I am an ex college football player, who became a personal trainer shortly after. I do not work out as often anymore and have started a family and now have a pretty normal dad bod, well toned and defined dad bod. Whenever I take my blood pressure my arm is usually slightly bent to rest on a table, as my Dr. would always tell me to relax, which i thought meant let your arm stay slightly bent at the elbow but fall limp on a surface. I always wondered if the flexed Bicep interfered with readings which would very often be high. Well today I tried just out of curiosity straightening my arm and letting my bicep stretch while running the test. The readings were wayyyyy lower like 30 points lower than when they were taken a few hours earlier when my arm was partially flexed due to being in a chair and resting my arm on a table. I went to the ER worried about the sudden drop. The Dr and Nurse working the ER had me lay down and monitored my blood pressure while my arm was mostly straightened position(biceps stretched triceps engaged) vs resting on a table(biceps engaged triceps stretched). Again the tests were a lot better. I am beginning to think that having your arm rest on a table and get a sky high reading vs having your arm straight and getting a normal reading.