Orthostatic hypotension 

drop of SBP by 20mmhg or diastolic by 10mmhg 

5 different types of orthostatic hypotension 

Classic - within 3 minutes of standing 

Delayed - after 3 minutes of standing 

Initial - lasts less than 15 seconds after postural changes

Delayed blood pressure recovery - blood pressure drop that returns to its original values at a time longer than 15 seconds.