What causes low blood pressure?

By Jayne Morgan, M.D.
Executive Director of Health and Community Education

You’ve probably heard of hypertension, or high blood pressure. You also know high blood pressure is not very good for you. But did you know low blood pressure carries risks as well?

What is low blood pressure?

For most adults, a normal blood pressure is usually less than 120/80 mm/Hg. Low blood pressure (or hypotension) is generally anything below 90/60 mmHg.

Some people have low blood pressure all the time and it could be normal for them. It could also be a sign of other serious medical problems.

So, how do you know the difference between "normal for you" and a medical problem, and when should you worry? Generally, it's not a problem if you're healthy and show no signs or symptoms of low blood pressure, such as:

• Dizziness

• Fainting

• Blurred vision

• Lack of concentration

• Depression

How common is low blood pressure? 

This is a difficult number to gauge as hypotension can be common without any symptoms. Postural hypotension, or POTS, becomes more common with age. It causes dizziness when you go from a lying or seated position to a standing position. Approximately 10 to 20% of people over the age of 65 have some form of this.

What causes low blood pressure?

There are many causes of low blood pressure, especially if you are symptomatic. These include:

• Heart problems

• Hormone imbalances (such as thyroid disease, parathyroid disease or Addison’s disease)

• Medications (such as beta-blockers, ACE inhibitors, diuretics, some antidepressants and Viagra)

• Side effects of medications can cause lightheadedness. Talk with your provider if symptoms occur after a new drug or dosage.

• Parkinson’s disease (the disease itself, as well as the drugs used to treat the condition)

• Spinal cord injuries

• Sepsis/infections

• Dehydration

• Nutritional deficiencies (such as B12 and folate)

• Stress

• Allergic reactions (anaphylaxis is the most severe form and can cause a dangerous drop in blood pressure)

• Pregnancy

• Advancing age and conditions such as Alzheimer's, liver disease, and Parkinson's can affect nerves that regulate blood pressure.

• Heat exhaustion or heat stroke

• POTS (postural orthostatic syndrome)

• Drop in blood volume (from trauma or internal bleeding)

Is low blood pressure contagious? 

No, you cannot pass low blood pressure to someone else or catch it from anyone.

How is low blood pressure treated? 

Treatment usually starts by finding out why it’s happening (especially if you are symptomatic), then addressing the underlying cause. The blood pressure generally autocorrects from there. The most important thing is to identify the underlying cause and correct it.

How to prevent low blood pressure

Well, it turns out that reducing your risk is easier said than done. Avoid factors under your control, including illicit drug use and supplements, remedies, or herbals that lower blood pressure.

Remember, low blood pressure (hypotension) can be just as dangerous as high blood pressure (hypertension). Stay in the know, focus on your better health and always seek medical advice for unexplained symptoms.

We make getting great health care simple and convenient. Schedule an appointment today through your Piedmont MyChart account or our website.