Making sure you have a healthy blood pressure can be confusing. What constitutes pressure that's too high? And what does it mean when it's low? First, the good news. Blood pressure that's too low isn't usually a sign of something to worry about. As long as you feel well and aren't experiencing any bothersome symptoms--like dizziness or fainting--then the lower the better.

"In the United States, untreated individuals with the lowest blood pressure have the lowest risk of cardiovascular disease and death," says David Ellison, M.D., F.A.S.N., F.A.H.A., head of the Division of Nephrology and Hypertension at Oregon Health & Science University in Portland, Ore. "If you're not on medication and have low blood pressure--be happy, you're in great shape."

How low can you go?

Most of the time when you have low blood pressure you have good cardiovascular health, explains Dr. Ellison. But some people with low blood pressure experience symptoms. "In most cases, we just treat low blood pressure symptoms based on the cause. In rare cases, low blood pressure can be the sign of a serious, underlying disorder."

Linda Armstrong* of Portland, Ore., found out she had low blood pressure when she was pregnant, at age 28. Now 56, she has maintained her low blood pressure and has experienced a common symptom intermittently--fainting.

"When doctors take my blood pressure, they always tell me I'm in good shape," says Armstrong. "I have fainted four or five times, but never received treatment for this symptom or for low blood pressure."

In 2011, Armstrong was sitting outdoors on a bench and felt woozy. She fainted, hit her head on a cement sidewalk and ended up in the emergency room (ER). "My blood pressure was very low in the ER and they ran tests to see if there were any underlying disorders," recalls Armstrong. Fortunately, they found nothing.

Armstrong feels lucky to have low blood pressure and continues to eat healthy and exercise daily. "Fainting has caused me some problems, but the ER doctor gave me good advice," says Armstrong. "He said to lie down if I ever feel faint--not put my head between my legs."

Dr. Ellison explains that if you have recurrent fainting or other troublesome symptoms, you should be evaluated. Common symptoms of low blood pressure that can be treated (once the cause is known) include:

  • Dizziness or lightheadedness
  • Fainting
  • Fatigue
  • Blurred vision
  • Nausea

"In most cases, low blood pressure is benign and you don't need to worry--just address the symptoms," says Dr. Ellison. "You generally don't have to seek treatment unless you have bothersome symptoms, and then we can rule out anything more serious, which is rare."

According to the American Heart Association, low blood pressure can result from the following:

  • A decrease in blood volume
  • Heart problems
  • Endocrine problems
  • Severe infection (septic shock)
  • Anaphylactic shock
  • A miscommunication between the heart and the brain (primarily affects young people)
  • Nutritional deficiencies

It can also be caused by prolonged bed rest, pregnancy and certain medications. And if your low blood pressure is a result of high blood pressure medication, it's important to work with your doctor to find the best solution. "You want to find a regimen that effectively reduces your blood pressure, but also keeps you feeling as well as possible," says Dr. Ellison.

The dangers of high blood pressure

Now, the bad news. According to the Centers for Disease Control and Prevention (CDC), more than 50 million Americans have high blood pressure (hypertension), a condition that increases the risk for heart disease, stroke and other serious health conditions. But it's treatable.

Even if you're at risk for high blood pressure, or have it, there are steps you can take at any age to maintain normal blood pressure levels and prevent or reduce your health risks.

Preventing or controlling hypertension

"Medication is arguably the most effective thing we've done in decades to prolong life and reduce stroke and heart problems," says Dr. Ellison. "It's important to take your medication as directed and follow the lifestyle tips above to best manage your high blood pressure."

About 20 years ago, Boston resident Melanie Greenberg*, now 63, was diagnosed with high blood pressure at her annual exam. Although Greenberg had always maintained a healthy weight, exercised regularly and eaten a healthy diet, she had a genetic risk for the condition.

"My father and my aunt had high blood pressure," says Greenberg, "so I wasn't surprised when I was diagnosed." Her doctor prescribed blood pressure medication, and Greenberg took a course on meditation and relaxation.

Over the last 20 years, Greenberg's blood pressure continued to climb and she's had to increase her medication dosage to control it. "I take my medication as directed, try to use relaxation techniques and see the doctor several times a year to have my blood pressure checked," says Greenberg. "Fortunately, with some medication adjustments I have been able to keep it in the normal range." In addition, she maintains her healthy lifestyle as another way to decrease her health risks.

"Reducing blood pressure has a major impact on your longevity," says Dr. Ellison. It reduces your risk of:

  • Heart attack and stroke
  • Heart failure
  • Kidney failure
  • Aneurysm in any blood vessel
  • Losing the ability to think and remember

The Centers for Diseases Control and Prevention (CDC) and other health experts offer these lifestyle tips for preventing high blood pressure:

  • Eat a healthy diet with lots of fresh fruits and vegetables and not much salt
  • Maintain a healthy weight
  • Be moderately physically active on most days of the week
  • Don't smoke
  • If you drink alcohol, do so in moderation

Dr. Ellison suggests reducing your food consumption by one-third, which decreases calories and automatically reduces your salt intake. One way to do that is to add more fiber to your diet.

"To control high blood pressure, medication is arguably the most effective thing we've done in decades to prolong life and reduce stroke and heart problems," says Dr. Ellison. "It's important to take your medication as directed and follow the lifestyle tips above to best manage your high blood pressure."

Blood pressure: what's your number?

  • Normal results: In adults, the ideal top number (systolic pressure) should be less than 120 mmHg. The bottom number (diastolic pressure) should be less than 80 mmHg.
  • Prehypertension: Top number is consistently 120 to 139 or the bottom number reads 80 to 89.
  • Stage 1, Mild high blood pressure: Top number is consistently 140 to 159 or the bottom number reads 90 to 99.
  • Stage 2, Moderate to severe high blood pressure: Top number is consistently 160 or over or the bottom number is 100 or over.
  • Low blood pressure (hypotension): Top number reads lower than 90 or pressure is 25 mmHg lower than usual

Barbara Schuetze

Barbara Schuetze is a Portland, Ore., freelance writer who specializes in health and wellness topics. She has written for most of the major health systems in Oregon and Southwest Washington, and her work has appeared in magazines, newspapers and on the Web. She has been writing professionally since 1983.