Don’t blow a gasket; adjust your life
Studies consistently show that lowering blood pressure significantly lowers the risk of stroke and also, though less dramatically, the risk of heart attacks, heart failure and kidney problems.
Drugs may be necessary sometimes, especially when blood pressure is dangerously high, but other things can help. Maybe you need to exercise a little harder and eat a little less (or sleep a little longer and stress a little less).
As you read, bear in mind: The evidence for blood pressure-lowering is stronger for some lifestyle measures than others.
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Blood pressure basics
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Blood pressure is measured in millimeters of mercury (mm Hg) at two points: when the heart beats (systolic) and between beats (diastolic). The systolic reading is usually stated in front of (or over) the diastolic one, for example, 110/75 mm Hg. Both numbers matter; after age 50, systolic becomes more key as it indicates how flexible your blood vessels are.
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If your systolic blood pressure is 140 or higher, or your diastolic is 90 or higher, you have high blood pressure, or hypertension. If your systolic is between 120 and 139 or your diastolic is between 80 and 89, you have prehypertension -- you’re at risk of developing high blood pressure, and your health risks are already elevated. If you have diabetes or kidney disease or have had previous cardiovascular problems, such as a heart attack or stroke, 130/80 mm Hg is the threshold for high blood pressure. About one-third of American adults have high blood pressure. Among those age 55, more than 90% either have it or will develop it.
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Blood pressure fluctuates all day -- it goes down when you nap at your desk and comes back up (and then some) when your boss yells at you to wake up. “High blood pressure” refers to pressure that is chronically high. One bad reading isn’t conclusive; doctors generally recommend several for a diagnosis.
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High blood pressure is not usually curable. Even if you can get your pressure back below 120/80 mm Hg, you still have the condition and still need to treat it.
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The DASH diet
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DASH stands for Dietary Approaches to Stop Hypertension, an eight-week clinical trial, reported in 1997, that tested the effects of three diets on 459 adults. Among the group, 133 had high blood pressure for which they were not being treated with a drug.
One diet (the “control”) was fairly similar to what many Americans eat; another was similar to that but with more fruits and vegetables and fewer snacks and treats. The third, which came to be known as the DASH diet, was rich in produce but also included a lot of low-fat dairy products and whole grains, as well as less saturated fat, total fat and cholesterol.
The fruit-and-vegetable group reduced their blood pressures compared with the control group, but the effects were greater for those in the DASH group, who reduced their blood pressure readings by averages of 5.5 mm Hg systolic pressure and 3 mm Hg diastolic pressure compared with the control group.
Reductions in blood pressures occurred for those who had high blood pressure (140 mm Hg or more) and those who didn’t. But those who had high blood pressure lowered their blood pressure by about twice as much as the overall average.
The authors noted that the effects of the DASH diet were comparable to the effects of a single blood-pressure-lowering drug and speculated that, if everyone ate that way, the occurrence of heart disease and stroke could go down by 15% and 27%, respectively.
Attempts to show that the DASH diet reduces bad outcomes -- things like death and strokes as opposed to just high blood pressure -- haven’t always been conclusive. But a 2008 report suggested the diet does lower the risk of heart disease and stroke, and two studies published last year found that it lowers the risk of heart failure in men and women.
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Stress reduction
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Everyone agrees that stressful situations make your blood pressure take off. It’s the fight-or-flight, prepare-to-do-something-dramatic response your ancient ancestors had when being charged by a woolly mammoth. Your body releases stress hormones that make your heart beat faster and your blood vessels constrict, and blood pressure rockets. When the stressful situation is resolved, blood pressure comes back down.
Some scientists suspect that getting stressed out too often can lead to chronic high blood pressure. That’s not proved. But whenever blood pressure is higher than it should be, it increases wear and tear on the blood vessels. So a plethora of stress, leading to a plethora of blood pressure spikes, can do the same sort of damage that high blood pressure can do.
Plus scientists know that in stressful situations, people often smoke, drink and eat too much of the wrong foods -- all activities that can increase the risk for high blood pressure.
The effect of stress reduction on blood pressure isn’t clear. Some studies have found that lowering blood pressure may be as simple as slow, regular breathing (aided by a device that played musical tones to guide breath rate in one report). On the flip side, a 2008 review concluded there was little reliable evidence that relaxation strategies reduced blood pressure, and a 2007 report concluded the same about meditation. (Another, in 2008, concluded that transcendental meditation may be an exception. Perhaps significantly, this meditation calls for slow, controlled breathing.)
One way to keep a lid on your blood pressure may be to adopt a pet. A 2000 study of 48 stockbrokers taking medicine for high blood pressure gave some of them pets as well. After six months, blood pressure rose for all subjects in a high-stress situation, but for those with pets it crept from 120 to 126, compared with a jump from 120 to 148 for the others.
