Beth,

Kudos..keep up your good exercise work!

Recommend you consider a weighted vest to leverage the aerobic benefit of your daily walks.
Pls see link below and you can read some of the user reviews (94% favorable)

Ida bought one six weeks ago (she can't run anymore due to knee challenges, and to prep her for our annual Dolomiti hiking trip in Sept) she loves it and uses it (everyday when doing yardwork) and uses it (she is now up to 12lbs) with her 50 min walks with our four pups in early a.m before she goes to work...our neighbors who also walk were very curious, now two neighbors have bought a weighted vest.

A weighted vest is a great way to leverage your
exercise time, burning more calories and toning muscles.

http://reviews.walmart.com/1336/5481392/reviews.htm