The human body is designed to be mobile. As my grandfather often used to say, "use it or lose it." When I consider that at ninety years old, he was still logging about five miles a day on his walks and nature explorations, there was more than a bit of truth in that statement!
While there is no "ideal ratio" for everyone, keep in mind that movement is good for both the body and the mind. Rest when you can; move when you must (or when the spirit moves you
)
Anecdotally, I work in a field where I'm on my feet and on the move for ten to twelve hours a day. Proper footwear, practicing good ergonomics when bending and lifting, stretching, and having good posture have all helped to protect my feet, knees, and back from the demands of my work.
I also walk several blocks to and from either the bus stop or the garage on the days that I drive into work(I take the stairs in the garage; the bus stop is an uphill walk from my house),live in a multistory house, and enjoy being physically active for pleasure, so movement is just part of my daily routine.
In a nutshell, Luciano, you're better off spending more time on the move than sitting for long periods of time.