If you have hypertension, your blood pressure is too high. Your blood travels through a network of arteries from your heart to the parts of your body that needs it. If the pressure of the blood flowing through your arteries is too high, it stresses your blood vessels, much like a bicycle tire or balloon is stressed when inflated with too much air. Ideally, your heart pumps with just enough force to move the blood smoothly and swiftly throughout your body. But if your heart pumps with a force that is too great to keep the blood flowing smoothly, the pressure builds up in the artery.
Think about what happens when you run water through a tube at a steady, even flow. If you constrict the tube by narrowing the opening or if you turn up the faucet, the water pressure builds and the tube become stressed and may even contort. This is what happens to your arteries. Over time, your whole circulatory system becomes taxed.
There are two types of hypertension: essential and secondary.
Essential hypertension has no apparent cause. Secondary hypertension is caused by some specific and recognizable event, such as kidney disease, pregnancy, oral contraceptive use, certain drugs, alcohol abuse or a hormonal disorder. The vast majority of people with high blood pressure have essential hypertension.
But how much is too much? How do you know you have high blood pressure? Your doctor or health care provider measures your blood pressure in your upper arm with a blood pressure cuff, usually on your regular visit. The pressure of your blood against your arterial wall is measured as your heart contracts to pump out blood (systolic) and as it relaxes to permit the blood to flow (diastolic). The pressure is reported as the systolic pressure over the diastolic pressure. If your doctor tells you your blood pressure is 140/75 or 140 over 75, this means your systolic pressure is 140 and your diastolic pressure is 75.
Whether or not you have high blood pressure depends on the values of these readings. In general, when your systolic pressure rises above 130 and diastolic pressure rises above 85, you have mild hypertension. The higher these values, the more severe your hypertension.
To get an accurate reading, your blood pressure should be measured with a properly fitting cuff. Also, some people experience a rise in blood pressure when they visit a doctor’s office. This phenomenon even has a name: white coat hypertension. If you feel tense just from the act of having your blood pressure measured, try taking your own blood pressure measurements with a home blood pressure meter. Keep your own records to show your doctor
There are no symptoms of mild to moderate hypertension. You probably feel fine and may be unaware that anything is wrong. If you have severe to very severe hypertension and you have had it for some time, you may begin to notice headaches, palpitations, dizziness and an overall feeling of fatigue or just feeling not quite right. However, some of these symptoms are caused by damage to organs and systems in the body as result of high blood pressure, not by the high blood pressure itself. The only way to know for sure whether you have high blood pressure is to have your blood pressure measured on several different occasions, preferably a week apart, by your doctor or member of your health care team. If your blood pressure is over 140/90 on several different occasions, you probably have hypertension.
If you have high blood pressure, you are at a greatly increased risk for heart failure and heart attack, kidney failure and, especially, stroke. If you have high blood pressure, you are four times more likely to have a stroke than someone without high blood pressure. Even mild hypertension can lower your life expectancy, and severe hypertension can shorten your life dramatically. For example, if you have malignant hypertension, a very severe form of high blood pressure, and it is left untreated, you are at considerable risk of dying within a matter of months. Fewer than 5% of people with malignant hypertension survive for a year.
Factors that increase your risk of high blood pressure include a genetic predisposition, increasing age, a sedentary lifestyle and obesity. African Americans are twice as likely to have a high blood pressure as Caucasians, and women are less likely than men. Stress, excessive alcohol consumption, and too much salt in your food can also contribute, especially if you are predisposed to high blood pressure.
What You Should Do
You should have your blood pressure checked regularly, especially if you have diabetes or any of the risk factors associated with hypertension. If you have any of the symptoms associated with severe or very severe hypertension, see your doctor right away. You could have malignant hypertension, a life-threatening condition that requires immediate treatment. If you are experiencing any symptoms, it means that your organs, especially the kidneys, heart, blood vessels and brain may be damaged. You should be treated right away to avoid further damage.
Once your doctor establishes that you have high blood pressure, she will assess whether any of your organs have been damaged. Your retina will be directly examined for retinopathy using an ophthalmoscope. Often a doctor can tell how serious your hypertension is by looking at the condition of your retinas. Your doctor will examine your heart, using an electrocardiogram, echocardiogram, and/or chest X ray. High blood pressure can cause the heart to enlarge. Kidney damage may be assessed by assaying the urine. The presence of protein or blood cells in the urine is an indicator of kidney damage. Your doctor may also check your kidneys in a physical exam and by X ray or ultrasound.
