Causes of Hypertension
Hypertension is divided into two categories based on whether or not there is a clear cause that can be identified. In the case of essential hypertension (also called “primary” hypertension), the precise cause is not known, but the person may have common risk factors that are normally associated with developing high blood pressure. With secondary hypertension, on the other hand, the direct cause may be identified and directly addressed.
Obesity is one of the most common risk factors for essential hypertension, accounting for approximately two-thirds of patients with high blood pressure. Scientists have confirmed this link through clinical studies and identified several elements of physiology that play roles in contributing to the development of hypertension. For example, it has been shown that obesity may trigger signals in the nervous system that tell the kidneys to produce more renin, which (as mentioned above) increases blood pressure. There is also a correlation between obesity and insulin resistance. Insulin is the hormone best known for helping to regulate blood sugar levels, however it also been shown to have vasodilation, or blood vessel-widening, properties. If the body develops a resistance to insulin, hypertension may be a byproduct of the resulting blood vessel constriction.
High sodium (salt) level in the blood is also commonly linked to the development of hypertension. If there is excessive sodium in the blood flowing through the blood vessels, the surrounding tissues will try to balance this by releasing water. The extra water volume will create additional pressure against the blood vessel walls, which is the hallmark of hypertension. Dietary deficiency of vitamin D has also been associated with development of hypertension and other cardiovascular disease. Researchers have found that vitamin D inhibits secretion and activity of renin from the kidneys, which may explain the incidence of high blood pressure in those with insufficient vitamin D intake.
There also appears to correlation with hypertension and age, though it is not clear one. One possibility is that the blood vessels become less pliant and flexible as we age. Another is that the kidneys may become less effective at eliminating sodium as we age, even if high dietary sodium was never a factor during younger years. Genetics may also play a role in predisposing a person to high blood pressure, though it is also likely a complicated contributor. More than 50 genes have been examined for possible direct roles in development of hypertension. Although no one gene has been unequivocally linked to the condition, familial analysis and studies of twins suggest that there is a reasonable genetic component.
One common cause of secondary hypertension is medication, including certain over the counter pain relievers (such as ibuprofen), nasal sprays, cough medicines, and birth control pills. If a patient stops taking blood pressure medications, this can also cause a significant spike in blood pressure, returning them to a hypertensive state. Some foods, such as licorice, can also naturally increase blood pressure if consumed in excessive amounts.
About half of patients with sleep apnea also exhibit hypertension, in part because their blood pressure does not drop while sleeping. (Please see our article on Sleep Disorders for more information on sleep apnea.) The mechanism is not completely understood, but treatment of the sleep apnea generally returns the blood pressure to normal.
There are several kidney disorders that have also been directly linked with hypertension. As mentioned before, there is significant interplay between the kidneys and blood pressure, through control of salt levels, secretion of renin, and other physiological signaling. Any disease associated with the kidneys or the arteries supplying blood t o the kidneys can result in hypertension. Glomerulonephritis, an inflammation of the blood vessels in the kidney, for example, may cause hypertension as a secondary effect. Polycystic kidney disease (PKD), in which multiple cysts develop in the kidneys, can also disrupt kidney function and lead to hypertension.
Hypertension may also result from hormonal imbalance. In the case of Conn’s Syndrome, too much of the adrenal hormone aldosterone is produced, which causes the kidneys to retain salt. This causes water to be retained as the body tries to balance the salt levels, which in turn increases the blood pressure. Cushing’s syndrome is a disorder in which the adrenal glands produce too much of the hormone cortisol, a “stress hormone” that increases both blood sugar and blood pressure.
Approximately 10% of pregnant women develop gestational hypertension. Although it usually does not indicate any other overarching health problems, it can put the mother and baby at significant risk, so it is critically important to monitor the blood pressure throughout pregnancy.
Conventional Treatment of Hypertension
Essential (primary) hypertension cannot be cured, but it can be managed to avoid future complications. If there are no symptoms beyond the high blood pressure, medications are rarely prescribed because they may have side effects. Instead, those with high blood pressure are encouraged to make healthier life choices to improve their overall state of vascular health and reduce their risks of stroke, heart attack, and other common complications of hypertension.
Because of the prevalence of hypertension related to obesity, most patients are recommended dietary and lifestyle changes that will help them to lose excess weight. Even losing as few as 10 pounds can significantly reduce blood pressure. Patients are advised to lower salt and fat intake, avoid drinking and smoking, and begin regularly exercising. Self-monitoring of blood pressure is also a part of conventional hypertension treatments, as it can help improve motivation and help cultivate a sense of progress.
