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Dervilla M. McCann, M.D., F.A.C.C., is a Cardiology Consultant at Androscoggin Cardiology Associates in Auburn, Maine. Dr. McCann is a graduate of Tufts University School of Medicine. She completed her Residency at NYU/Bellevue Hospital in New York City. She received an Armed Forces Scholarship and served with the U.S. Navy for nine years. During this time, she completed her training in Cardiology and rose to the rank of Commander. She has served as the ICU Director at Camp Pendleton Naval Hospital at Camp Pendleton, California and the CCU Director at Bethesda Naval Hospital, Bethesda MD. Dr. McCann has published articles in the area of women's health and cardiac disease and is a frequent lecturer on these topics.

The History of Hypertension: Not a Modern Day Phenomenon

Based on the dissection of ancient Egyptian mummies, high blood pressure (hypertension) has been a health problem since the early Egyptian empires. The blood pressure cuff was invented in 1896, but it wasn't until the 1950s that we became aware of the importance of high blood pressure as a herald of the complications commonly attributed to "old age". Recent research has shown a critical relationship between high blood pressure and strokes, heart attacks, congestive heart failure, and vascular disease, which together comprise the leading cause of death in the United States for men and women.

What is Normal Blood Pressure?

The human heart pumps blood through the blood vessels in a wave-like pattern. The highest point of the wave corresponds to the heart's contraction. The blood pressure at the peak of the heart's contraction is known as the systolic blood pressure. When the heart relaxes, the blood pressure falls, and a lower level of blood pressure occurs, known as the diastolic blood pressure. This systolic and diastolic blood pressure is measured at routine doctor's visits and hospitalizations. If you are told that your blood pressure is 120 over 80, then your systolic pressure is 120 and your diastolic pressure is 80. This is an ideal blood pressure. Hypertension is defined as an elevation in the blood pressure over these ideal levels. The upper limit of normal is now defined as 135(systolic pressure) over 85(diastolic). If either the systolic or the diastolic blood pressure is persistently greater than this, hypertension is said to be present.

What Makes Blood Pressure Go Up? What Happens When it Does?

Blood pressure changes in each of us throughout our lives, and on a minute-to-minute basis. It tends to get higher as we age, and is usually lowest when we sleep. As we go through a normal day, it fluctuates and becomes elevated in response to stress, pain, hormonal levels, meals, and exercise. These are normal responses to our environment. In the disease of hypertension, the blood pressure becomes higher than necessary to maintain normal body functions. This elevation begins to damage the circulatory system, increasing the "wear and tear" everywhere there are blood vessels. The heart, which must work harder to push the blood through a higher-pressure environment, begins to increase in size. The walls of the heart thicken and the heart muscle doesn't relax normally. The walls of the blood vessels also thicken and become stiffer. They can develop damage to the inner lining of the blood vessel, with resulting cholesterol deposits at the places of damage. This process, known as atherosclerosis, can lead to strokes, heart attacks and blood vessel enlargements known as aneurysms.

What is White Coat Hypertension?

Most of us become a little anxious when we visit our doctors, and "white coat hypertension" is the term for the higher than usual blood pressure often recorded during a routine check. What we now know, however, is that if a doctor's visit begets high blood pressure, so does being late for an appointment, getting stuck in traffic, and getting a phone call from your car mechanic. It now appears that what used to be dismissed as a temporary increase in the blood pressure probably represents a true tendency to hypertension, which should be taken seriously and treated.

Why Does Hypertension Occur?

Although certain hormonal abnormalities cause hypertension, the vast majority of cases are secondary to genetic factors, obesity, age and inactivity. Smoking, diabetes and excess alcohol consumption make hypertension worse.  Salt intake does not play as great a role in the control or cause of high blood pressure as was once commonly believed.

Is Hypertension a Big Problem?

About fifty million Americans have high blood pressure. Almost half are not on treatment, and less than one third are adequately treated.  Costs of treatment of strokes, heart attacks and congestive heart failure cost billions of dollars yearly.

What Can I Do to Prevent Hypertension?

Talk with your physician. A healthy diet and adequate exercise will help. If you smoke, quit. If your doctor prescribes medications, take them as directed. If you take herbal or nutritional supplements, be aware that some can cause hypertension while others may interfere with your medication.

Additional resources

Clinical Hypertension 7th edition, Norman Kaplan M.D., Williams and Wilkins 1998

A Review of the sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood pressure, Schwartz GL, Current Opinion in Cardiology 1999 March; pages 161-168

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Created: 1/17/2001  -  Dervilla M. McCann, M.D., F.A.C.C.

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