Blood Pressure Management

Risk Factors for High Blood Pressure

Advancing age, gender, family history and genetic predisposition all contribute to the development of high blood pressure. However, they’re considered non-modifiable risk factors, meaning that it’s not possible to reduce the risk that these factors pose by taking preventive action. Modifiable risk factors, on the other hand, also contribute significantly to the development of high blood pressure but can be addressed through preventive actions. Modifiable risk factors for hypertension include:

• High sodium intake - According to emerging hypotheses, excess sodium appears to alter the balance between excitatory and inhibitory adrenergic receptors in such a way that favors vasoconstriction, leading to increased blood pressure (Gavras 2012). A 2011 study found that individuals with hypertension consume significantly more sodium each day than those without high blood pressure (Shi 2011). Overindulging with salt also increases the risk for stroke, kidney disease, and cardiovascular disease (He 2010; Demarin 2010). In order to avoid the hypertensive effects of sodium, intake should be limited to 2.4 grams of sodium, or 6 grams of sodium chloride (table salt) daily (Chobanian 2003).
  
  
• Low potassium intake - Adequate potassium intake helps balance the hypertensive effects of sodium. Diets containing excess sodium require ample amounts of potassium-rich foods to help mitigate the hypertensive consequences of modern sodium overindulgence. The suggested potassium intake for adults is 4.7 grams per day, but most Americans consume far less.
  
  
• Obesity and Insulin Resistance – Body weight gain accounts for as much as 75% of the risk for high blood pressure (Marion 2004). Nearly 70% of Americans are overweight. As body fat mass increases, blood volume increases as well, which contributes to increased blood pressure. Insulin resistance, which often occurs in tandem with obesity, contributes to vascular resistance and increased blood pressure (Reisin 2009).
  
  
• Stress – Stressful situations cause the release of hypertensive (blood pressure raising) hormones, such as epinephrine. As chronic stress causes the continual release of hypertensive hormones, the sustained elevations in blood pressure become dangerous. A study following government employees who participated in disaster relief efforts in the Niigata Prefecture of Japan after the 2004 earthquake found that those with the most stressful workloads were much more likely to develop high blood pressure. Individuals under the greatest stress were also more likely to gain weight and have high cholesterol levels (Azuma 2010).

• Sedentary lifestyle, smoking, and too much alcohol can all increase the risk for high blood pressure. Light alcohol consumption does confer benefits for cardiovascular health, while heavy alcohol ingestion increases the risk of hypertension. Therefore, intake should be limited to two drinks daily for men and one drink daily for women (Chobanian 2003).

Though conventional physicians usually consider the aforementioned risk factors, mainstream medicine has overlooked two important contributors that may play a significant role in blood pressure regulation – vitamin K and vitamin D.

• Low Vitamin D intake – Insufficient intakes of this hormone-like vitamin are implicated in the pathology of high blood pressure along with numerous other diseases. Studies suggest that vitamin D might target many of the factors that contribute to hypertension including suppressing renin, a hypertensive enzyme, and protecting kidney function (Pillz 2010). In a review of 10 randomized controlled trials, use of vitamin D supplementation was shown to mildly reduce blood pressure. Moreover, individuals with higher blood levels of vitamin D were at less risk of developing cardiovascular disease (Pillz 2010). Life Extension suggests that all individuals maintain a blood 25-hydroxyvitamin D level of 50 – 80 ng/ml.

• Low Vitamin K intake - Vitamin K is required to maintain soft and pliable arterial walls. Inadequate vitamin K intake can result in an accumulation of calcium in the arterial wall, leading to hardening of the arteries and increased peripheral resistance (Schurgers 2007). Ensuring adequate vitamin K intake allows for proper allocation of calcium into the bones to maintain skeletal integrity and away from the arterial wall, helping prevent the arterial “stiffness” that robs so many aging individuals of proper circulation.

Pharmaceutical Therapies for Hypertension

Conventional management of hypertension begins with lifestyle modification, followed by the possible addition of one or more antihypertensive drug therapies to achieve a target blood pressure goal of less that 140/90 mm Hg (< 130/80 mm Hg for persons with diabetes or renal disease). As described earlier, studies show that blood pressure over 115/75 mmHg can increase risk of vascular disease. However, it is also important to consider that overly aggressive blood pressure lowering in aging individuals with pre-existing, long-standing hypertension or other cardiovascular disease may be dangerous.

Thus, a blood pressure reduction regimen must be accompanied by close supervision and careful monitoring of blood pressure throughout the day. A diligent plan encompassing regular at-home blood pressure monitoring and regular healthcare practitioner-patient interaction will ensure optimal risk reduction and patient safety.

Antihypertensive drugs lower blood pressure by attenuating one or more of the blood pressure regulating mechanisms. Major “classes” of antihypertensive drugs are variably defined, but the most widely prescribed can be grouped into 3 categories based on their activites.

Diuretics

Reduction of blood volume is the first target of conventional antihypertensive therapies. Diuretics (thiazide diuretics, loop diuretics, potassium-sparing diuretics) are the the most commonly prescribed drugs in this category. Diuretics exert effects upon the kidneys to increase the excretion of water. This drop in blood volume results in a drop in pressure.

