Its simple, it takes as long as it takes, but is useful if you want to do a cardio session with a bit of childish fun.
The problems: if you live in a bungalow, or if its really windy (actually it could make things a bit more interesting)
Laminate a piece of brightly colored A5 paper, now go up to your bedroom window, start a stop watch and throw it out, run down the stairs, out the door, get the card and return to the starting point, repeat 50 times, record your overall time, repeat again when your bored of your normal routines.
Remember, have fun, be young in your mind!!
Chris Nash
PT Fitness