i got my PM 5 years ago at age of 46 for slow heart rate. I’m a runner and have had the rate responder adjusted three times because about 8 mos after an adjustment I begin to feel gassed out during my workouts. Last week the tech told me she adjusted the rate responder to its max setting. I am still feeling winded during slight exertions. Anyone else experienced similar condition? Also, read a posting about thumping the PM to make the accelerometer more responsive during workouts. Does this work for all PM models? thanks!