Here’s the only rule you need to know the lower, the better. “It doesn’t really matter how low your reading is, even if it’s something very, very low, like 85 systolic. As long as you’re not feeling any ill effects from it, that’s just fine, In fact, you should feel good knowing you’re in a low-risk group,” says Robert DiBianco, M.D., director of cardiology research at the Washington Adventist Hospital in Takoma Park, Maryland.
The landmark Framingham Heart Study, which took a decades-long look at the health of more than 5,200 residents of Framingham, Massachusetts, found that people with systolic blood pressure readings below 120 mm Hg (millimeters of mercury) had the least chance of suffering heart attacks. The risk rose steadily with increased pressure, People with the highest readings, 170 mm Hg or above, were over three times more likely to die of heart attacks than those at or below 120 mm Hg, Still, there are a couple of problems to watch for with low blood pressure. As people age, they’re more likely to suffer from a form of temporary low blood pressure called orthostatic hypotension-the sensation you get when you hop out of bed and suddenly feel weak, like the room is spinning or the lights are dimmed. “If you have ever fainted from that, or if it happens more than very, very rarely, you should see a doctor,” Dr. DiBianco says. The problem could be caused by mild dehydration, a reaction to medication, fever, illness or heart exhaustion, he says. For some people, especially the elderly and people with diabetes or heart disease and possibly those being treated for high blood pressure, readings that fall too low may be a particular risk. If you fit in one of these groups, consult your doctor, Dr. DiBianco says.

We’ve looked at the effects; now lets examine some of the causes. “What causes high blood pressure is the ‘$64,000 question:” Dr. Toto says. Because in more than 95 percent of high blood pressure cases, doctors can’t pinpoint the cause.
Two factors are probably at play, says Carlos Ferrario, M.D., director of the Hypertension Center at the Bowman Gray/Baptist Hospital Medical Center in Winston-Salem, North Carolina.

Heredity

If your family has a history of high blood pressure, you’re probably at much greater risk of developing it. Dr. Ferrario says researchers are getting closer to identifying the specific genes linked to high blood pressure. That would allow doctors to test whether you’re in danger. Until then, he suggests you shake your family tree a little. If you find an uncle, aunt, sister, brother, parent or grandparent with high blood pressure, be sure to get regular blood pressure checks.

Lifestyle
Even if you have heredity working against you, you may not get high blood pressure. “Very much depends on your lifestyle,” Dr. Ferrario says. Being overweight, not getting enough exercise, smoking, high-fat, high-salt diets and stress all may contribute to high blood pressure. “When you start combining those factors.
such as being overweight and smoking-the risk really begins to increase;’ Dr. Ferrario says.

Psychological factors

Your state of mind can also playa role in high blood pressure. A 20-year study of 1,123 American adults found that severe anxiety and worry make middle-aged men twice as likely to develop high blood pressure. Data for this study came from the famous Framingham Heart Study, which tracked the health of more than 5,200 adult residents of Framingham, Massachusetts. Job stress may lead to high blood pressure, too. A study of 129 working adults found that those with highpressure jobs-positions with lots of responsibility but little decision-making power-showed bigger increases in blood pressure during the workday than those with less demanding jobs. While everyone’s blood pressure rose at work, the highstress men had jumps of six points in systolic pressure and four points in diastolic pressure compared with their less stressed coworkers. Anger may playa role in high blood pressure as well, says Patrick Mulrow, M.D., chairman of the Department of Medicine at the Medical College of Ohio at Toledo and chairman of the American Heart Association’s Council for High Blood Pressure Research, though the evidence is sketchy and sometimes contradictory.
Scientists have found that the combination of too much sodium and high stress can create a powerful pressure problem. A study of 32 students at the Johns Hopkins University School of Medicine in Baltimore showed that people who ate highsodium diets and faced high-stress conditions for a two-week period saw their systolic blood pressure readings jump more than 6 points. The high-sodium, low-stress people, by comparison, saw increases of just 0.6 point, and the low-sodium, highstress people showed increases of just 0.1 point.

Kidney stones seem to burn. The flu can lay you out for days. And a broken leg? That hip-to-toe cast is hard to ignore.

You can complain all you want about health problems like these. But at least you know you have them, and that they’ll be getting fixed. High blood pressure is different: Not only is it silent, it’s far more dangerous. You can have it for years and never even know. You don’t feel any different, look any different or notice any symptoms. Yet all that time, high blood pressure can quietly be setting you up for heart attacks, strokes and even kidney failure.

“It would be nice if high blood pressure announced itself a little more clearly;’ says Robert Toto, M.D., associate professor of internal medicine at the University of Texas Southwestern Medical Center at Dallas. “But unless you somehow find out about it, a lot of damage can be done.”

When blood pressure rises, it puts stress on arteries and veins, Dr. Toto says. This can leave nicks and scratches on the linings of blood vessels, creating snags where plaque can gather. This narrows the openings in the arteries-creating even more high blood pressure as your heart tries to pump blood through smaller tubes.

When doctors measure your blood pressure, they take two readings. The first, called the systolic (the top figure), shows how hard your heart must beat to pump blood through your veins and arteries. The bottom figure, the diastolic, indicates the resistance your blood vessels exert when blood flows back to the heart.
A reading of about 120/80 is considered optimal. When blood pressure readings creep toward 140/90, doctors begin to get concerned. That’s considered borderline high blood pressure, the point at which serious health problems can start. People with high blood pressure are more likely to have a stroke and more likely to suffer a heart attack. High blood pressure also can lower the flow of blood to organs and tissue, depriving them of precious oxygen and nutrients. That’s why high blood pressure can led to kidney disease or even complete kidney failure, Dr. Toto says.
Some experts believe that decreased blood flow also can cause brain damage. Researchers took magnetic resonance images of 35 adults ages 51 to 80 and found that those with high blood pressure showed significant deadening of brain tissue on the left side and great fluid buildup on both sides of the brain. This could be a sign that their brains had actually shrunk in size~ perhaps because high blood pressure prevented small vessels from delivering enough blood and nutrients to the brain cells, according to Declan Murphy, M.D., senior lecturer and consultant psychiatrist with the Institute of Psychiatry in London. High blood pressure can even affect your sex life. Men being treated for high blood pressure are up to four times more likely to become completely impotent in later life, according to Kenneth Goldberg, M.D., director of the Male Health Center in Dallas and author of How Men Can Live as Long as Women.