heart rate when you started out and exercise?

I never noticed any significant change from doing a new workout routine, but I did notice an overall change after I went from completely sedentary to working out in general. Before I started doing any exercise (and was about 130 lbs. heavier than I am now), my resting heartrate was around 60-65. Now that I exercise regularly, and have done so for 3 years, my resting heartrate is around 50-55.

I have no idea about the answer to your second question, but I'd love to know. I am constantly trying to get my heartrate up during exercise, but I just can't seem to do it. Even when I'm sprinting and feel like I'm about to pass out from the exertion, my heartrate never goes above 152 (that's the absolute highest I've ever gotten it, according to my HRM), and usually maxes out at about 147. On a typical run (3-5 miles at about a 10 min/mile pace) where I'm feeling like I honestly can't push myself any harder, I'm averaging about 128.

I have looked at some of the "calories burned by heartrate" calculators, and they all have a VO2MAX figure that they factor into the equation -- my VO2MAX is 51, so I do burn significantly more calories in the same amount of time than someone with a lower VO2MAX rate. http://www.shapesense.com/fitness-exercise/calculators/vo2max-calculator.aspx