I just joined a gym last week, and so far I have been good... 45 minutes on the elliptical, weights, abs class, and stretching every weekday (yes, I still have too much time on my hands). What I'm wondering is how to judge how much to push myself as far as cardio is concerned. So far I have kept a close watch on my heart rate, and kept it over my target number for 45 minutes, but I feel like I'm going really slow! I know I'm out of shape, but wow! Does anyone else base their speed on heart rate? Is it the way to go?