High blood pressure is a condition in which the pressure of the blood pumping through the arteries is abnormally high. This increases the risk of stroke, aneurysm, heart failure, heart attack and kidney damage. More than 50 million Americans have high blood pressure, and a third are entirely unaware of it.
A blood pressure reading consists of two numbers:
- Systolic pressure, which indicates the contraction of the heart muscle
- Diastolic pressure (the second number) measures the blood pressure when the heart relaxes between beats
A reading of 140/90 or higher qualifies as high blood pressure. An ideal blood pressure reading is 120/80. However, blood pressure varies throughout a lifetime. Children have much lower blood pressure than adults. As people grow older, their blood pressure rises. In general, readings are higher in the morning and lower while a person sleeps. Physical activity makes blood pressure go up, and rest causes it to go lower.
A high blood pressure reading of more than 180/110 should be considered an urgency and seen by a doctor as soon as possible. In rare cases, blood pressure of 210/120 or more is seen. This should be considered an emergency and treated immediately. It can cause a variety of severe symptoms and result in death in three to six months if not treated.
Hypertension is often called the "silent killer" because symptoms of high blood pressure do not appear for years until a vital organ is threatened. Signs of long-untreated high blood pressure (such as headache, fatigue, nausea, vomiting, shortness of breath, restlessness and blurred vision) can be the result of damage to the brain, eyes, heart and kidneys.
For most, the causes of high blood pressure are not known. Researchers believe several factors together may create higher pressure in the arteries. In some cases, diseases cause blood pressure to increase. These include:
- Arteriosclerosis, which makes arteries stiff and unable to widen in response to rising blood pressure
- Cushing's syndrome, which involves an overactive thyroid gland or a tumor in an adrenal gland
- Kidney diseases or injury
- A smoker
- African American. An estimated 32% of African Americans (compared with 23% of Caucasians and 23% of Mexican Americans) have high blood pressure.
- Older. About 75% of women and almost 66% of men aged 75 or older have high blood pressure. (Only about 25% of people between the ages of 20 and 74 have high blood pressure.)
- Overweight. High blood pressure occurs twice as often in people who are obese as it does in people who are not.
- Sedentary
- Under stress
High blood pressure is often discovered during a routine visit to the doctor or when another illness strikes. Your blood pressure is measured after you have been sitting or lying down for about five minutes. Your blood pressure may be measured again after you have been standing for a few minutes.
Because blood pressure readings can vary widely, it may take several readings or readings done on different days to confirm a diagnosis of high blood pressure. In cases where there is doubt, a 24-hour blood pressure monitor worn on the hip and connected to a blood pressure cuff on the arm can be used.
After determining that you have high blood pressure your doctor will look for possible causes of the high blood pressure and any effects it may have on key organs, such as your heart, kidneys, brain and blood vessels. Your doctor may recommend:
- An electrocardiogram
- Blood tests
- A urine test to check for signs of kidney damage
It may be necessary to examine your retina, the light-sensitive membrane inside the back of the eye. This is the only place where your doctor can directly see the effects of high blood pressure on your blood vessels
If an underlying disease or condition has been identified as the cause, treatment of high blood pressure will focus on that condition. When it has been brought under control, your high blood pressure may go away.
Before using drugs to control high blood pressure, most doctors will suggest:
- Avoiding alcoholic drinks
- Cutting down on salt
- Exercising regularly
- Losing weight
- Making sure you get enough calcium, magnesium and potassium
- Quitting smoking
- Diuretics to rid the body of excess salt and water
- Angiotensin-converting enzyme (ACE) inhibitors to dilate the arteries and relieve pressure
- Andrenergic blockers to help the body avoid high blood pressure caused by stress
- Calcium-channel blockers, which cause blood vessels to widen using a different mechanism
Because drugs to lower high blood pressure work in different ways and have different effects, it may be necessary to work with your doctor over a period of time trying different drugs or combination of drugs to best manage your high blood pressure with the least side effects.
