I am very very out of shape. I recently found out I have a right bundle branch block, but when I went into the cardiologist, he pretty much said it was nothing to worry about without even doing more then an ekg. I have been living an EXTREMELY sedentary lifestyle for about 3 years now. If I do something simple like carry something heavey inside from the car, I noticed my heart rate gets up to about 165-170 BPM and I get a little winded. It goes away quickly if I sit down but is this somthing serious to worry about? Should I get back into the cardiologist?