Quick GuideBalance Disorders: Vertigo, Motion Sickness, Labyrinthitis, and More

In individuals who are dehydrated or anemic, blood pressure readings may be normal when they are lying flat; however, the lack of fluid is unmasked when they stand up quickly. The lack of blood to the brain may cause dizziness and lightheadedness. This feeling may pass in a few seconds as the body adapts. However, if dehydration or medications (for example, beta blockers) prevent the body from reacting by constricting blood vessels and increasing the heart rate, the dizziness may persist to the point at which the patient passes out (faints, or experiences syncope).

Some diseases are associated with an inability to compensate for changes in body position (autonomic dysfunction). Normally when a person stands, blood vessels contract to increase blood pressure slightly, and the heart rate increases to pump blood uphill to the brain against gravity. In autonomic dysfunction, a person may become dizzy when they move from a lying position to sitting or standing up. Examples of these diseases include diabetes, Addison's disease, or Parkinson's disease).

Orthostatic hypotension is a common symptom with Shy-Drager syndrome. Shy-Drager syndrome is a rare disease in which the autonomic nervous system degenerates and cannot provide the routine control mechanisms for the body including heart rate, blood pressure, and bowel and bladder function.

High blood pressure, or hypertension, is known as the "silent killer" since it often has no symptoms, even if blood pressure readings are markedly elevated. On occasion, a person may complain of headache, nausea, or dizziness, although the complaints don't necessarily correlate with the degree of blood pressure elevation.

However, if the blood pressure is elevated and the person has symptoms, there is a need to bring the blood pressure under control relatively quickly. The more severe the symptoms, the quicker blood pressure control needs to be achieved. For example, if a person is having chest pain or stroke symptoms associated with high blood pressure, the blood pressure needs to be controlled immediately (hypertensive emergency).