12/09/2011 Nutrition & Recipes
The term “lifestyle disorder” had to be invented to describe hypertension. Almost no aspect of daily life – diet, sleep, exercise, work, and stress – can be implicated. Your blood pressure responds to these things quite sensitively. This implies an optimistic attitude, because for many sufferers, a change in lifestyle serves as good prevention. But optimism is lost if lifestyle changes are not kept up for a lifetime. For millions of patients, the arrival of high blood pressure as they get older comes at a stage when prevention may be too little, too late.
It took a while before lifestyle disorders were recognized for what they are, a product of “normal” living that turns out not to be normal so far as the body is concerned. To previous generations of doctors, a creeping rise in blood pressure, for example, was considered normal with each decade of life. It was overlooked, or shrugged off, that hypertension needs a long span of years to cause damage and that even marginal hypertension – blood pressure on the border of being high – threatens the body almost as much as the full-blown disorder.
The Silent Killer
Because every cell is affected by the fluid pressure inside your body, let’s look at how a necessary condition turns damaging. Hypertension is publicized as the “silent killer” for its absence of symptoms detected by the afflicted person. The condition may go unnoticed for years, with few if any signs of discomfort – unlike the cartoon character sending his blood pressure through the roof, steam doesn’t come out of your ears, your face doesn’t turn red, and you don’t swell up. Generally speaking, nothing hurts.
Hypertension often isn’t seen as the culprit until a serious medical problem appears. It is a dangerous disease in its own right, however, with multiple complications. Hypertension can permanently damage the eyes, lungs, heart, or kidneys. Malignant (i.e., highly elevated) blood pressure is deadly: without treatment fewer than 10% of peoplewith malignant hypertension survive for more than 1-2 years.
As to its frequency, high blood pressure is extremely common in the US and throughout the developed world. About 30% of adults aged 18 or older in the US have hypertension, about the same percentage as in other developed nations. African Americans have higher levels (42%) than non-Hispanic whites (29%) and Mexican Americans (26%). With the rise in childhood obesity, lack of exercise, and poor diet, the age at which blood pressure begins to rise has gotten younger. (There isn’t a simple target blood pressure reading that indicates high blood pressure in children, because what’s considered normal blood pressure changes as children grow.) About half of adults with hypertension don’t have their blood pressure under control.
Mechanics of Blood Flow
Blood pressure is the force of circulating blood against the inner walls of blood vessels. The amount of pressure is determined by how much blood your heart pumps, how forcefully your heart is pumping, and the amount of resistance to blood flow in your arteries. Arteries are flexible, capable of narrowing or expanding. This isn’t the same, however, as the flexibility of a plastic hose, which responds mechanically to pressure inside it. Arteries are living tissue, and they can expand or contract due to stress or changing emotional states. Blood pressure isn’t steady, either; it normally fluctuates throughout the day. Hypertension is diagnosed as persistently high pressure in the arteries.
Blood pressure is generally expressed as two numbers. The first or top number represents the pressure when your heart contracts: the systolic pressure. The second or bottom number represents the pressure when your heart rests between beats: the diastolic pressure. A single high reading isn’t enough for a diagnosis of hypertension. Healthcare practitioners will generally take a number of readings over several different days before making a diagnosis. Normal blood pressure is considered to be <120 systolic and <80 diastolic. Prehypertension is 120-139 systolic or 80-89 diastolic. High blood pressure, stage 1, is 140-159 systolic or 90-99 diastolic. Stage 2 is >160 systolic or >100 diastolic. Pressure of >180 diastolic or >120 systolic is a hypertensive emergency. This level of hypertension can permanently damage organs, so medical help must be sought immediately.
Three types of hypertension
Before considering prevention and treatment, one has to look at the three types of hypertension that exist, since they aren’t all alike. Primary, or essential, hypertension accounts for 90-95% of all cases and doesn’t have a specific medical cause. This is the type almost all of us must pay attention to in our lifestyle choices. Secondary hypertension, on the other hand, is caused by an underlying condition, for instance kidney disease. If the underlying condition is corrected, blood pressure usually returns to normal. A third type, pregnancy-related hypertension, may occur in pregnant women who already have a predisposition to hypertension.
