I am not a very sporty person but because of all the noise about the importance of exercise I did some reading on the necessity of movement. Our bodies are made to move in gravity, and the much-touted stand-up desk is not the cat's meow either if you stand still all the time.
Our current computer based work culture condemns us to sit for long hours, yet our bodies thrive on perpetual motion. Point in case - when your body aches you need to move more, not less. As a matter of fact, as little as walking briskly half an hour each day increases your life span supposedly by about seven years. The message of our overcompensating workout culture is to exercise vigorously at the gym. But that is not necessarily the best answer, unless of course you just love it and thrive on it - everybody has a different need for type and intensity of movement. Just don't sit for long hours without getting up and stretching often (long commutes are a killer...). Kids fidget and want to move naturally. Yet, we force them earlier and earlier to sit still. Fidgeting is the body's natural way to signal its need for movement.
We contract lawn mowing, house cleaning and house maintenance work out, yet, this all makes for excellent exercise. You don't need an expensive gym membership to move your body. Joan Vernikos, who studied the effects of zero gravity on the body for NASA, concludes in her book Sitting Kills "Standing up often is what matters, not how long you remain standing," at least 32 times a day she recommends. It is our interaction with gravity that's so important. The main message about movement is: continuously and gently, not seldomly but intensely.