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Exercise
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Dozens of studies have reported a link between exercise and lowered blood pressure: Some have found reductions of up to 10 mm Hg (systolic) and 6 to 10 mm Hg (diastolic) blood pressure units in people who already have hypertension.
In general, reductions are not as great for people with blood pressure in the normal range: A Belgian review of scores of studies found that for people with high blood pressure, average reductions from exercise were 6.9 mm Hg systolic and 4.9 mm Hg diastolic, and for participants who did not have high blood pressure, only 1.9 mm Hg and 1.6 mm Hg.
Age seems to matter. In one study, exercise did not reduce systolic blood pressure in older people -- ages 55 to 75 -- although it did reduce diastolic pressure. (Both readings are important.)
A possible reason: Systolic blood pressure increases as arteries grow stiffer, which happens as people age, and exercise did not reduce artery stiffness in the study participants.
Most studies about the effects of exercise have looked at aerobic exercise, although resistance training may also be effective. Recommendations call for exercising every day (or at least most days) for 30 to 45 minutes. Moderate exercise may be as effective, and possibly more so, than higher-intensity exercise.
Blood pressure can drop in just a few weeks of regular exercise. It can also pop right back up if you stop exercising.
During the exercise itself, it’s normal for blood pressure to rise. But some people who have normal or only slightly raised blood pressure can experience abnormal spikes during exercise that may be a sign of high blood pressure to come. Such spikes are more likely to occur in those whose blood vessels are too stiff to expand to accommodate the increased blood flow that accompanies exercise -- a sign of early artery disease.
Just why exercise lowers blood pressure isn’t clear, but there are several possibilities. Exercise makes the heart stronger, so it doesn’t have to pump as hard, which in turn lowers the force on your arteries. Exercise reduces blood insulin levels, and high blood insulin has been linked to hypertension.
And regular exercise reduces blood levels of the hormone adrenaline. That, in turn, lowers blood pressure and heart rate.
You should consult your doctor before beginning an exercise program, especially if you already have high blood pressure.
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Sleep
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It’s wise to pay attention to your blood pressure -- but don’t lose sleep over it. That may make matters worse. A five-year study published last year found that among nearly 600 adults (average age 40 at the start of the study) the fewer hours of sleep people got, the higher their blood pressure was likely to be and the more likely it was that their blood pressure would increase over time. For every hour less sleep participants got, their chances of developing high blood pressure over the study period zoomed up by 37%.
Another study of more than 10,000 adults ages 35 to 55 found that women who averaged six hours of sleep a night were 42% more likely to develop high blood pressure than women who averaged seven hours -- though it found no such effect for men. A 2006 study reported a similar finding for both genders: Of those who slept five hours a night or less, 24% developed high blood pressure during eight to 10 years of follow-up, versus 12% of those who slept seven or eight hours.
The reasons for this effect of sleep aren’t clear, although it is known that blood pressure typically drops during sleep and thus brings down the average blood pressure for the day.
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Potassium, fish oil, fiber
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Results haven’t been unanimous, but a good deal of research suggests that healthy doses of potassium can help lower your blood pressure.
A 2001 study based on data from more than 17,000 U.S. adults, for example, found that people who ate 8.5 servings a day of fruits and vegetables (about 4,100 milligrams of potassium) had lower blood pressures than people who ate 3.5 servings (1,700 milligrams) -- by an average of 7.2 mm Hg systolic and 2.8 mm Hg diastolic units. (One contributing factor in the success of the DASH diet may be potassium-rich fresh fruits and vegetables.)
An Institute of Medicine panel recently recommended that adults should have at least 4.7 grams of potassium daily unless they have medical conditions that preclude it. This is about twice as much as most American adults get. Studies suggest that the ratio between potassium and sodium may be more important than the absolute levels of either -- 2-to-1 is the target.
Other studies have suggested blood-pressure-lowering effects for fish oil and fiber. Oily fish such as salmon and sardines are good sources of fish oil, but high doses can increase the risk of bleeding, so it’s wise to consult a healthcare provider before taking supplements. Good sources of fiber include whole grains, especially bran, beans and many fruits and vegetables.
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Salt
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Everybody needs salt, but health experts generally agree that most Americans get too much of it. Excess salt can lead to excess fluid retention in the blood. This makes the circulatory system “fuller” and the pressure inside it greater. Salt can also make small blood vessels called arterioles contract, which effectively shrinks the circulatory system, again increasing pressure.
