Answer from Alicia Wassenberg: Using a heart rate monitor can really enhance your workouts, especially if you are interval training. For intervals, you may want to work at 60-70% of your max heart rate (mhr)in the "valleys" and 80-90% mhr in the "peaks". To find YOUR maximum heart rate use the formula 220-your age = mhr. The monitor will help insure you are in the right place at the right time. If you are trying to stay in the "aerobic" zone (working with oxygen) usually 65-85%, a heart rate monitor will keep you in check from getting your rate too high, say 90%+, which would be anaerobic(without oxygen). Also, most cardio equipment can "sync" up with heart rate monitors as well, so you don't have to use the hand grips on the machines, leaving you hands free, which is great if you are running on a treadmill. If you aren't sure and not quiet ready to make an investment, ask a trainer/instructor at your club to loan you one for a few workouts for a "test drive".(Another great use for monitors is during pregnancy, you can keep your heart rate at at safe rate for you and baby, check your OB/GYN for safe rates to work at). Have a great workout!!