If your high blood pressure is mild to moderately high, your doctor will suggest that you modify certain lifestyle factors. If you are obese, your doctor will suggest you lose weight. Cutting out salt in the diet, reducing alcohol consumption, quitting smoking and increasing the amount you exercise are some of the steps you can take to lower your blood pressure.
If none of these interventions helps, or if your blood pressure is severe, your doctor may prescribe a drug to lower blood pressure. Your doctor will prescribe a drug based on many factors, such as your age, sex, and race, as well as lifestyle factors. If you have kidney disease, your choice of drugs may be limited, because certain drugs can cause further kidney damage. And some drugs can upset your blood glucose control and should be avoided if you have diabetes. You may find that you have to try different medications to find the one that works for you.
Your doctor may very well prescribe a thiazide diuretic as a first approach to controlling high blood pressure. These drugs work by helping the body get rid of excess salt and water. This decreases the total volume of fluid in the body and thus lowers blood pressure. However, these drugs can also lower potassium levels. You may be advised to take a potassium supplement while on thiazide diuretic. These drugs are especially effective in African Americans, the elderly, obese people and those with kidney or heart failure.
Adrenergic blockers are a class of drugs that block the body’s response to stress. Normally, your body reacts to stress by causing a rise in blood pressure. But adrenergic blockers prevent this rise in blood pressure. Beta-blockers are the most common adrenergic blockers, and they work well in Caucasians, young people and people who have had a heart attack, rapid heartbeat, or migraine headaches. Alpha-blockers work by helping blood vessels relax. They do not appear to affect blood glucose levels and may also have a positive effect on blood lipids. However, if you are prescribed an alpha-blocker, your doctor will advise that you use caution. For many people, the first dose can cause blood pressure to drop precipitously. You doctor may start you on a small dose of this drug.
The ACE inhibitors work by blocking the conversion of an enzyme, angiotensin I, to angiotensin II. Angiotensin II causes arteries to constrict, which increases blood pressure. By blocking the formation of this enzyme, ACE inhibitors work to dilate the arteries. The ACE inhibitors work well in people with kidney disease and protein in the urine. They do not affect blood glucose control and do not increase lipid levels.
However, in rare cases, ACE inhibitors can worsen kidney function when both arteries to the kidneys are constricted. Angiotensin II blockers more directly block the action of angiotensin II. The results are similar to those seen with ACE inhibitors—a lowering of blood pressure by dilating the arteries—with fewer side effects.
Calcium channel blockers are also sometimes prescribed for people with high blood pressure. Although they do not appear to affect blood glucose or lipid levels, they should be used with caution. In some people, they can dramatically decrease blood pressure when you stand up, a condition known as orthostatic hypotension. Some calcium channel blockers can worsen the proteinuria found in kidney disease, but others seem to decrease it. For this reason, some doctors do not recommend using some types of calcium channel blockers for people with diabetes.
If you have malignant hypertension, a life-threatening condition in which your blood pressure must be lowered immediately, you may be given one of several drugs intravenously. These drugs include diazoxide, nitroprusside, nitroglycerin and labetalol. Nifedipine, a calcium channel blocker, is fast acting and can be given orally, but it can cause very low blood pressure and must be used with caution.
The best way to prevent high blood pressure is to maintain a healthy lifestyle. If your blood pressure is already high, modifying certain lifestyle factors can help bring it down. If your blood pressure is in the normal range, keeping fit and eating right can go a long way in preventing high blood pressure from developing.
If you smoke, quit smoking. If you are overweight, losing weight will improve your blood pressure. You may need to reduce the amount of calories you consume, decrease the amount of fat in your diet, and increase the amount you exercise. If you have diabetes, this should be done carefully, with the supervision of your doctor and dietitian. The good news is that modifying these factors will also improve your diabetes control and reduce your risk of stroke and heart attack.
If you drink alcohol, drink only in moderation and talk to your dietitian about how to make this a part of your diabetes control plan. Also, reduce your salt intake and try to reduce the stress in your life as much as possible. Because high blood pressure is a risk factor for other conditions such as heart disease and stroke, preventing it from occurring in the first place will also help reduce the risk of some of these other complications of diabetes.
Sources and References
The Diabetes Problem Solver—Quick Answers to Your Questions About Treatment and Self-Care by Nancy Touchette
Hypertension and exercise by Jorge Ruivo and Paul Alcântara
Secondary Hypertension: Novel Insights by Konstantinos Tziomalos
Hypertension in the elderly by Nicolas Robles and Juan Macias