Postural hypotension is the occurrence of low (systolic) blood pressure when standing up too quickly from a reclined position, causing fainting or lightheadedness. For most people, a systolic pressure less than \(90 \mathrm{~mm} \mathrm{Hg}\) is considered low. If the blood pressure in your brain is \(120 \mathrm{~mm}\) when you are lying down, what would it be when you stand up? Assume that your brain is \(40 \mathrm{~cm}\) from your heart and that \(ho=1060 \mathrm{~kg} / \mathrm{m}^{3}\) for your blood. Note: Normally, your blood vessels constrict and expand to keep your brain blood pressure stable when you change your posture.