Why Your Blood Pressure Matters

By Merle Myerson, MD, EdD, FACC Director, St. Luke’s and Roosevelt Hospitals Cardiovascular Disease Prevention Program Pre-Exercise Heart Screening Program Assistant Professor of Clinical Medicine and Epidemiology Columbia College of Physicians and Surgeons

By Merle Myerson, MD, EdD, FACC

High blood pressure, also known as hypertension, is often called the Silent Killer because many people are not aware that their blood pressure is too high. One out of 3 adults in the US suffers from hypertension. 

Many people with high blood pressure may not feel any symptoms and therefore not have their hypertension diagnosed – and treated – for many years. Hypertension is the leading cause of stroke and can cause severe damage to other organs – eyes, kidneys and the arteries that bring blood to the heart muscle (coronary arteries). That’s why your blood pressure number is just one of the lifesaving numbers you need to know.

What Is a Normal Blood Pressure?

Normal, or ideal, blood pressure is less than 120/80 mm Hg. 

Blood pressures of 120/80 – 140/90 are considered “prehypertension.” Blood pressures in this range do not necessarily require medication and many people in this category can bring their blood pressure down with lifestyle modification, such as losing weight and reducing salt intake.   People with cardiovascular risk factors, diabetes or kidney disease with blood pressure in this range often receive medications. 

If a person’s blood pressure is over 140/90 they are considered to have hypertension. A trial of lifestyle modifications can be considered although many patients will require medication along with lifestyle modification.  

What Do the Numbers Mean?

There are two numbers in the blood pressure measurement. The first, or top number, is called the systolic blood pressure and represents the pressure in your arteries (the blood vessels that carry blood with oxygen from the heart to all parts of the body) when the heart contracts (beats) and pumps blood out of the heart and into the arteries.  

The second, or bottom, number is called the diastolic blood pressure and represents the pressure in your arteries while your heart relaxes between beats.  

Both numbers are important and elevation in one, or both, are considered when making the diagnosis of hypertension.

How Is Blood Pressure Measured?

Blood pressure is measured with a sphygmomanometer, more commonly called a blood pressure cuff.  The cuff is placed around the upper arm just above the elbow and inflated, then deflated while listening with a stethoscope over the artery in the arm. Home blood pressure machines may use a cuff attached to a machine but without the need of a stethoscope.  

Blood pressure should be measured after a person has sat quietly for at least 5 minutes and not had caffeine, tobacco or exercised for at least 30 minutes.  A proper size cuff should be used.  Blood pressure can be taken on either arm and is often taken on both arms for comparison.  The pressure in the dominant arm may be slightly higher. The difference between the two arms  is generally 10 mm Hg or less.

The diagnosis of hypertension should be confirmed with measurements made on several days, although if severely elevated, treatment may be initiated after one reading. It is often helpful to have a special monitor that a person takes home and records blood pressure for 24 hours.

Monitoring Your Blood Pressure at Home

Research shows home blood pressure monitoring can be vital to reducing a patient’s risk of stroke, heart attack, heart failure or kidney failure. In fact, internationally recognized organizations, such as The American Heart Association, recommend any patient with or at risk of hypertension should purchase a clinically validated home blood pressure monitor and regularly monitor their blood pressure at home. 

More than 50% of people with high blood pressure who monitor at home show an improvement in medication compliance and are quicker to take action.

What Causes High Blood Pressure?


Many factors can contribute to developing high blood pressure. Some can be controlled, such as weight, eating too much salt, drinking too much alcohol, and lack of physical exercise. The exact role of stress is unclear but is felt to be a factor as well.

Those factors that cannot be controlled are heredity (the genetic predisposition to having high blood pressure), older age and race. In this country, African-Americans are at higher risk for hypertension. There are secondary causes of hypertension such as endocrine problems that are much less common but are often considered in a young person or a person with very hard to control blood pressure. 

How Is Hypertension Treated?

Lifestyle Modification

Changes in a person’s lifestyle can significantly lower blood pressure. Some people can lower pressure enough to where they do not need medications while with others the changes can reduce the amount of medications needed.  


For many, but not all people, reduction in sodium intake is very important. The American Heart Association’s 2010 guidelines state that Americans should reduce sodium intake to less than 1500 mg daily. It is often hard for people to add up milligrams but realizing what foods are high in sodium, reading food labels, and not using the salt shaker can help. As a reference point, one-quarter teaspoon of salt has 600 mg. A large study from the National Institutes of Health showed that a special diet, Dietary Approaches to Stop Hypertension, or DASH diet, could help lower blood pressure. This diet emphasizes fruit, vegetables, low- and non-fat dairy products, lean meats, fish, beans and nuts. 


Physical activity can be helpful in many ways.  Expending more energy results in weight loss but exercise is felt to lower blood pressure directly as well.

Weight Loss

Maintaining a healthy weight for one’s height will also reduce blood pressure


All people with hypertension should be treated with lifestyle modification; however, many will still need medication. There are several types or classes of blood pressure medications that work in different ways. Some examples are diuretics (water pills), and vasodilators that relax the arterial wall. It is common to use one or more medications from different classes. 

Medications are also chosen according to other medical conditions that a patient may have. For example, a beta blocker may be used in a person with high blood pressure who has also had a heart attack. A person may be on one, two, three or more different medications. It is important to take medications as prescribed as they are formulated to work for either 12 or 24 hours. Some people experience side effects from the medications, and it is important to work closely with health care providers to establish a regimen that is effective and also well tolerated. There are many generic medications available and most are considered to be equivalent to brand-name formulations.  

Article written by Merle Myerson, MD, EdD, FACC
Director, St. Luke’s and Roosevelt Hospitals Cardiovascular Disease Prevention Program Pre-Exercise Heart Screening Program...