By regular *slow* practise of tai chi and chi kung, your stamina will improve. This was demonstrated this week by students in two different classes that I teach: One was sweating after doing slow tai chi form, and the other was surprised how much work he was doing in the chi kung sequence, since it just seemed like a bunch of slow easy movements...

When you look at the stereotypical people doing tai chi or chi kung in the park, it looks like nothing, because it's all slow motion. But it's the slow motion, together with bending the knees, that will really make you sweat,  improving your stamina over time.

After some time at regular practise, you should feel your energy and stamina revitalised. Indeed, you can have days that drain you totally, then come and do some tai chi or chi kung, and feel uplifted by raised energy levels after that.

Keep on practising and enjoy the effects!