Sudden changes in posture cause homeostatic imbalance, and stimulate the cardiovascular system and the sympathetic division of the autonomic nervous system to respond in order to correct the imbalance. Standing quickly causes blood to pool in the lower body which makes blood pressure drop. This stimulates the baro-receptors in the large arteries such as the aorta and the carotid bifurcation to send signals to the Medulla Oblongata in the brain (Lanier, Mote & Clay, 2011) & (Ziegler, 1980). In response to these signals the Medulla Oblongata sends messages through the sympathetic nervous system to the body to create responses such as vasoconstriction (constriction of the blood vessels) (Marieb, 2015). As well as vasoconstriction, increased cardiac