High blood pressure, or hypertension, is simply the condition of having the pressure in the arterial system higher than normal. While there are rare cases of a specific disease which causes high blood pressure, the vast majority of cases have no known cause and are labeled as essential hypertension.
Blood pressure was not widely measured until World War I when a Russian surgeon, Korotkov reported his method of using a cuff about the arm to measure the blood pressure. However, physicians did not believe that this was important and often attributed high blood pressure to a normal aging process. The life insurance companies, however, determined that high blood pressure shortened life span.
In the 1920’s the physicians at the Mayo Clinic described malignant hypertension. It was described as malignant because 79% of the patients were dead within one year. These patients had very high blood pressure, a change in the eye known as papilledema (swelling in the back of the eye). Most patients also had changes in the heart or kidney because of the high blood pressure.
While there was no effective treatment before World War II, when studies on the natural history of hypertension led to the following conclusions:
- Hypertensive men die earlier than hypertensive women
- The earlier hypertension develops, the worse the disease
- “Labile” hypertension has a better outcome than “fixed” hypertension
- Generally speaking, the higher the blood pressure, the shorter the life span
- Hypertension with target organ damage (damage to the heart or kidneys) is worse than hypertension alone.
Effective treatment was not developed until the 1950’s, and it was 1967 before the first Veterans Administration report appeared which documented that treatment of hypertension markedly lessened the rate of stroke, accelerated hypertension, and heart failure.
In the 1970’s the National High Blood Pressure Education Program was initiated by the National Institute of Health. Recently they issued the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7). The key messages of this report are:
- Beginning at 115/75, cardiovascular risk doubles for each increment of 20/10.
- Individuals with a blood pressure between 120/80 and 139/89 require lifestyle modifications to prevent the progressive rise in blood pressure and cardiovascular disease.
- For those older than 50 years old, the systolic blood pressure is a more important risk factor than diastolic blood pressure.
- Many individuals will require multiple medications to control their blood pressure.
- Regardless of therapy or care, hypertension will be controlled only if patients are motivated to stay on their treatment plan.
Even with the extensive public education that has occurred with hypertension only about half of those with hypertension are aware of their condition and only about half of those who are aware that they have hypertension are treated.
Blood pressure rises with age in all developed cultures. In the United States about 25% of the population has high blood pressure by the age of 50. By the age of 70 it is about 40%.
What is normal?
- A blood pressure of less than 120/80 is considered normal.
- Above 120/80 but less than 140/90 is not normal and is defined as Prehypertension.
- Stage I hypertension is defined as a pressure between 140/90 and 160/100
- Stage II hypertension is a pressure above 160/100.
The only way to know one’s blood pressure is to measure it. A physician can accurately do this in his office and this should be performed annually.
If you do have high blood pressure, there are several lifestyle activities that do help. The most important is to avoid tobacco. Next eat well and exercise. A normal body weight and an active lifestyle are important. Avoiding oils and fats, restricting salt and high caloric foods, and exercising make a big difference. Do eat fresh fruit and vegetables and lean cuts of meat. Walking, swimming, cycling, or other forms of aerobic exercise not only help to control your weight and blood pressure, but also makes you feel better.
Finally do take the medication that your physician prescribes. This is so important. Keeping blood pressure well controlled will result in a marked reduction in the risk of strokes, heart failure, kidney failure, and heart attacks.
Authored by: Richard B. Johnson, PhD., M.D., F.A.C.P.