What does a drop of >20 mmHg systolic or >10 mmHg diastolic during an orthostatic blood pressure measurement indicate?

A drop of more than 20 mmHg in systolic blood pressure or more than 10 mmHg in diastolic blood pressure during an orthostatic blood pressure measurement is indicative of hypotension. This significant drop typically occurs when a person transitions from a supine to an upright position, leading to a decrease in venous return to the heart and, consequently, reduced cardiac output. The body normally compensates for this shift through various mechanisms, such as increasing heart rate and constricting blood vessels to maintain blood pressure.

When these compensatory mechanisms are insufficient, the person may experience symptoms such as dizziness, lightheadedness, or even fainting due to inadequate cerebral perfusion. Identifying this condition is crucial as it can reflect underlying issues, such as dehydration, blood loss, or autonomic dysfunction. Understanding this response to positional changes in blood pressure is vital in clinical practice to assess patient status and guide appropriate interventions.