Primary hypertension may have no specific cause, but still there are a number of factors that put you more at risk for developing it. Most can be managed while a few cannot.
Risk factors that can be managed include:
• Obesity (a primary risk factor)
• Smoking or using tobacco in any form
• Drinking too much alcohol
• Lack of exercise
• High levels of fat and cholesterol in your blood
• Too much salt (sodium) in your diet
• Too little potassium in your diet
• Too little vitamin D in your diet
• Oral contraceptives
• Certain chronic conditions, like diabetes and sleep apnea
These risks all imply positive changes to reverse them. Before going into that area, let me finish with the medical details.
Risk factors that can’t be managed include:
• Age. The risk of hypertension increases as you age.
• Race. Hypertension is more common among African Americans.
• Genetics. High blood pressure tends to run in families.
Hypertension and atherosclerosis are intimately related. Hypertension can cause atherosclerosis, or hardening of the arteries, when the walls of the arteries try to defend themselves against high blood pressure by becoming stiffer, thicker, and narrower. On the flip side, atherosclerosis can raise blood pressure when arteries become stiff and choked by plaques, impeding blood flow.
The complications of atherosclerosis are many, and they can be very serious.
• Heart disease. Reduced blood flow to the heart can cause angina (chest pain). Heart attacks can result when coronary arteries are completely blocked. Uncontrolled hypertension is one of the major risk factors for heart disease, the leading cause of death in the US.
• Stroke. People with even prehypertension have a greatly increased risk of stroke. Atherosclerosis can cause blockage in the arteries that feed the brains as well as weakening of the smaller blood vessels of the brain.
• Enlarged heart. Narrowed arteries make it difficult for the heart to move blood through them. The heart overworks and in doing so becomes both larger and weaker. This can lead to congestive heart failure.
Among other complications, hypertension damages tiny capillaries as well as arteries. This can cause:
• Kidney disease. The kidneys are densely packed with millions of capillaries whose job it is to filter waste from the blood. Hypertension gradually destroys these capillaries, which are replaced by scar tissue.
• Vision damage. Hypertension can cause the capillaries in your eye’s retina to rupture and also damage the capillaries that supply it with blood to your retina. The results may be blurred vision and even blindness.
Doctors should advise patients with rising blood pressure to make healthy changes in their lifestyle before prescribing any medicine. Many times these changes are all that is needed to bring pressure down to a normal level. But the key is to make them yourself before symptoms arise or pressures elevate. A conscientious doctor may give you an early warning, but realistically, the responsibility lies with you, and the earlier you adopt a positive lifestyle, the greater the benefits decades from now. Last-minute intervention is the worst choice, since it usually sentences a patient to prescription drugs for the rest of his life.
Exercise, and particularly aerobic exercise, lowers hypertension as much as some medications. Exercising regularly, for a minimum of 30 minutes a day, 5 days a week, lowers pressure by an average of 5-10 mm Hg. This can allow you to lower the amount of medication you take or even do without it altogether.
Being physically active:
• Strengthens the heart so it pumps more efficiently and with less force
• Increases production of nitric oxide, a naturally occurring substance that induces arteries to dilate
• Reduces inflammation, a major cause of artery-hardening plaque
• Improves cholesterol and triglyceride levels
• Reduces stress
Remember, exercise doesn’t necessarily mean running on a treadmill or swimming laps. Anything that increases your respiration and heart rate counts, from raking leaves to going up and down stairs.
Lowering your salt intake and eating whole foods that are high in nutrients and antioxidants are seen as keys to lowering your blood pressure through diet. But you should pay specific attention, because most people, up to 80% are not salt sensitive; that is, their salt intake doesn’t immediately translate into higher blood pressure. That’s not the same as saying that our national habit of overdoing on salt is healthy, since other considerations, such as putting stress on the kidneys, come into play. There is no “blood pressure diet” that resolves hypertension specifically, as long as you aren’t gaining excess weight or eating too many fats.
