Elevating your feet will not lower blood pressure and will actually increase the blood pressure reading when your feet are higher than your heart. On the other hand, if you are doing activities to relieve stress such as yoga (which often elevates your legs, such as legs-up-the-wall pose), then over the long run, these stress reducing activities may help to decrease your blood pressure (but it is not the act of elevating the legs that is lowering the blood pressure it is the stress relieving activity).