High blood pressure (HBP), or hypertension, is a disorder that may not cause symptoms. People affected by it often do not even know they have it. But HBP is a serious condition that can lead to stroke, heart disease, kidney failure, and other health problems. The good news is that adequate management of HBP reduces the likelihood of having a complication such as stroke.
As blood is pumped from the heart to the body via blood vessels, it creates pressure against the blood vessel walls. A normal blood pressure in critical to life. If the blood pressure is too low, the body will not receive an adequate supply of blood. This state is known as shock. If the blood pressure is too high, blood vessels and the organs they supply (aka target organs) may sustain damage. The brain and kidneys are examples of target organs.
A blood pressure reading is an indirect measure of this pressure. When that reading goes above a certain point, it is called high blood pressure. As many as 50 million Americans may have HBP. Among people age 65 and older, about 40 percent of whites and 50 percent of blacks have HBP. It should be noted that HBP is defined and that the definition changes as our knowledge of the cardiovascular system increases.
To test blood pressure, a doctor or nurse places a cuff around the patient’s arm above the elbow, pumps air into the cuff, and then reads the measurements as the air is let out. The test is painless and takes only a few minutes. The blood pressure cuff used needs to be sized for the individual. If the cuff is too large, the recorded pressure will be low. Conversely, if the cuff is too small, the blood pressure reading will be increased.
A person’s blood pressure measurement may need to be taken several times from a standing position as well as a sitting position. If someone’s blood pressure is high the first day, the doctor will want measurements from different days before deciding upon a diagnosis of HBP. These steps are necessary because blood pressure changes so quickly. Also, blood pressure can be affected by many factors, including the normal feelings of worry during a visit to the doctor.
Because HBP is so common, everyone should have his or her blood pressure tested once a year. Blood pressure readings are given in two numbers. Systolic blood pressure is the pressure within the vessel when the heart is contracting. Systolic BP is the first value in a measurement. The pressure is measured in millimeters of mercury. Diastolic pressure is the force within the vessel when the heart is relaxed. For people without medical conditions such as diabetes or chronic kidney disease, a blood pressure above 140/90 is defined as hypertension. The following table shows the current classification of blood pressure by the 7th Joint National Committee on prevention, detection, evaluation, and treatment of high blood pressure hypertension (JNC-7).
|BP classification ||Systolic BP ||Diastolic BP|
|normal ||Less than 120 ||Less than 80|
|prehypertension ||120 to 139 ||80 to 89|
|Stage 1 ||140 to 159 ||90 to 99 |
|Stage 2 ||Greater than or equal to 160 ||Greater to or equal than 100|
What type of evaluation should be done in patients with HBP?
The evaluation of a patient with hypertension includes several components:
• Identifying treatable causes of HBP
• Determining other risk factors for cardiovascular disease
• Identifying target organ damage
An evaluation consists of a medical history, focused physical exam, and certain laboratory tests.
What BP should one try to achieve when treating hypertension?
The JNC-7 recommends that most patients try to achieve a target blood pressure of less than 140/90. Patients with hypertension and diabetes or renal disease should aim for a target of less than 130/80, Patients who achieve these targets are less likely to experience complications of HBP.
What if just the first number Is high?
Often in older adults the first number (the “upper” or “systolic” number) is high while the second (the “lower” or “diastolic”) number is normal. This condition is called isolated systolic hypertension, and it also should be treated. Studies prove that lowering the systolic number cuts down on strokes and heart attacks in people age 60 and over. Hypertension is usually a chronic and progressive condition. Each sustained increase in blood pressure increases the risk of death and disease.
What causes HBP?
Some cases of HBP are caused by other illnesses. This kind of HBP is called secondary hypertension, and it is often resolves once the original medical problem is cured. Important causes of secondary hypertension include chronic kidney disease, renal artery stenosis, sleep apnea, certain drugs, and some diseases of the endocrine system. Most HBP, however, is primary (formerly called essential) hypertension. This kind cannot be cured but can be kept under control by regular, ongoing treatment.
Doctors think that many things combine to cause HBP. Risk factors include obesity, excessive alcohol consumption, and excessive sodium in the diet.
Everyone’s blood pressure rises during periods of stress or exercise. But avoiding stress will not prevent high blood pressure. You can have HBP even if you are usually a calm, relaxed person.