my husband and I LOVE THE Precor EFX 546i elliptical and was wondering if it has interactive heart rate programs? I use the heart rate handgrips on it all the time but I still have not figured out how to use the polar wireless chest strap in order to control the resistance level based off my target heart rate zone. For example, on many cardio machines such as elliptical units and treadmills, there are interactive programs that allow the user to vary the resistance according to their pulse. For instance, lets say Joe Smith sets his target heart rate to 130. When he is exercising on his elliptical, the resistance will insrease or decrease based on what John’s heart rate is at that moment. So, if John set his target heart rate to 130 and he was at 160 bpm, then the resistance of the elliptical would decrease so John would not be working out as hard, in turn, lowering his pulse. On the other hand, if John starts taking it easy, and his pulse falls to a calm 80 bpm, then the intensity of the elliptical will pick back up in order to get your heart rate back up.