Hypertension is the medical term for high blood pressure. It means prolonged and persistently elevated blood pressure, even when you’re relaxed and feel well.

Unless it becomes severe, hypertension isn’t an illness or disease you can feel. You’re not sick. Instead, it’s a condition of risk. It’s like driving 90 miles per hour wherever you go. You’re fine, your car is fine, everything is great — until you crash.

A more technical example is the water pressure regulator in your home. The pipes inside your house were designed be exposed to water pressure no greater than about 70 PSI. The pressure in the city water system is a lot higher, maybe 120 PSI. So there’s a device where the water enters your home that looks like two miniature pie plates bolted together. It’s the water regulator and is responsible for limiting the pressure in the pipes within your home.

If the water regulator malfunctions, all the pipes in your home become exposed to full street pressure, much more than they can safely withstand. But all your plumbing still works normally, maybe even with an extra “snap.” There’s no problem at all! Until . . . a pipe explodes and you have a major mess.

So with hypertension. This is a condition without symptoms. You feel fine, but persistently elevated blood pressure causes silent damage to your heart, kidneys, brain, and blood vessels. Every ten points of elevated blood pressure doubles your risk of a heart attack or stroke. You won’t know until it’s too late, when you have a stroke or heart attack, or you learn of kidney failure or accelerated hardening of the arteries.

How do you know if you have hypertension?

The normal blood pressure is measured in millimeters of mercury (“mmHg”). Barometric pressure (used to forecast weather) is also measured in millimeters of mercury and commonly runs about 730 mmHg. The “normal” blood pressure is 120/80 mmHg. This looks like some kind of mathematical equation, but it’s really quite simple. The two numbers are as high as the pressure goes when your heart pumps during a heartbeat, then as low as it goes between heartbeats. In short, the numbers mean “as high as it goes, slash, as low as it goes.”

(Using medical terminology, the period when the heart is beating is called “systole,” and between heartbeats is called “diastole.” So the peak of the blood pressure is called the systolic blood pressure. The lowest point is the diastolic blood pressure.)

As it turns out, normal blood pressure varies all over the place. My favorite examples are that it reaches 300/150 when you’re making love and 80/60 when you’re asleep. Typically, blood pressure goes up when you’re upset, exercising, in pain, laughing aloud, or having an excited conversation. The 120/80 norm is the “resting blood pressure.” This means when you’re in neutral, nothing particular going on, sitting quietly and comfortably.

Many of my patients insist they can feel when their blood pressure is elevated. They’ve been checking their blood pressure at home and will tell you it goes up whenever they feel bad. “I had a headache. I checked my blood pressure and sure enough it was elevated. That high blood pressure was causing my headache!” Of course, this is exactly backwards. Their pain caused the blood pressure to go up, not the other way around. Elevated blood pressure is silent; it causes no symptoms at all.

So when is an elevated blood pressure considered hypertension? And which counts more, the high number (systolic blood pressure) or the low number (diastolic blood pressure)?

My reading of the medical evidence is that both numbers count equally. So I do something a little weird: I add them together. If you add 120 and 80, you get 200. Any added-together blood pressure between 180 and 210 is normal. So if you’re 100/70 or 135/75, you’re fine. (Healthy young women are often even lower, with sums in the 150-180 range.)

Numbers between 211 and 220 are okay for most but too high for high-risk people, like those with diabetes. Examples include blood pressures like 140/80 or 130/90.

Between 221 and 230 is elevated but doesn’t require medications in most. Sample blood pressures in this range are 145/85 and 130/100. If you’re at increased risk from atherosclerosis (obese, smoker, abnormal cholesterol, family history of heart disease), you should be treated. Some physicians now call the 211-230 range “prehypertension”: you’re heading towards genuine high blood pressure.

Sums of 230 and higher require medical treatment in almost everyone.

I would add about 20 points to all these figures for people over age 75, because they are more sensitive to blood pressure being too low.

A common complicating issue is “white coat hypertension.” Here, blood pressure shoots up whenever you’re in the doctor’s office but is normal everyplace else. Because your pressure is almost always normal, you don’t have true hypertension, but it can be hard to tell without measuring blood pressure at home. Patients with this problem may receive medication they don’t need. (But most of my patients who insist they have white coat hypertension actually are genuinely hypertensive.)

Check your blood pressure at home

Because blood pressure varies so much anyway, and to prevent needlessly treating white coat hypertension, I strongly recommend that anyone concerned about blood pressure measure it at home. Buy an automatic blood pressure machine at your pharmacy, Target, Wal-Mart, or Costco. It should be fully automatic, so that all you have to do is put on the cuff and press a button. Be sure it has a cuff that goes around your arm — wrist or finger machines are inaccurate. Buy a name brand, something you’ve heard of, or check out Consumer Reports.

While 90% of home blood pressure machines are accurate, it’s important to verify yours is giving you true readings. First, when you get it home, take several blood pressures in a row. These should be similar to each other, not 100/80 one time and 160/90 a moment later. Second, bring your machine to our office so we can verify its accuracy. Please do not measure or record your blood pressure at home if your machine is inaccurate. If you do, you’ll fall into the trap of believing something that isn’t true.

The 120/80 normal blood pressure standard is the reading in the doctor’s office. When you measure your blood pressure at home, it should be a little lower, typically 5-10 points in the high or low (systolic or diastolic) numbers or both.

