The Ups and Downs of Blood Pressure

Dr. Phil Maffetone

The force of blood pushing against the walls of the arteries as the heart pumps blood creates pressure. This blood pressure is always changing. It lowers during sleep and relaxation, and rises when you’re awake, stressed and excited. It even changes slightly from minute to minute to compensate with the body’s need for increased or decreased blood supply. During the course of a 24-hour cycle—the circadian rhythm—blood pressure is usually lowest in the early morning hours, rises to reach a peak in mid- to late afternoon, then gradually lowers.

Normally, the systolic blood pressure range can vary 10 to 15 mm Hg, while the diastolic can vary from five to 10.

In those with hypertension, because the blood vessels are not healthy, wider ranges of blood pressure reading most often occur. This includes the condition called "white coat hypertension," where the stress of a visit to the doctor's office causes an elevation in blood pressure. This can result in a normal blood pressure of, say, 120/80, to jump to 136/90, leading your doctor to claim you have “prehypertension.” Thirty-five percent or more of people with hypertension may have this “white coat” variety.

Hypertension

One factor associated with cardiovascular disease is high-blood pressure, or hypertension. It’s not only a risk factor for heart disease, but overall mortality. Hypertension is generally defined as blood pressures above about 140/90 (the first number is the systolic pressure, and the second diastolic as measured in millimeters of mercury or mm Hg).

Intense marketing of hypertension drugs, corresponding with newer definitions of hypertension, have resulted in more people being medicated, and even those with normal blood pressure being told they are in a pre-hypertensive state. Indeed, doctors are now reading in medical journals that cardiovascular risk begins with blood pressures as low as 115/75, and that the blood pressure classification of “prehypertension” is a systolic pressure between 120–139 and diastolic between 80–89 mm Hg.

To make matters worse, most patients are prescribed medication for hypertension without seeking the cause of the problem. And, most patients are not given appropriate diet and lifestyle guidelines that may reduce their blood pressure to the point where medication may no longer be needed.

Among the problems that may contribute to hypertension is carbohydrate intolerance due to its influence of raising insulin levels. During the Two-Week Test it was recommended that, if your blood pressure is high, have it evaluated before, during and after the Test. That’s because for many people, significantly reducing refined carbohydrates and sugars, which reduces insulin levels, will lower blood pressure — often dramatically. As a result, if you’re taking medication to control blood pressure, your doctor may need to reduce, or even eliminate it.

The vast majority of hypertensive patients I initially saw in practice were able to reduce their blood pressure significantly just by strictly avoiding refined carbohydrates and sugars, especially when easy aerobic exercise was implemented. Most of these patients were able to eliminate their medication. Other important factors include balancing fats, various nutrients that can be obtained from a healthy diet, and controlling stress.

Poor aerobic conditioning can also contribute to hypertension. Recall that those who are inactive have a significant amount of blood vessels shut down (these are the vessels in the aerobic muscle fibers). Aerobic exercise is an important factor in both prevention and treatment of hypertension. Even one easy aerobic workout can reduce blood pressure for up to 24 hours. Anaerobic exercise may not be nearly as effective and could even aggravate high blood pressure. It’s important to discuss your particular exercise needs with a healthcare professional — especially one who is aware of the potential benefits of food, nutrition and exercise.

Other dietary factors that can prevent or help hypertension include eating sufficient amounts of vegetables and fruits. When certain nutrients are low, such as calcium and vitamins A and C, the blood pressure may elevate. Basically, by increasing overall fitness and health, blood pressure can be normalized in the majority of people.

It’s also important to look at the whole person, as hypertension often means other problems exist. For example, kidney problems and narrowed or “clogged” arteries are commonly associated with hypertension.

Hypotension—Low Blood Pressure

Hypotension is abnormal and unhealthy. It results in less blood getting to the heart muscle, brain, intestine and virtually all the body’s cells. Low blood pressure is considered below 90/60 mm Hg, but many individuals have signs and symptoms when systolic pressure falls under 100.

Hypotension can cause muscle weakness, sleepiness, fatigue, and dizziness, and even fainting. In severe cases, low-blood pressure can cause blurry vision, confusion and be life-threatening.

Hypotension could be caused by various drugs, including alcohol, antidepressants and anti-anxiety medications, painkillers, and diuretics. In addition, dehydration, diabetes, certain heart problems like arrhythmias, and fainting can cause low blood pressure.

A specific type of low blood pressure is called orthostatic hypotension. It occurs following a sudden change in body position, most often from lying down to standing, although sometimes sitting up after lying down, or just bending over to pick something off the floor while standing can trigger it. Symptoms include dizziness and lightheadedness that usually lasts only a few seconds or minutes. Technically, orthostatic hypotension occurs with a pressure drop of 20 mm Hg or more, but many patients get symptoms with much less of a drop in blood pressure. (Postural hypotension can also occur after eating and is called postprandial orthostatic hypotension.)

An imbalance in the nervous system (autonomic dysfunction) and poor adrenal function can also contribute to hypotension, especially the orthostatic type. Treatment involves finding the cause and eliminating it.

Following exercise of various intensity and duration, there is typically a normal drop in blood pressure into the lower ranges of normal. This post-exercise hypotension is defined as a pressure that is lower than the pre-exercise value, and can persists for minutes or hours after an exercise session. This phenomenon is one of the reasons exercise can help improve the health of those with cardiovascular disease.

Sodium and Blood Pressure

A common notion about high blood pressure is that sodium causes it. In some people with existing high blood pressure, too much dietary sodium—above an individual level—can magnify the problem. And that amount is very individual. About 30 to 40 percent of those with hypertension are sodium-sensitive. For these individuals, even moderate amounts of sodium can increase their blood pressure further. Obviously, these patients should regulate their sodium intake, which is most easily done by avoiding packaged and processed foods and maintaining a diet high in fresh fruits and vegetables, and other natural items. But salt modification for those who have normal blood pressure is not necessary, as sodium will not raise blood pressure in healthy individuals.

Sodium is a necessary nutrient, essential for good health. An average healthy man of 150 pounds has about 9,000 milligrams of sodium in his body. One-third of this is contained in the bones and most of the remaining two-thirds surrounds the cells throughout the rest of the body, where sodium is a major player in their regulation. Balanced with potassium, sodium acts as an “electrochemical pump” in accomplishing this remarkable feat. Sodium also helps regulate the acid/alkaline balance, water balance, the heartbeat and other muscle contractions, sugar metabolism and even blood-pressure itself.

In a study on salt and the heart, Jan A. Staessen, M.D., Ph.D., and colleagues from the University of Leuven in Belgium reported in the May 4, 2011 issue of the Journal of the American Medical Association that higher sodium intakes did not translate into a greater risk of hypertension or cardiovascular disease. In fact, their study showed that those with lower sodium had an increased risk of cardiovascular mortality. They studied 3,681 men and women, and after about eight years there were 50 deaths in the low sodium group, and 10 deaths in the high sodium group. The authors state that "Our current findings refute the estimates of computer models of lives saved and health care costs reduced with lower salt intake," and that they do not support the popular recommendations of a generalized and indiscriminate reduction of salt intake. These so-called “recommendations” come from the American Heart Association and the U.S. government.

Blood pressure tends to rise with age because in most individuals, overall health declines with passing decades. By remaining healthy and fit, you can maintain normal pressures.
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