If arm is extended and not supported, client may perform isometric exercise that can increase diastolic pressure 10%. Placement of arm above the level of the heart causes false-low readings. Placement of arm lower than the level of the heart causes false-high readings. Even in the supine position a diastolic increase of as much as 3 to 4 mm Hg can occur for each 5 cm the arm is below the level of the heart (Netea and others, 2003)