Sedentary lifestyle?  Do the following steps to presto change-o!:

1)  Find a kitchen island with ample room to run around
2)  Have a dog that will follow you, especially as you run faster and faster
3)  Have at least one more person trying to catch a glimpse of the dog as the dog chases you while you run away from the dog
4)  Repeat until exhausted/breathless from laughter