mine is high so I did a bit of reasearch. the #1 mistake made in the doctors office when it comes to bp is "misscuffing". the cuff your doc or nurse is using is for arms up to 13 inches. last time I had mine checked...I told her to do it again using a large cuff... 20 points difference. I know several guys who have there own "home" monitor (myself included) just make sure you purchase a large cuff to go with it.
If your arms are not at least 13 inches...get to the gym! lol