High blood pressure, also known as hypertension, is the most common cardiovascular disease. In the United States, 80 million people over age 6 have hypertension (1 in 4 Americans or 1 in 3 adults). One-third of people with hypertension are unaware that they have it. Hypertension is the leading cause of stroke and a major cause of heart attack.

Blood pressure
The heart pumps blood into the arteries (blood vessels), which circulate it throughout the body. Blood pressure is the force of blood pushing against blood vessel walls as it flows through. The blood pressure is recorded as two numbers. The higher number (systolic) measures the pressure in the arteries when the heart beats and fills them with blood while the second number (diastolic) measures the pressure when the heart rests between beats.

Blood pressure readings can be categorized as:
Normal: Less than 120/80
Prehypertension: 120-139/80-89
Stage 1 hypertension: 140-159/90-99
Stage 2 hypertension: above 160/100

Causes
In the United States, the cause of hypertension cannot be determined in 95% of cases and this is called essential hypertension. Certain risk factors have been identified including age, race, smoking, diabetes, obesity, sedentary lifestyle, excessively salty diets, excessive alcohol consumption (1 to 2 drinks daily), stress, and insufficient intake of potassium, calcium, and magnesium. Hypertension is usually familial and affects men more than women. Five percent of cases of hypertension have an underlying cause and is called secondary hypertension. Causes include kidney diseases, adrenal/ thyroid disorders, pregnancy, birth control pills and common cold medicines.

Symptoms
There are usually no symptoms or signs of hypertension (silent killer). The only way to know if you have hypertension is to check your blood pressure. If your blood pressure is extremely high, you may be having a hypertensive crisis and may develop symptoms including severe headache, fatigue or confusion, vision problems, chest pain, difficulty breathing, irregular heartbeat and blood in the urine. You must see a healthcare provider immediately as this could result in a heart attack or stroke.

Diagnosis
Blood pressure readings of 140/90 or higher, taken on at least 2 occasions confirms you have high blood pressure and requires treatment if it remains high. People with blood pressure readings of 200/120 or higher need treatment immediately.

Complications
Hypertension damages the major organs in the body and may result in a stroke, heart attack, congestive heart failure, kidney failure, vision problems or even death. Treatment Hypertension is treated with lifestyle modification and medications. Lifestyle changes include losing weight (maintaining a healthy weight), stopping smoking, eating a healthy diet with less salt and exercising regularly. Several medications are available for treatment, so ask your doctor about alternatives if you develop intolerable drug side-effects. Diabetics are treated at blood pressures above 135/80 because of increased risk of complications. Home blood pressure monitoring is recommended. Follow-up care is important. See your healthcare provider periodically as medications may need to be reviewed over time.

Prevention
Check your blood pressure at least once a year to ensure you don't have hypertension. You can help lower your chance of developing hypertension by making lifestyle changes. Consult your healthcare provider before starting an exercise program if you are inactive or over the age of 40 or have chronic health problems.

WebMD Medical Reference from MedicineNet