Incorporate “intervals” into three or four of your treadmill sessions each week
Intervals are brief periods (about one minute) of more intense exercise mixed into your Treadmill sessions. For example, you would do a one minute interval of faster walking about every five minutes throughout your exercise session.
Here’s how it will look; you’ll start with your normal three to five minute warm-up and then five minutes into your walk you do your first interval, one minute of faster walking (or perhaps jogging). At the end of that minute you should be “winded” and ready to slow down. You’ll slow down to your normal walking speed for the next four minutes and then your fifth minute is another one minute interval. This pattern continues throughout your exercise session.