re really low impact, you actually do break a bit of a sweat and I was surpised to see the other day that when I did the 5 mile walk
using my heart rate moniter, I burned about 550 calories
without feeling like I exerted myself too much. I got mine from overstock.com and amazon because they seem to have the best selection and prices. My personal favorites are the 3 mile weight loss walk (pink cover) and the 5 mile walk.