A lot vs. Alot: 9 Grammatical Pitfalls
low blood pressure occurring upon standing up or when standing, often accompanied by faintness, dizziness, and vision disturbances; also called postural hypotension
When a person experiences any of the symptoms above, a physician can confirm orthostatic hypotension if the person's blood pressure falls significantly on standing up and returns to normal when lying down.
orthostatic hypotension n.
A form of low blood pressure precipitated by moving from a lying or sitting position to standing up straight. Also called postural hypotension.