Hypotension is an abnormally low blood pressure. This can occur for many reasons, however the most common causes include shock and medication side-effects.
Symptoms of hypotension include weakness and dizziness (especially positional or orthostatic dizziness).
There is no strict definition of which exact blood pressure level is considered “hypotension”, however in general if the systolic blood pressure is < 90 mmHg or the diastolic < 60 mmHg, then hypotension is thought to be present.
Normal, young healthy individuals commonly will have blood pressures around 90/60.