it is simple gravity. the most accurate bp reading is with your arm at heart level. when you raise it above your head you will get a falsely low reading because your heart has to pump the blood higher.
why do i get a normal bp reading with my arm resting on my head? . if i take my bp in the recommended position it is always high. if i rest my arm on top of my head my bp is normal. can you tell me why and would this be a true reading?