A Jan. 20 report in the New England Journal of Medicine concluded that if everyone in the United States consumed half a teaspoon less of salt every day, every year the number of new cases of coronary heart disease would drop 60,000; of stroke, 32,000; and of heart attack, 54,000 -- and the number of deaths from any cause each year would drop by 44,000.
But, in fact, the relationship between salt and high blood pressure is complicated. In some “salt-sensitive” people, blood pressure responds dramatically to changes in salt intake. In others, not so much.
Summarizing vast amounts of research in this area, authors of a 2006 article in the Journal of the American College of Nutrition (part of a special issue on the health effects of salt) wrote that in the general population, “careful observations using sophisticated techniques have revealed only a weak relationship between sodium intake/excretion and blood pressure.”
It’s hard to tell who’s salt-sensitive. There’s no simple test. But many factors seem to matter, including family history, age, weight, diet and race and ethnicity.(African Americans are more likely than others to be salt-sensitive.)
The reasons for salt sensitivity aren’t well understood, but it’s thought that if the body’s own blood-pressure-regulating systems become compromised in some way, the effects of salt on fluid retention and blood vessel contraction are left to rule the day.
Given the ambiguities, most medical experts say that limiting salt consumption is a good general rule. Between 1,500 and 2,300 milligrams of sodium a day are considered plenty for healthy adults (that’s a teaspoon of salt or less); if you’re older than 50 or African American, or if you have other risk factors for salt sensitivity, you should stick to the low end of that range.
“That can be difficult, especially if you eat out often,” says Dr. Mitra Nadim, director of the Hypertension Center at USC. More than 75% of the sodium in the average American diet comes from processed and prepared foods.
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Weight loss
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As people gain weight, their blood pressure tends to go up. Fortunately, as they lose weight, their blood pressure tends to go down -- but only so far, says Dr. Karol Watson, co-director of preventive cardiology and director of the hypertension clinic at UCLA. “If your body weight is normal, getting below doesn’t help,” she says.
Even modest weight loss (say, 5% to 10% of your current heft) is effective at lowering blood pressure for those who have high blood pressure or prehypertension. But the way you lose the weight may matter.
A 2006 review of 17 studies reported that people who lost modest amounts of weight through diet alone, or diet plus the “fat-blocker” orlistat (Xenical, Alli), did experience blood pressure drops. But those who used the appetite suppressant sibutramine (Meridia) did not -- in fact, in some cases, the blood pressure of people taking sibutramine went up.
And in a yearlong study reported Jan. 25 of 146 obese and overweight people, those who lost weight on a low-carbohydrate diet had a greater reduction in blood pressure than those who lost the same amount of weight through a low-fat diet combined with prescription-strength orlistat. That was the case even though both groups shed about the same number of pounds -- about 10%, on average, of their starting weight. Doctors were able to reduce or discontinue blood pressure medication for 47% of the low-carb group -- but for only 21% of the low-fat-and-orlistat group.
Though the association between weight and blood pressure is well established, it isn’t well understood. Many believe it’s related to food. “If you’re overweight, you’re usually not eating the healthiest diet,” says Dr. Mitra Nadim, director of the Hypertension Center at USC.
But a 2002 study suggests it may be related to decreases in amounts of angiotensin-converting enzyme, or ACE, which plays an important role in blood pressure regulation.
Levels of ACE went down an average of 18% in the study, which tracked 16 obese adults as they shed 5% to 10% of their body weight over five weeks.
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Alcohol, smoking and caffeine
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Is having a bad habit ever a good thing? It kind of can be if your aim is to lower your blood pressure, since one way to do that is to reduce your alcohol consumption significantly. It’s a winning strategy -- but only, of course, if you were drinking a lot in the first place.
Many studies have documented the link between alcohol and blood pressure. A 2001 review of 15 alcohol-reduction trials with 2,234 participants concluded that cutting back on alcohol led to reductions in systolic and diastolic blood pressures. The greater the alcohol reduction, the greater the blood pressure reduction.
Some scientists believe that red wine, in moderate amounts, may improve vascular function and have a less harmful effect on blood pressure than other forms of alcohol -- maybe even a positive effect. But this was not supported by a 2005 study that found red wine and beer increased systolic blood pressure by about the same amount.
Any time you smoke a cigarette, it can produce an immediate (but temporary) surge in blood pressure due to the nicotine. There’s no evidence that smoking increases the risk of chronic high blood pressure, but smoking plus high blood pressure appear to have a greater-than-additive effect on the risk of hemorrhagic stroke. So quit, already.
Caffeine can make blood pressure rise temporarily, especially if you’re not used to it. But there’s no definitive evidence that a cup (or two) of coffee a day raises blood pressure over the long haul. Some research suggests heavy caffeine consumers get used to it, so their blood pressure doesn’t react as much anymore.
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