Comparisons of normal responses to the tilt (control), orthostatic hypotension (OH), and orthostatic cerebral hypoperfusion syndrome (OCHOs). Normal heart rate increment (≥10 and <30 BPM) is seen in all examples. Orthostatic blood pressure is stable in a healthy control subject and OCHOs while it is reduced in OH. Orthostatic cerebral blood flow velocity is stable in a control subject and reduced in OH and OCHOs. CBFv can be normal or reduced in OH, depending on functioning of cerebral autoregulation and severity of OH. Green boxes represent mean blood pressure obtained from the upper arm. HR = heart rate, BP = blood pressure, and CBFv = cerebral blood flow velocity.