I'm out of shape. I'm the kind of person who usually spends almost 10 to 16h a day in front of the computer nowadays but in the past I at least experienced or practiced about 10 different martial arts styles and tons of other sports. Thanks to my sedentarism nowadays, besides losing most of my muscles, I lost elasticity and good part of my health. As I was also a smoker during this period (thankfully I stopped this April and now have an aversion towards cigars) I have no stamina whatsoever thanks to that, a few problems with my joints, specially the knees that hurt even when idle, there are not many exercises or routines I know of that I could do without feeling like I'm about to die in a few seconds after I start, besides dizziness and a lot of nausea, sometimes even vomit (yeah, it's that bad and that's just the start).
My question is, does anyone know of really low impact exercises with a slow progression routine towards more normal ones?
My objectives are to develop strength, speed, stamina, and elasticity. I don't care about growing muscle; I want to be able to practice and perform the martial techniques I remember, and to learn a bit of "tricking".