So like 10 minutes... 3 times a day?
More like 20-30 minutes. Walk a minute, sprint for 2, then repeat.
It's like something called HIIT. Do a google search. It forces your body to burn calories at a fast rate. If you do continuous cardio for prolonged periods, your body senses a state of famine and reduces your metabolism. If you go long enough, your body may even burn muscle and fat.
However, if you're really out of shape, HIIT is not for you. You need to be in decent shape to do it safely.
In that case, do eliptical machines and keep your HR between 140-160 for like 40 minutes a day. No breaks.