8 points to your reading.
if your arm hangs by your side or you must hold it up while getting a reading, your blood pressure numbers may be 10 points higher than the actual figure. your arm should be on a chair or counter so that the blood pressure cuff is level with your heart.
having the cuff placed over clothing can add 5 to 50 points to your reading. the cuff should be on a bare arm.
a too-small cuff can add 2 to 10 points to a reading.
talking can add 10 points to your reading. remain still and silent while your blood pressure is taken. 