What causes hypertension?

Most people with high blood pressure have “essential hypertension,” which means nobody knows what causes it. Essential hypertension typically begins between the ages of 35 and 50 and becomes more common and (unless treated) more severe as one gets older. It is extremely sensitive to being overweight, but even thin people can be genuinely hypertensive. As America grows heavier, essential hypertension is becoming more common, and it must be treated.

About 15% have “secondary hypertension,” which is elevated blood pressure caused by another condition. The most common cause of secondary hypertension is heavy drinking: two drinks or more a day. Kidney disease often increases blood pressure, and a host of rare endocrine conditions can do it as well. Finally, in men over the age of 40, obstructive sleep apnea is an important cause of hypertension.

Because other illnesses can cause hypertension, it’s important at some point to have a physical examination and labs looking for the more common underlying causes. This is particularly important if you’re under the age of 35 or your blood pressure is difficult to control.

How do you treat hypertension?

As I describe below, a number of simple measures can reduce elevated blood pressure, sometimes even without medication. It’s worth trying to lose weight, exercise, or cut back on salt. I don’t know of any other vitamins, minerals, or herbs that reduce blood pressure substantially.

Almost everybody with hypertension needs prescription medications. Patients rarely have side effects from these drugs, although sometimes we have to try two or three different prescriptions before finding the approach that’s best for you.

There are five major classes of prescription antihypertensive medications: ACE inhibitors, angiotension-receptor blockers (ARB), diuretics, beta-adrenergic blockers, and calcium channel blockers. Each class is represented by a dozen or more different drugs on the market. Side effects are similar within each class but differ a good deal between classes. A host of additional types of medications are available as well but are used less frequently.

These drugs reduce blood pressure safely in the vast majority of patients and are proven to save lives. Except for angiotensin-receptor blockers (ARBs), all are available in inexpensive generic form. A detailed discussion of the various blood pressure medications is much larger than could fit here.

A majority of hypertensive patients require two different medications to control their pressure. When possible, I prefer drugs you can take once a day that have minimal or no side effects. Once your blood pressure is well controlled, it’s important to have follow-up visits every 3-4 months with labs to verify that the medications are working properly and you’re doing well.

What about side effects from these medications?

The vast majority of my patients have no significant side effects from drugs taken for hypertension. Their worst problem is remembering to take the pill, and refilling the prescription every few weeks. Sometimes people do have symptoms due to the drugs, which vary by drug class:

  • Beta-adrenergic blockers can cause fatigue, edema (swelling in the ankles), and erectile dysfunction. Beta blockers can make asthma or emphysema worse. Yet they can be particularly helpful if you’re often anxious, because they blunt the effect of anxiety on your body. I don’t use beta blockers frequently. Recent studies have shown them to be less effective than other blood pressure agents. This is especially true of atenolol.
  • Diuretics relieve edema but rarely can cause erectile dysfunction. You shouldn’t take them if you’re allergic to sulfa. Diuretics hydrochlorothiazide or chlorthalidone are my favorite second medications for hypertension. Diuretics can lower the potassium level in your blood. (Potassium is a mineral.)
  • Sometimes people develop edema or constipation from calcium-channel blockers, but they are highly effective blood pressure agents.
  • The commonest side effect from ACE inhibitors is a mild dry cough that doesn’t make you ill, but sometimes coughing repeatedly awakens you from sleep. Switching to an ARB resolves this problem, but ARBs are more expensive. Either drug can raise the potassium level in your blood.

How long must I take these *#@! drugs?

Many of my patients hope to be able to take their blood pressure pills for a little while and then poof! their blood pressure is cured. Afraid not. It’s like gas in the car: if you want it to keep running, keep adding gas. A few people can stop medication safely if they lose weight, but usually we’re talking 20-40 pounds or more. On the other hand, many people find that every few years they need moremedication, particularly if they gain weight.

Can’t you treat blood pressure without medication?

Several non-drug treatments have been shown to lower blood pressure. Most are only modestly effective, lowering blood pressure by only 10-15 points. Most of them require that you keep doing the same thing day after day to lower blood pressure. So in the end, my patients usually find it’s a lot easier to take medication. Here’s the list:

  • The most effective non-drug treatment is to lose weight and keep it off. Sometimes 10-15 pounds is enough, although often you must maintain a loss of 20-40 pounds or more. The problem is most people are much better at losing weight than keeping it off for more than a few months.
  • Many people who are markedly obese and have bariatric (weight-loss) surgery can stop taking blood pressure drugs permanently.
  • If you drink alcohol, cut your intake to one drink a day — less if you’re over age 70. This can dramatically lower blood pressure. (But many of my alcoholic patients are disappointed when they still need to take blood pressure medication when they sober up. Stopping drinking works about half the time, and often blood pressure is easier to control even if it still requires treatment.)
  • Vigorous exercise is often modestly helpful.
  • A low-salt, high-potassium diet may help. Lots of fresh fruits and vegetables helps, but in America it requires a tremendous effort to eat a low-salt diet. (Warning: if you have kidney disease or take certain medications, consuming too much potassium can be dangerous. And taking over-the-counter potassium supplements is a great way to wind up in emergency surgery to repair a hole in your intestine. Get a doctor’s help before starting this.)
  • Prayer and meditation can help drop blood pressure somewhat.