Orthostatic Hypotension The signs and symptoms of orthostatic hypotension may happen within a few seconds or minutes of standing up after youâ??ve been sitting or lying down. You may feel that youâ??re going to faint, or you may actually faint. Signs and symptoms include: Dizziness or feeling lightheaded. Blurry vision. Confusion. Weakness. Nausea (feeling sick to your stomach). ...