How much should your heart rate increase from sitting to standing at 21 year old male?

Less than 10: Change in position triggers the carotid baroreceptors to gently change hr in order to stabilize BP from effects of gravity. Normal bp/hr fluctuations should be less than 10 points unless dehydrated, over medicated, or suffering from neurally mediated dysfunction (abnormal reflex arc between the baroreceptors, the brainstem, and the heart).