I am male, 62, 33 BMI, cholesterol of 120 and LDL of 35 (yes), diagnosed with PVCs, passed a stress test last August, and 3 mos ago retired. I do cardio on an elliptical trainer 30-35 mins five times a week, starting at 140 steps/min and increasing by minute 30 to 190+. My heart rate starts at 78 and moves to 100 in 2-3 mins, but here's the problem: if I push my heart rate to over 120 in less than 10-15 mins, it jumps and registers 190 on the HR meter on the machine. It feels like a PVC outburst; I can even feel it coming. If I try to keep going on the elliptical, I feel tired and weak and cannot maintain a pace over 150 steps a minute. If i get off, the PVCs stop in 5 mins and I can do weights, etc (at a heart rate of 100-115); but if I get back on the elliptical and get my heart rate over 120, it jumps again to 190. Some days I am very patient and keep it under 120 until 20-25 mins into my routine, and then I can take it up to 130 even 138 by minute 35. But I am frustrated because I am not able to work out as much as I want and get into shape as much as I want. Even 9 mos ago I did not have this problem -- I would do 30 mins a session 5 times a week and within a few weeks was able to get the heart rate to 120 in <5 mins and keep it between 120 and 140 for another 30 mins; no longer, even though I have been working out for 4-5 weeks at this pace. What should I do?