Hypertension is characterized by a persistent increase in the force that the blood exerts upon the walls of the arteries. It is normal for this force to increase with stress or physical exertion, but with hypertension, the patient’s blood pressure is high even at rest.
Blood pressure is measured with two numbers: systolic (the top number in a reading) and diastolic (the bottom number). It is measured in millimeters of mercury (abbreviated mm Hg) using a device called a sphygmomanometer. Systolic pressure refers to the force of blood against the walls of the arteries when the heart contracts to pump blood to the rest of the body. Diastolic pressure refers to the pressure within the arteries as the heart relaxes and refills with blood (which explains why the diastolic number is always lower than the systolic measurement).
Hypertension is defined as systolic pressure greater than 140 mm Hg or diastolic pressure greater than 90 mm Hg; optimal blood pressure is less than 120/80 mm Hg.
Some 60 million Americans have hypertension, but only about half of them know it, primarily because it so rarely causes any noticeable symptoms and is usually detected only incidentally during a routine physical examination. But left untreated, hypertension promotes atherosclerosis (narrowing of the arteries) and increases the risk of heart attack, stroke, kidney damage and destruction of tiny blood vessels in the eye, which can result in vision loss. For these reasons hypertension is often called “the silent killer.”
Fortunately, if detected early and treated properly, the prognosis is good.
- Notify your doctor if you experience any unpleasant side effects from antihypertensive medications. Adjustments in your prescription may eliminate the problem; never elect to stop taking your medication without consulting your doctor.
- Get prompt medical attention if you experience symptoms such as ringing in the ears, dizziness, recurrent headaches or nosebleeds—these may be signs of dangerously high blood pressure.
- All adults should have their blood pressure checked at least once a year. This practice is especially applicable if you are male, over age 40, overweight (particularly if you have been overweight since youth), sedentary, or if you have a family history of hypertension or heart disease.
- Dizziness or ringing in the ears.
- Numbness or tingling in the hands or feet.
- Drowsiness or confusion.
- A family history of hypertension.
- Gender (women are at one-half to two-thirds the risk of men).
- Race (incidence is up to twice as great among African Americans as among Caucasians).
- Emotional stress.
- Sedentary lifestyle.
- Obesity, excessive alcohol consumption, cigarette smoking and a high-sodium diet.
When an underlying cause can be identified, the condition is known as secondary hypertension. Such causes include kidney disorders, adrenal tumors and pregnancy.
- Keep weight within a healthy, normal range.
- Avoid cigarettes and restrict alcohol intake to no more than two drinks a day.
- Aim to get at least 20 minutes of vigorous aerobic exercise (like jogging, biking, dancing or swimming) a day, three or four days a week.
- Limit intake of sodium to less than 2,500 mg a day.
Diagnosis requires accurate measurements of elevated blood pressure on at least three different occasions over a period of a week or more. Some people exhibit “white coat hypertension,” wherein blood pressure is consistently high in a clinical setting but is normal when measured at home. Other people sporadically alternate between normal and high readings (known as labile hypertension). Some patients may be asked to wear a portable monitor that automatically records their blood pressure periodically over the course of a day or so, or to measure their blood pressure periodically at home with an electronic monitor.
Your physician may also run blood and urine tests to look for kidney damage and an electrocardiogram (ECG) to check for heart damage (both possible complications of hypertension).
Hypertension, or high blood pressure, is one of several conditions managed by doctors with The Johns Hopkins Ciccarone Center for the Prevention of Heart Disease, directed by Dr. Roger Blumenthal. The center employs a multidisciplinary team of cardiologists, an endocrinologist and a nurse practitioner and specializes in managing adults who are at high risk for future cardiovascular disease either because of risk factors such as hypertension, diabetes, high cholesterol, cigarette smoking, or sedentary lifestyle or because of a known family history of heart disease or peripheral vascular disease.
Our personalized, comprehensive approach to lifestyle and medical management can slow the progression of cardiovascular disease and decrease one’s future risk of heart attack, stroke, bypass surgery or angioplasty. We also sponsor research that includes both clinical trials and basic molecular studies.
During your hypertension evaluation, a Johns Hopkins cardiologist will examine you at the Outpatient Center or satellite facility, Johns Hopkins Heart Health, in Timonium, Maryland. If necessary, you may undergo one or more of the following tests, which are performed at these outpatient locations
- The doctor will need to take blood pressure readings on at least three different occasions over a period of a week or more. Some patients may be asked to measure their blood pressure periodically at home with an electronic monitor or to wear a portable unit that takes such measurements.
- Blood and urine samples may be taken to rule out kidney damage, a possible complication of hypertension.
- An electrocardiogram, also called an ECG or EKG, records your heart’s electrical activity during rest to determine abnormal heart rhythms.
“Patients at Johns Hopkins get the benefit of a state-of-the-art comprehensive approach to lipid and vascular disease management. Our goal is to halt the progression of atherosclerosis and to minimize the risk of a future heart attack or stroke. We try to optimize lifestyle and medical management to achieve this goal.” -- Roger Blumenthal, M.D., F.A.C.C.
The Johns Hopkins Ciccarone Center for the Prevention of Heart Disease utilizes a personalized, comprehensive approach to lifestyle and medical management that can slow the progression of cardiovascular disease and decrease one’s future risk of heart attack, stroke, bypass surgery or angioplasty.
The first line of treatment for essential hypertension involves adopting healthy lifestyle measures. Mild hypertension may respond positively to these measures and thus require no further medical therapy. For example, some studies indicate that as many as 30 percent of those with high blood pressure (specifically, the type known as sodium-sensitive hypertension) can control it by lowering their salt intake. Our nurse health educators specialize in helping people to improve their lifestyle habits. We have an excellent cardiac rehabilitation program and clinical exercise program at Johns Hopkins Heart Health in Timonium.
If lifestyle changes prove inadequate, your doctor may prescribe one or more of the many available medications. Here are the “ABCs” of drugs for hypertension:
(A) Ace inhibitors or angiotensin receptor blockers prevent the formation of a hormone that constricts blood vessels.
(B) Beta blockers interfere with nerve receptors in the heart, causing the heart rate and blood pressure not to rise as quickly in response to exercise.
(C) Calcium channel blockers reduce the ability of arterial walls to constrict.
(D) Diuretics help increase the elimination of salt and water from the body.
There are also combination drugs to pair ace inhibitors with diuretics or angiotensin receptor blockers with diuretics. Your doctor will determine which course of treatment will most benefit your condition.
For secondary hypertension, the underlying disease must be identified and treated.