High Blood Pressure (Hypertension)
[article by Sam Joffe, M.D.]
High blood pressure is known as the "silent killer". You can have it for many years without experiencing any pain or symptoms, and yet, it can be a direct cause of heart attack, stroke, kidney disease, and even blindness. As we age, our arteries stiffen and may become lined with fatty deposits, increasing resistance to blood flow and raising blood pressure. Over half of Americans above the age of 60 have high blood pressure. Fortunately, high blood pressure can often be controlled with lifestyle changes and medication. Hypertension is a medical term that refers to blood pressure elevated beyond the normal, healthy range.
What is blood pressure?
Blood pressure refers to the force exerted by blood on the walls of arteries, much like the air pressure in a tire. Blood pressure is one of the 4 vital signs and is usually measured with an inflatable arm cuff, a familiar ritual when visiting the doctor. Two numbers are reported, for example, "120 over 80". The first number is the pressure when your heart is pumping (systolic pressure), while the second number is the pressure when your heart is filling (diastolic pressure).
How do I know if I have high blood pressure?
The table below shows ranges for normal and abnormal blood pressure:
| ||Systolic Pressure||Diastolic Pressure|
|Normal Blood Pressure||<120||<80|
|Hypertension, Stage 1||>140||>90|
|Hypertension, Stage 2||>160||>100|
Since blood pressure naturally varies throughout the day and under different circumstances, blood pressure should be measured several times before a diagnosis of hypertension is made. To accurately measure blood pressure, you should sit quietly for 5 minutes and measure blood pressure in both arms. Each increase in blood pressure of 20/10 doubles the risk of cardiovascular disease.
What causes high blood pressure?
While a small minority of cases may be caused by a hormonal imbalance, kidney abnormality, or other specific problem, the vast majority of cases of high blood pressure (over 90%) develop gradually over time and are not caused by any single identifiable cause. Risk factors for high blood pressure fall into 2 groups: Controllable and uncontrollable. Uncontrollable factors include age, race, gender, and heredity. Blood pressure increases with age, and also tends to be higher in African Americans, males, and individuals with a family history of high blood pressure. Controllable risk factors for high blood pressure include weight, salt intake, alcohol, lack of exercise, and stress.
How can I lower my blood pressure?
The best way to lower your blood pressure is through lifestyle changes, but medications should be used if you have not achieved your blood pressure goal. Here are the best first steps to take:
- Eat healthy foods -- Eat more fruits, vegetables, and whole grains. Limit intake of red meat, fried foods and high fat dairy products.
- Decrease the salt in your diet -- Limit sodium to 1,500 mg a day (about 3/4 teaspoon total). Avoid processed foods such as canned soups, deli meats and frozen dinners. A single hot dog may contain a full day’s worth of salt. On labels, look for the match between calories and mgs of salt - ideal is the same mg of salt as calories or less. If a serving is 200 calories by 600 mg of sodium, you know it is a high-salt product.
- Lose weight -- If you're overweight, losing even 5 pounds can lower your blood pressure.
- Increase physical activity -- Strive for at least 30 minutes of physical activity a day.
- Limit alcohol -- Limit alcohol consumption to 1 drink per day
- Don't smoke -- Tobacco injures blood vessel walls and speeds up hardening of the arteries. If you smoke, ask your doctor to help you quit.
- Manage stress -- Reduce stress as much as possible. Practice healthy coping techniques, such as muscle relaxation and deep breathing. Get plenty of sleep.
- Monitor your blood pressure at home -- Home monitoring can help you track your progress and avoid complications.
Have your blood pressure checked, and consult with your doctor to develop a personalized plan to manage your blood pressure if necessary. A large body of high-quality scientific evidence assembled over many years supports the benefits of taking medications to lower blood pressure if needed. Blood pressure medications work by either 1) lowering the volume of circulating blood, 2) relaxing and dilating the walls of blood vessels reducing resistance to blood flow, or 3) lowering cardiac output. Most blood pressure medications fall into the following classes:
- Diuretics -- Sometimes called "water pills," diuretics are medications that act on your kidneys to eliminate salt and water, reducing blood volume. Hydrochlorothiazide is the most common diuretic.
- Beta blockers -- These medications slow your heart rate, and reduce the workload on your heart. Common drugs include metoprolol (lopressor) and atenelol.
- Calcium channel blockers -- Some of these medications relax blood vessels while others slow heart rate. Common medications include diltiazem and amlodipine.
- Angiotensin-converting enzyme (ACE) inhibitors -- These medications relax blood vessels by limiting production of a hormone (Angiotensin II) that constricts arteries, thus lowering blood pressure. ACE inhibitors may be especially important in treating high blood pressure in people with coronary artery disease, diabetes, heart failure, or kidney failure. Common drugs include lisinopril and enalapril.
- Angiotensin II receptor blockers -- These medications relax blood vessels by blocking the action of a hormone (Angiotensin II) that narrows blood vessels. Common medications include valsartan and losartan.
- Alpha blockers -- These medications reduce nerve impulses to blood vessels, reducing the effects of hormones such as adrenaline that constrict blood vessels.
- Central-acting agents -- These medications prevent your brain from signaling to increase your heart rate and constrict your blood vessels. A common example is clonidine.