Almost one in three American adults has high blood pressure. For black Americans, it's closer to four out of ten adults.

These numbers are even more alarming when you realize that only a third of people with high blood pressure have it under control and another third don't even know they have it.

**The Silent Killer**

Although it has no symptoms, high blood pressure can cause stroke, heart attack, and kidney failure. That's why it's called "the silent killer." It's also considered a risk factor for developing dementia.

Blood pressure is the force pushing against the artery walls by the flow of blood. It's measured as two numbers given in millimeters of mercury (mm Hg), such as 140/90 mm Hg (which is said as "140 over 90").

The top number, 140, is the systolic reading, or the highest pressure reached when the heart beats. The bottom number, 90, is the diastolic reading, or the lowest pressure when the heart relaxes between beats.

The medical community used to define normal adult blood pressure as below 140/90.

Now they've revised that to less than 120/80. Anything between 120/80 and 140/90 is considered to be prehypertension. Supposedly, this indicates a high risk for developing hypertension.

So it was a surprise to many people when they went from being healthy to being prehypertensive simply because doctors had changed their blood pressure classifications.

**The Surprising Killer**

But here's a shocking fact that kills no matter how the doctors classify it.

Did you know that a person who usually has normal blood pressure can experience a sudden spike that can kill him?

It's true.

Strenuous weightlifting - e.g., bench-pressing more than half your body weight - can cause your systolic pressure to spike to 300 mm Hg or more. Especially if you hold your breath while lifting.

Other risky activities are vigorous sports like squash or racquetball.

Weightlifting and other vigorous sports don't cause permanent high blood pressure. So how does a temporary surge in pressure kill you?

Well, it could cause a stroke, a deadly tear in your aorta, or aortic dissection.

A tear in your aorta, the main artery in your heart, usually occurs if you have an undetected aneurysm, which is a bulge in the aorta. Most people with an aneurysm don't know they have one.

Aortic dissection happens when the walls of the aorta split and blood enters between the layers. You'll feel an excruciating, knife-like pain. Only immediate surgery can save your life.

So if this type of weightlifting or intense aerobic activity can kill a person with normal blood pressure, it can be even more dangerous if you already have high blood pressure.

**Get Yourself Checked**

That's why it's so important that everyone, whether healthy or not, have his or her blood pressure checked regularly by a physician or other healthcare professional. You should also discuss your exercise routine with your doctor to make sure it's safe for you.

There are two types of persistent high blood pressure, essential hypertension and secondary hypertension. Only your doctor can tell you which type you have.

**Weight Can Be a Factor**

Essential hypertension is high blood pressure for no apparent reason, although diet, excess weight, and heredity may be contributing factors. About 95% of people with high blood pressure have essential hypertension.

The second kind of high blood pressure, secondary hypertension, is caused by some other medical disorder such as kidney disease. If your doctor can treat the underlying condition successfully, secondary hypertension will often disappear.

If the underlying cause can't be eliminated, then doctors often treat secondary hypertension the same as essential hypertension.

The use of blood pressure-lowering drugs is recommended at levels of 140/90 mm Hg or higher.

**Watch Out for Side Effects**

But the medications can have unpleasant and possibly dangerous side effects, especially at higher dosages or if a combination of drugs is used.

And it may take a few tries before your doctor finds the dosage or drug combination that is right for you.

In my family, we know the dangers of these medications firsthand. We also know the tragedy that high blood pressure can cause.

My maternal grandmother had high blood pressure for decades. Even with medication, it was never completely controlled. She died of a stroke at 85.

So when my mother developed high blood pressure, we knew we couldn't wait to treat it. But she didn't want to take drugs. Instead, we tried a dietary approach.

In just 7 weeks, her blood pressure dropped to 132/68 from 168/88. Without medication or exercise.

And eventually, her blood pressure declined to 112/64.

But everyone is different. You should consult your doctor to decide which approach - medication, diet, exercise, or otherwise - makes the most sense for you.

**Important Disclaimer: This information is presented for educational purposes only. This isn't medical advice and it's not a substitute for any advice or treatment from your physician. You should always see your doctor before starting any treatment - drug, diet, exercise, or otherwise - for high blood pressure or any other medical condition.