What is it called when your heart rate goes up a lot when standing?

Can be normal: Typically your heart rate will rise by 20 to 30 bpm, when you first stand, from a lying or sitting position. This is a response that keeps the blood flow to your brain, as your circulatory system compensates for the changes with gravity. Your HR should normalize after 1 to 2 minutes of standing. If it doesn't we call it an abnormal orthostatic response (e.g. POTS, orthostatic hypotension . etc)