The following foods are rich in inflammation-fighting antioxidants, fiber, and essential nutrients:
• Whole grains, such as oatmeal, whole wheat, and quinoa
• Colorful vegetables, like dark leafy greens, tomatoes, sweet potatoes, and carrots
• Dark-skinned fruits, including black grapes, cherries, and plums
• Lean protein, such as fish, chicken, and vegetable protein
• Nuts, seeds, and legumes
• Canola oil and extra-virgin olive oil
• Salt. Sodium (salt) causes some people to hold extra water, putting additional stress on their heart and blood vessels and causing blood pressure to rise. Watch out for processed food and restaurant food, especially fast food, which tend to be high in salt.
• Alcohol. Having more than two drinks a day raises the risk of hypertension by 1.5-2 times. The more alcohol your drink, the greater the risk.
• Caffeine. Caffeine can cause brief but dramatic increases in blood pressure.
• Sugar. There’s growing evidence that eating a diet high in sweets may lead to hypertension.
If you smoke, quit. Smoking raises your blood pressure from 5-10 mm Hg or more every time you light up. Quitting smoking reduces inflammation and greatly decreases the chances of having a heart attack and stroke.
Unmanaged stress increases blood pressure because stress elevates levels of corticosteroids, the “stress hormones.” Corticosteroids increase blood pressure, among other physiological effects.
Being overweight or obese makes hypertension worse. As your body weight increases, your blood pressure goes up, too.
The reverse also holds true: as you lose weight, your blood pressure goes down. Losing as little as 5 lbs. can reduce hypertension. The more weight you lose, the lower your blood pressure can go. In one study of over 1,200 people, those who lost 10 lbs. (4.5 kg) or more had reductions in diastolic and systolic blood pressure of, on average, 5.0 mm Hg and 7.0 mm Hg.
Get enough sleep
There’s a link between hypertension and not getting enough sleep. In a recent study, both systolic and diastolic blood pressure were higher in people who slept less than 8 hours a night. Sleep helps to regulate stress hormones and maintains the health of the nervous system. It’s possible that stress hormones that are unregulated due to lack of sleep could contribute to hypertension.
Treatment with medication
If lifestyle measures don’t lower blood pressure sufficiently, one or more medications may be prescribed.
• Thiazide diuretics dilate blood vessels and decrease fluid volume.
• Angiotensin-converting enzyme (ACE) inhibitors dilate blood vessels.
• Angiotensin II receptor blockers (ARBs), like ACE inhibitors, dilate blood vessels.
• Beta-blockers slow heart rate, decrease cardiac output, lessen the force with which the heart muscle contracts, and dilate blood vessels.
• Calcium channel blockers decrease the pumping strength of the heart, slow the heart rate, and relax blood vessels and muscles.
• Renin inhibitors cause blood vessels to dilate.
It’s a reasonable idea to self-monitor your blood pressure, keeping track of your readings in a blood pressure diary. Self-monitoring shows you if your treatment is working and how well your hypertension is being controlled. But be aware that your readings will go up and down, with daily highs and lows along with weekly variations. That means monitoring your blood pressure at various times during the day so that you can see if there are times when your pressure spikes.
Ask your healthcare practitioner when and how often you should check your blood pressure. In general, it’s the low number that is significant since it shows the pressure of a body at rest, which is the pressure your cells and organs must live with. The higher number fluctuates, usually over a short period – only if it is persistently high, along with a bad reading of the low number, should you consider yourself at risk. Also, “white coat syndrome,” which causes many people to get an abnormally high spike because of the stress of visiting a doctor, can extend to home monitoring. Worrying about your blood pressure tends to make hypertension worse, so if self-monitoring is an extension of worry, reconsider how good it is for you.
There is no escaping that high blood pressure, like every lifestyle disorder, poses two choices that many people find unpalatable: live with positive habits or resign yourself to taking medication as you grow older. We live at a time when prevention has proven itself over and over, while the general population becomes more sedentary and obese. In the end, all lifestyle options are a matter of personal choice. Moving in the right direction doesn’t need to be drastic if you start early enough. Stay in your comfort zone while reassuring yourself that the zone can expand until you reach your ideal goal.