In more extreme cases, blood pressure medications (antihypertensives) may be prescribed to help control blood pressure. There are numerous blood pressure medications available, all with different mechanisms and potential side effects. The oldest and most studied of these medications are diuretics, which increase the excretion of salt and water from the kidneys. The most common side effect of diuretics is frequent urination, though some patients are at risk for losing potassium, as well.
Beta-blockers are a class of antihypertensives that lower the blood pressure by reducing the intensity of the heart beat, thus putting less pressure on the blood vessels. With this treatment, there is a risk of lowering the heart rate too much, causing the complications of low blood pressure (confusion, depression, heart failure).
Calcium channel blockers both decrease the strength of heart contractions (like beta-blockers) and help dilate the arteries to facilitate blood flow and lower blood pressure. Again, there is risk for reducing the heart rate too extensively and causing heart failure.
There are also two types of drugs that affect the protein angiotensin, which normally contributes to the constriction of the blood vessels. ACE (angiotensin-converting enzyme) inhibitors and ARBs (angiotensin-receptor blockers) both disrupt the normal activity of angiotensin and promote dilation of the arteries. By widening the blood vessels, these drugs make it easier for the heart to pump blood through the body.
Patients Medical's Treatment of Hypertension
Because the causes of hypertension can be many layered, your treatment program at Patients Medical will be both intensive and thorough. During an initial meeting, our physicians will help you identify the risk factors that may be contributing to your hypertension, paying particular attention to diet, lifestyle, and family history. If you have a form of secondary hypertension, where the cause is by a known and treatable condition, this will obviously be factored into your treatment program. Each hypertension treatment is designed specifically for the individual patient, considering their current weight, health concerns, and personal health goals.
The cornerstone of healthy blood pressure is a healthy lifestyle. Our doctors can outline a modified diet for you, rich in vegetables, fruits, and whole grains to promote healthiness of the heart. Antioxidant-rich foods have also been shown to play a preventative role in the development of vascular disease. It is recommended that a wide variety of antioxidant-rich foods be worked into the diet, so we will provide a comprehensive list to help you plan your meals. Blueberries, red beans, artichokes, apples, pecans, plums, and even potatoes are some of the most antioxidant rich foods. There are also many spices that have hypertension reducing effects, such as tarragon and basil.
We will also recommend that you reduce sugar and salt in your diet, as they are some of the most common dietary contributors to hypertension. Foods rich in potassium, magnesium, and calcium can improve your blood pressure in addition to your overall health. Depending on the case, vitamin and mineral supplements may also be prescribed to help rebalance the body’s chemistry. Arginine Plus™ with Magnesium, for example, combines minerals and amino acids known to promote healthy metabolism, support muscle activity, and maintain normal blood pressure.
We can also prescribe nutritional supplements to reduce your hypertension, such as Vasotensin®, which contain proteins from the bonito fish that have found to have natural ACE inhibitor activity. Synthetic ACE inhibitors are commonly prescribed in conventional hypertension treatments, as they disrupt the vasoconstrictive properties of another protein called angiotensin. Vasotensin® can offer this same effect from a natural source and this supplement has an excellent safety profile.
In addition to dietary modifications, we will recommend an exercise program suited to your current medical condition that will help you lose weight, a key factor in lowering blood pressure. Blood pressure naturally increases during exercise to bring oxygen and nutrients to our muscles and tissues, so care must be taken to exercise gently and not overexert the cardiovascular system. Walking, yoga, and other low impact exercises will be initially recommended to help you burn calories, lose weight, and gradually improve your circulatory health. Exercise is also an excellent way to reduce stress, another factor that contributes to high blood pressure. Massage, meditation, and other relaxation therapies may also be suggested to help alleviate stress. (Please see our article on Stress for more information about our stress therapy programs.)
Next Steps:
Poor health can significantly affect your life. Improve your life by changing to good health. Call our patient coordinator at 1-212-679-9667 or click on Request an Appointment to schedule an appointment with one of our doctors for evaluation and testing.
We are located at: Patients Medical PC, 800 Second Avenue, Suite 900 (Between 42nd & 43rd Street), Manhattan, NYC, New York, NY 10017.
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Article Last Updated: 08/24/2009