a mule deer wakes up and it knows it must outmaneuver the fastest mountain lion or it will be killed. Every morning in Idaho, a mountain lion wakes up and it knows it must outmaneuver the slowest mule deer or it will starve. It doesn't matter if you're the lion or the deer, when the sun comes up, you'd better be able to move quickly and skillfully.
For wild animals that are inexorably linked to the food chain the difference between being "in shape" and being "out of shape" is the difference between life and death.
For humans it is no different. If you want to stay young and alive you'd better be moving...Everyday !!! Fast movements, slow movements, high tension, low tension, up, down, side to side, move your body and make the animal inside you smile.
Too many people take better care of their cars, "stuff" and animals than their own bodies. Like it or not you are not that evolved...You are still an animal and when the sun comes up you'd better be moving :)