Hi, everyone. I am not a regular on this board but I was intrigued by the question. I just had a discussion about this on another board.
It has been my experience, like Mayness says, that as you lose weight and get more fit you will be able to go further and/or faster. It always depends on what your goal is. I use the cardio portion of a book called Fit For Life by Bill Phillips. My favorite quote from the book is: "Many "fitness experts" recommend that as soon as you can exercise for 30 minutes "comfortably," you should increase to 40 minutes, Then 60. Then 90...What's the objective, to eventually work out all day?" So he designed a program that lets you workout for 20 minutes at a time but with increasing intensity.
The book gives you a 20-minute interval cardio program. Meaning you walk/run for one minute at a moderate pace and every minute for four minutes you up your pace. The fourth minute you are kind of pushing yourself. But remember this is only for one minute. You do this for 20 minutes. As you continue to work out your old moderate pace will become slow to you. At this point you need to up your moderate pace. You will actually start to go further in those twenty minutes.
I started out walking 2.7-2.9-3.1-3.3 MPH on a treadmill 2 months ago. Now I am doing 3.6-3.9-4.3-4.6. The 4.3 is a slow jog and 4.6 a little faster but I'm doing it for two straight minutes. I usually adjust my pace after 2-3 weeks.
Remember you are working out at your pace and you will get faster as you lose weight and get more fit. Good luck.
