Fitness Videos - Not huffing, puffing or sweating

When I do my WATP workout. I try to not step too hard since I live above someone so I'm probably not working as hard as I could. However, my buns and thighs do feel sore after doing enough knee raises and kicks. Should I be concerned that my heart rate isn't being raised enough?

I am the same way. I have actaully started jogging instead of walking on my 2 mile express workout and I sweat and my heart rate goes up!