Hi mzzleolady234,
Thanks for writing and welcome to the alli community! It sounds like you're really benefiting from increasing the intensity of your workout by adding in hills to your workout! Any time that you increase speed or resistance to your workout, you burn more calories and begin to increase your fitness level by challenging your cardiovascular fitness!
The additional benefits are as you stated! Nice firm and strong muscles! Continue to challenge yourself each week by incorporating new fitness goals and challenges. Begin to add in 2-3 minutes of jogging/running while you're out for your walk, run up the hill, etc. I would also encourage you to begin to include strength training into your weekly regimen. By doing so, you'll become metabolically more efficient b/c muscle requires more energy to function than fat! Therefore the more muscle vs. fat you have, the more calories you'll burn all day long, even while at rest! The alli website provides helpful, animated demos for a full-body workout! Try to perform ST 25-35 minutes per session, 2-3 times per week! You'll really love the esthetic benefits it will provide! You'll begin to see long, lean shapely muscles!
Work hard and stay positive!
Kelli