting dojo so you are learning while working out. Hangup a bag, and send me some pictures of your set up.
P.S. Don’t get cocky after hanging up your own bag, fighting is more than knowing how to punch something that doesn’t fight back.