Low Blood Pressure (Orthostatic Hypotension)
What is orthostatic hypotension (low blood pressure)?
Orthostatic hypotension is a sudden drop in blood pressure when you stand from a seated or prone (lying down) position. You may feel dizzy or even faint.
Orthostatic means an upright posture. Hypotension is low blood pressure. The condition is also called postural hypotension.
What is blood pressure?
Blood pressure measures the force of blood against artery walls as the heart pumps blood through the body’s circulatory system. Blood pressure includes two measurements. Each is calculated in millimeters of mercury (mmHg):
- Systolic: Arterial pressure when the heart beats and fills arteries with blood.
- Diastolic: Arterial pressure when the heart is at rest or between beats.
Your healthcare provider records blood pressure as systolic over diastolic. Healthy blood pressure for most people is below 120/80 mmHg. A reading below 90/60 mmHg is considered low blood pressure.
Healthcare providers define orthostatic hypotension based on individual blood pressure. You have orthostatic hypotension if your blood pressure drops more than 20 mmHg in systolic pressure and 10 mmHg in diastolic pressure within three minutes of standing up.
Who might get orthostatic hypotension?
Anyone can get orthostatic hypotension. The condition becomes more common as you age. These factors increase the risk:
- Anemia or vitamin B12 deficiency.
- Dehydration from diarrhea, vomiting or diuretics.
- Endocrine problems, including diabetes, thyroid disease and Addison’s disease.
- Heart conditions, including arrhythmias and heart valve disease.
- Medications for high blood pressure (hypertension), heart disease and depression.
- Neurological problems, such as Parkinson’s disease and dementia.
- Pregnancy, especially during the first 24 weeks of pregnancy.
- Prolonged immobility due to illness, including pregnancy bed rest.
Are orthostatic hypotension and postural tachycardia syndrome (POTS) the same condition?
Postural tachycardia syndrome, or POTS, causes symptoms similar to orthostatic hypotension. Both cause dizziness or fainting upon standing. Along with a drop in blood pressure, POTS causes a heart rate increase of 30 to 40 beats per minute within 10 minutes of standing. POTS is less common than orthostatic hypotension.
What causes orthostatic hypotension?
When you’re seated or lying down, blood from veins in your legs flows easily to the heart. When you stand up, blood in your lower extremities has a harder time reaching your heart. There’s less blood available for your heart to send to organs and muscles. As a result, blood pressure temporarily drops.
What are the symptoms of orthostatic hypotension?
Orthostatic hypotension happens more frequently — and with more severe symptoms — in the mornings. That’s because blood pressure is at its lowest in the morning.
Some people don’t experience any symptoms from orthostatic hypotension. Others find that hot temperatures (from the weather, a fever or even a hot tub or shower) make symptoms worse.
Other signs include:
- Blurred vision.
- Chest pain, shoulder pain or neck pain.
- Difficulty concentrating.
- Fatigue or weakness.
- Heart palpitations.
- Nausea or feeling hot and sweaty.
- Shortness of breath (dyspnea).