High Blood Pressure

What Is High Blood Pressure?

Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps blood. High blood pressure (also called hypertension) is a serious condition that when blood pressure rises and stays high over time. It can damage the heart, blood vessels, kidneys, and other parts of your body. About 1 in 3 adults in the United States has high blood pressure. If left uncontrolled, high blood pressure can lead to coronary heart disease, congestive heart failure, stroke, kidney failure, vision loss, erectile dysfunction, and other health problems.  People of all ages and backgrounds can develop high blood pressure.  Importantly, high blood pressure is preventable.

How Is High Blood Pressure Diagnosed?

Blood pressure is measured as systolic and diastolic pressures, and is written with the systolic number above or before the diastolic number, such as 110/70 mmHg. Systolic pressure refers to the force when the heart muscle rejects blood from the heart to the body. Diastolic pressure refers to the force when the heart is at rest between beats.  While it changes with physical activities and stress, blood pressure should normally be less than 120 mmHg systolic and less than 80 mmHg diastolic for adults. Table 1 shows blood pressure categories defined by the American Heart Association.  

Table 1  Blood Pressure Categories in Adults

What Are the Symptoms of High Blood Pressure?

Except in most extreme cases known as hypertensive crisis (with systolic higher than 180 mmHg or diastolic higher than 110 mmHg), high blood pressure is often a disease without symptoms. Because of the symptomless nature of high blood pressure, many patients may not be aware that high blood pressure is damaging the arteries, heart, and other organs. High blood pressure is sometimes called "the silent killer".

What Are the Risk Factors for High Blood Pressure?

Scientists have identified several factors that can increase the probability of developing high blood pressure.  The major risk factors include:

• Family history of high blood pressure: High blood pressure can run in families. People can inherit genes that make them more likely to develop high blood pressure. If your parents or close blood relatives have had high blood pressure, you are more likely to develop it, too.
• Advanced age: Blood pressure tends to rise as you get older. It is astonishing that more than 2/3 of the people aged 75 years and older have high blood pressure (Table 2).

Table 2 High Blood Pressure Prevalence in Different Age Groups

Age (years)	Men (%)	Women (%)
20-34	9.2	2.2
35-44	21.1	12.6
45-54	36.2	36.2
55-64	50.2	54.4
65-74	64.1	70.8
75 and older	65.0	80.2

• Poor diet: A diet that is high in fat and sugar, and low in essential nutrients contributes to health problems like high blood pressure.
• Too much sodium: Sodium is an element in salt. Too much sodium can increase blood pressure.  Salt also keeps excess fluid in the body, and add to the burden on the heart.
• Lack of physical activity: People who are not physically active are more likely to develop health problems like high blood pressure. Inactivity also makes it easier to become overweight, which is another risk factor for high blood pressure.
• Overweight and obesity: High blood pressure is twice as common in adults who are obese (Body Weight Index ≥ 30) than in those who have normal weight.  
• Drinking too much alcohol: Small amount of alcohol can potentially lower blood pressure by 2 to 4 mmHg. But too much alcohol, generally more than one or two drinks a day for women and men respectively, can actually raise blood pressure by several points.  Too much alcohol can also contribute to obesity, heart failure, and irregular heart beat.
• Certain pre-existing diseases (e.g. kidney problem and aorta abnormality): In some cases, high blood pressure is caused by a pre-existing problem. Once the root cause is corrected, blood pressure typically returns to normal.

You cannot change heredity, but you can take simple steps to lower your other risk factors and improve your lifestyle. Lifestyle choices have allowed many people with a strong high blood pressure family history to avoid developing high blood pressure.

Prevention and Treatment of High Blood Pressure

In addition to medications, you can improve life style and prevent/delay the development of high blood pressure.  National Institutes of Health and the American Heart Association recommend the following approaches:

• Eat a better diet:  Consider the Dietary Approaches to Stop Hypertension (DASH) for an overall eating plan. Studies indicate that elevated blood pressures can be reduced by eating DASH diet plan that emphasizes fruits, vegetables, and low fat dairy foods and is low in saturated fat, total fat, and cholesterol. The DASH eating plan includes whole grains, poultry, fish, and nuts and has reduced amounts of fats, red meats, sweets, and sugared beverages.
• Reduce sodium intake:  A key to healthy eating is choosing foods lower in sodium. The current recommendation is to consume less than 2.4 grams (2,400 milligrams) of sodium a day. That equals 6 grams (about 1 teaspoon) of table salt a day. The 6 grams include all salt consumed, including that contained in the food and that used in cooking and at the table. Recent research has shown that diets with less than 1,500 mg of sodium is more effective in lowering blood pressure.
• Get enough potassium.  Potassium blunts the effects of sodium.  A diet that includes natural sources of potassium is important in controlling high blood pressure. The recommended daily intake of potassium for an average adult is about 4,700 milligrams per day. However, caution need to be exercised since too much potassium can be harmful in many older persons and those with concurrent kidney disorders.
• Be physically active: Even moderate physical activity is beneficial for your health. Warming up before exercise ensures the heart speed up gradually. You also decrease the risk of injury or soreness. Cool-down prevents your blood pressure from dropping sharply, which can be dangerous. Talk to your doctor if your medical conditions limit your ability to do some regular physical activity, and they may recommend other activities for you.
• Maintain a healthy weight: Overweight puts you at greater risk of developing high blood pressure. Even a small weight loss can reduce blood pressure and/or prevent hypertension in many overweight people (those with a Body Mass Index of 25 or greater).
• Limit alcohol consumption: Over the past several decades, some studies have suggested that drinking alcohol, especially red wine, is associated with reduced mortality due to heart disease in some populations. The components in red wine, such as flavonoids and other antioxidants, may reduce heart disease risk. However, no large scale trials have been conducted to determine the specific effect of wine or alcohol on the risk of developing heart disease or stroke. Since drinking too much alcohol can raise your blood pressure, the American Heart Association currently recommends limiting alcohol consumption to no more than two drinks per day for men and no more than one drink per day for women.

• There are about 31% adults in the United States (i.e. 76 million people) have high blood pressure. In addition, 30% American adults (i.e. another 74 million people) have prehypertension.
• High blood pressure is a major risk factor for heart disease, stroke, congestive heart failure, and kidney disease, among many other diseases.
• High blood pressure was listed as a primary or contributing cause of death for 347,689 Americans in 2008.
• In 2010, high blood pressure cost the United States $76.6 billion in health care services, medications, and missed days of work.
• Advanced age is a major risk factor for development of high blood pressure (Table 2). 
• High blood pressure is found in all ethnic groups (Table 3), and the rates are increasing in both blacks and whites. Rate of high blood pressure in blacks in the United Stated is among the highest in the world. 

Table 3 Comparison of High Blood Pressure Prevalence in Different Ethnic Groups

Ethnic Group	Men (%)	Women (%)
African Americans	42.2	44.1
Mexican Americans	24.8	28.6
Whites	31.2	28.3
All	31.8	30.3