The Essence of Normal Blood Pressure and your Heart

What is high blood pressure, known medically as hypertension; and why is it important to keep it in a normal range?  Blood pressure reading reflects how hard your heart is working, and in what condition your arteries are. During strenuous activities, the heart pumps considerably more blood to meet the body’s increased demand for oxygen. As the blood pushes into the arteries with each heartbeat, it forces the arterial wall to expand, much like an elastic band stretches to accommodate your body. When the blood flow ebbs, the vessel returns to the original shape. The less flexible the vessels are the harder it is to propel blood through them, and the higher your pressure reading. Vessels that are narrowed, tightened or inflexible as a result of plaque buildup over the years have a higher pressure at any level of flow.

According to a new update from the American Heart Association and the American College of Cardiology, anyone with a reading of 130/80 mm Hg or above is considered to have high blood pressure. The guidelines are based on growing evidence showing that lower blood pressure values are associated with fewer heart attacks and strokes. It has also been observed that people with a high blood pressure who smoke; have elevated blood sugar levels, and high cholesterol, have accelerated damage to their arteries, kidneys, and heart. The top number or systolic pressure reflects the amount of pressure during the heart’s pumping phase or systole. As the heart contracts pressure in the artery temporarily increases as blood is forced through them. The bottom or diastolic pressure represents the pressure during the resting phase between heartbeats.

Basic lifestyle changes like eating more fruit and vegetables, exercising more, and practicing stress reduction techniques should always be the foundation of treatment and can preclude the need to take medication for maintaining normal blood pressure. The high number of the blood pressure reading especially the systolic means your heart is working harder to pump blood through your body. This extra work can lead to thickening of your heart muscle and potential heart, kidney, and brain damage. The pounding of the blood against the arteries can cause an accumulation of cholesterol deposits, which can diminish blood flow, and potentially set you up for a heart attack, stroke or kidney failure.

Besides the lifestyle changes which is always recommended for people with high blood pressure, treatment with a single medication or a combination is often dependent on the level of hypertension. The question may be asked what happens to the blood pressure during episodes of acute dramatic sudden stress like running to catch a bus, or being involved in an acutely stressful situation? The body takes dramatic adjustments in blood pressure within seconds to meet sudden demands, and these changes are directed by complex interactions between the central nervous system, hormones, and substances produced in the blood vessels. In spite of the natural fluctuations, your body keeps your blood pressure relatively stable most of the time. Just as a thermostat adjusts your furnace or air conditioner to keep your house at a comfortable temperature, pressure sensitive nerve cells in the cardiovascular system called baroceptors, continuously monitor your blood pressure. When the blood pressure gets too high (such as during stress) or too low (when you are dehydrated) baroceptors relay information to your anatomic nervous system that sets off a chain of events designed to restore blood pressure to normal levels. At times the system fails, leading to a problem known as orthostatic hypotension, particularly in the elderly (when the BP suddenly drops). Often when this occurs, assuming a sitting position gradually restores the normal pressure. The high blood pressure discussed so far is called Essential Hypertension;  90 to 95% of people with high blood pressure have this type. It is also called primary hypertension; and it is not caused by another medical condition, medication or substance. A variety of factors contribute to the development of hypertension, and many of them are unknown. This may explain why people who are salt-sensitive, control their blood pressure with a low sodium diet alone; while others find sodium intake has little or no influence on their blood pressure. The other type of hypertension is secondary hypertension; and this includes hyperaldosteronism, hyperthyroidism, renal artery stenosis, pheochromocytoma, Cushing’s syndrome, coarctation of the aorta, sleep apnea etc.