Low Blood Pressure (Hypotension): Symptoms, Causes, and Treatment
What Is Low Blood Pressure?
Hypotension is the medical term for low blood pressure. You have it when a reading shows your blood pressure is much lower than expected.
A blood pressure reading appears as two numbers. The top number is a measure of systolic pressure, or the pressure in the arteries when the heart beats and fills them with blood. The bottom number measures diastolic pressure, the pressure in the arteries when the heart rests between beats. The optimal blood pressure level is less than 120/80. (You may also see it written as 120/80 mmHg).
What is considered low blood pressure?
Doctors consider you to have low blood pressure when your reading is less than 90/60.
The risk of both low and high blood pressure increases with age due in part to normal changes during aging.
Is low blood pressure serious?
In healthy people, low blood pressure without any symptoms isn't usually a concern and doesn't require treatment. But low blood pressure can be a sign of an underlying problem -- especially in older people -- and could reduce blood flow to the heart, brain, and other vital organs.
Long-lasting low blood pressure with no symptoms is almost never serious. But you can have health problems when your blood pressure drops suddenly and your brain doesn't have an adequate blood supply. This can lead to dizziness, lightheadedness, and sometimes fainting.
Types of low blood pressure
There are several types of low blood pressure:
- Postural hypotension. Sudden drops in blood pressure most often happen when you rise from a lying or sitting position to standing. This is called postural hypotension or orthostatic hypotension. It happens when your cardiovascular or nervous system doesn't react appropriately to sudden position changes. An estimated 10% to 20% of people over 65 have postural hypotension.
- Neurally mediated hypotension. You can get this type when you stand up for a long time. It's thought to happen because of communication problems between your brain and your heart. It's more common in younger people.
- Postprandial hypotension. Sometimes, your blood pressure drops an hour or two after a meal. It’s thought to be caused by blood pooling into the vessels of the stomach and intestines. It's most common in older people with high blood pressure or nervous system conditions like Parkinson's disease. It tends to happen after large meals containing lots of carbohydrates.
- Multiple system atrophy with orthostatic hypotension. This rare type of low blood pressure happens when you're lying down. It involves your involuntary nervous system, which controls things like your blood pressure, breathing, and heart rate.