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Do I have High Blood Pressure...and Should I be more Worried about my Top or my Bottom Number?

By: Thomas A. Rocco, Jr., MD

It is estimated that over 70 million people in the U.S. have high blood pressure (hypertension). However, only about 60% are aware of their hypertension and are receiving treatment for it. Almost 40% of Americans (28 million people in this country alone) with hypertension don't even know they have the problem. In addition, as our population ages and our waistlines increase, the number of Americans with hypertension continues to grow.

Why Does Blood Pressure Matter?

People commonly ask, "so what? I don't feel bad with my high blood pressure, so what's the point of worrying about it, or taking daily medications for it?" Hypertension is often referred to as the "silent killer", because it does not give you warning symptoms as it damages vital organs. Over time, your brain, your heart and your kidneys can all be severely affected by hypertension; resulting in an increased incidence of stroke, heart failure, heart attacks and kidney disease/dialysis. Furthermore, many studies have shown that effective treatment of high blood pressure will significantly reduce your chances of having a stroke, heart attack, heart failure or kidney failure. Treatment will increase your lifespan and improve your quality of life. This is true whether your 18 or 80.

Blood Pressure Measurement, Targets

So, how do you go about finding out if you have hypertension? As noted above, high blood pressure usually has no presenting symptoms. In fact, many people have high blood pressure for years without knowing it. So, you should have your blood pressure (BP) measured periodically, and make sure to write down the numbers. Record those readings and keep track of them over time. "Know your numbers", and share these numbers with your health care providers.

The systolic BP number is always recorded first, followed by the diastolic number. For example, a BP recorded at 130/70 mmHg (millimeters of mercury) is a systolic BP of 130 and a diastolic BP of 70. If the systolic BP (top #) is at or over 140 mmHg or the diastolic BP (bottom #) is at or over 90 mmHg on several occasions, then you do have hypertension. Your hypertension should be treated by a qualified medical professional.

If you have diabetes or chronic kidney disease, then your BP should be even lower. A systolic BP at or above 130 mmHg or a diastolic BP at or above 80 mmHg requires additional treatment if you have those chronic conditions.

If your systolic BP is between 120-139 mmHg, or your diastolic BP is between 80-89 mmHg, then you are considered to have pre-hypertension. You are at increased risk of developing hypertension and should discuss preventive options with your medical professional.

Which Number Is The Important One?

I'm frequently asked: "What BP number is more important, the top (systolic) or the bottom (diastolic) number?" Until the last decade or so, the common answer would have been the bottom number. However, several recent medical studies have shown that particularly as we age, the top (systolic) number is the more important one for assessing risk. The systolic blood pressure represents the pressure generated against the walls of your arteries, as your heart is forcefully contracting to pump blood throughout your body. The diastolic blood pressure is the pressure generated while the heart relaxes between contractions.

Recent studies indicate that systolic BP is the critical factor in determining risk of heart disease, stroke and kidney failure. Also, studies have shown that relaxing the BP targets for older individuals is no longer appropriate. For example, the old adage that your systolic BP should be "equal to your age plus 100" is simply not true and is misleading for diagnosis and treatment.

Isolated systolic hypertension (with the diastolic BP being normal) is the most common form of hypertension; and is present in more than two-thirds of adults over the age of 60 with high blood pressure. It is now clear that effective treatment of high systolic BP (systolic hypertension) results in reduced rates of heart failure, stroke, heart attack, kidney failure and death. This is true even in older patients.

Additional Questions

If you are diagnosed with high blood pressure, several questions often come to mind. "Will I need to take medication for the rest of my life?" "Will there be side-effects from my medication?" "Will lifestyle changes help to reduce my BP?"

A common misconception is that "once my BP is controlled, then I can stop my medication." Unfortunately, high BP is rarely cured, but rather needs life-long treatment. So, when your medication starts to run out, make sure you get the appropriate refills. And if you experience side effects from the medication, don't just stop it without notifying your health care provider. There are many different types of medications that effectively treat high BP. If one medication does not work well, or is causing you side effects, don't get discouraged; as your health care provider can find another medication that will work for you.

In terms of lifestyle changes, a diet that is lower in sodium chloride (salt) is often beneficial in reducing your BP. One diet that has proven benefits in reducing high BP, and improving outcomes in those with hypertension, is the DASH diet (Dietary Approaches to Stop Hypertension). The DASH diet is low in sodium and high in fruits and vegetables; and is a healthy alternative for the public in general . Examples of this diet can be obtained from your health care provider or on the Internet.

Regular aerobic exercise can also be very beneficial. Simple aerobic exercise such as walking should be performed for 30 minutes on several (most) days of the week. The DASH diet and regular exercise will also help you to lose weight if needed and to maintain your ideal body weight. All of these lifestyle changes have proven to be effective in reducing your BP, reducing your risk of heart disease and stroke, and improving your quality of life.

You now have a basic understanding of high BP and hypertension. In future articles, I'll provide additional information regarding the importance of good blood pressure control, the various medications used to treat hypertension, and the role of diet, exercise and other lifestyle modifications in the control of hypertension (for example check out our article on nutrition at To learn more about this, you can also access several good websites, using the links below:

  1. MedlinePlus High Blood Pressure
  2. American Heart Association: High Blood Pressure Website
  3. NHLBI: Your Guide to Lowering High Blood Pressure
  4. Hidden Salt (HHS HealthBeat March 31, 2011)


About the Author 

Thomas A. Rocco, Jr., MD Thomas A. Rocco, Jr., MD

Thomas A. Rocco, Jr., MD, F.A.C.C., F.A.H.A. is a Clinical Associate Professor of Medicine at the University of Rochester Medical Center and a Consultant in Cardiology and Cardiovascular Research at the Veterans Administration. He formerly directed the departments of Cardiology at Highland Hospital and Unity Hospital. His clinical and research interests include Preventive Cardiology, Hypertension, Congestive Heart Failure, and Geriatric Cardiology. He is the Principle Investigator on several clinical research projects, has lectured and published extensively, and has served on numerous community boards and agencies.

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The Rochester Healthnote Library consists of locally-authored articles either commissioned by Rochester Health or republished with the author's permission. The information provided in the Rochester Healthnote Library is for general informational purposes only and is not meant to be a substitute for professional medical advice and treatment. You should always seek the advice of your physician or other medical professional if you have questions or concerns about a medical condition.

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