Adverse effects of thiazide diuretics include sexual dysfunction, glucose intolerance, gout, low potassium level (hypokalemia), and low sodium level (hyponatremia). Conventional doctors often overlook the depletion of vital magnesium that can be caused by diuretics. Many patients do better by starting with the angiotensin II receptor blockers described later in this chapter. Those who require diuretic drugs should supplement with plenty of magnesium and potassium if dietary intake is low (dietary intake of magnesium is usually too low even for those who don’t take diuretic drugs).

Cardioinhibitory drugs

Cardioinhibitory drugs decrease the rate and force with which the heart pumps, reducing cardiac output and lowering blood pressure.

Beta blockers lower heart rate and blood pressure by blocking the beta adrenoceptors. Normally, these adrenoceptors sense the hormones epinephrine (adrenaline) and norepinephrine in the blood and respond by increasing heart rate and constricting blood vessels outside the heart. Beta blockers disrupt this interaction.

Beta blockers are contraindicated in individuals with COPD (chronic obstructive pulmonary disease) and asthma. Side effects include a worsening of blood glucose control (in diabetics), elevated triglycerides, and lower high-density lipoprotein (HDL—sometimes called the “good” cholesterol) levels. These drugs may exacerbate depressive symptoms, cause erectile dysfunction, and are associated with sleep disturbances, fatigue and lethargy.

A second group of drugs, calcium channel blockers, specifically bind to and block the channels (cellular pores) that allow calcium to flow into cardiac muscle cells. Since muscle fibers require calcium for contraction, reducing the availability of calcium in cardiac muscle lowers the force at which the heart contracts, lowering blood pressure. Additionally, certain calcium channel blockers, which are less specific toward calcium channels in the heart, also have vasodilating properties.

Side effects commonly associated with calcium channel blockers include flushing of the face and neck, headaches, edema (swelling) usually in the ankles and feet, dizziness, fatigue, and skin rash.

Vasodilators

Vasodilators increase the diameter of vessels, lowering their resistance and the pressure required to move blood through them. There are several types with differing mechanisms. Angiotensin-converting enzyme (ACE) inhibitors stop the activity of ACE, the enzyme which catalyzes the final step in the synthesis of the hypertensive hormone angiotensin II. By lowering levels of angiotensin II, ACE inhibitors promote the dilation of blood vessels, increasing the excretion of water and sodium from the kidneys, thereby lowering blood volume. Frequent side effects of ACE inhibitor use include dizziness, fatigue, weakness, headaches and persistent dry cough.

Renin inhibitors, another group of vasodilator, also reduce angiotensin II levels at the first step of its synthesis. This class of drug is associated with several side effects, which include diarrhea, dizziness, flu-like symptoms, fatigue, and cough.

Angiotensin receptor blockers (ARB) have similar effects to ACE inhibitors. Instead of reducing the levels of angiotensin II, however, they reduce its bioactivity, preventing it from interacting with receptors on the surface of cells and signaling hypertensive effects.

In addition to efficiently lowering blood pressure (Heran 2008), a comprehensive review of published studies, which examined data for nearly 150,000 subjects, revealed that use of an angiotensin receptor blocker was associated with a 10% reduction in the likelihood of having a stroke, suffering from heart failure, or developing diabetes (Bangalore 2011).

Angiotensin receptor blockers also convey some surprising additional benefits. Studies show that suppressing the signaling of angiotensin receptors may blunt oxidative stress and encourage the activation of genes associated with enhanced longevity. Amazingly, animals genetically engineered not to express the primary angiotensin receptor were shown to live 28% longer than normal animals (Benigni 2009). Moreover, these animals also have a greater number of mitochondria, the cellular components that provide the energy our bodies need to function with youthful vigor (Cassis 2010). Other data indicates that angiotensin receptor blockers may help modulate the immune system in ways that discourage autoimmunity, suppress inflammation, and slow the progression of cardiovascular disease independently of their effects on blood pressure (Stegbauer 2011).

Angiotensin receptor blockers may cause dizziness, headache, or elevated blood levels of potassium (hyperkalemia). However, most individuals do not experience these effects.

For many of those with hypertension, taking an individualized daily dose of an angiotensin receptor blocker can keep blood pressure readings in optimal ranges over a 24 hour period.

Alpha blockers prevent the binding of norepinephrine to alpha adrenoceptors, which are located on vascular smooth muscle cells within blood vessel walls. They function much like the beta blockers do in the heart, preventing the contraction of blood vessels in response to stress hormones. This class of medication can sometimes cause dizziness, lightheadedness, or fainting upon arising from a sitting or lying position.

Lethal Misconception about Anti-Hypertensive Drugs

A properly functioning heart is of little consequence without the means to maintain a predictable pressure throughout the circulatory system. A dangerous assumption made by doctors is that once a day dosing with an anti-hypertensive drug will keep a patient’s blood pressure under control over an entire 24-hour period. The reality is that these drugs will wear off in many patients within 12 to 18 hours, leaving the body vulnerable to dangerous daily blood pressure spikes. Few physicians understand that it is during periods of the day when blood pressure spikes above 115/75 that damage is inflicted. Therefore, keeping blood pressure suppressed for even 18 hours leaves patients exposed to the damaging effects of hypertension for 6 hours every day.

The best way to effectively monitor blood pressure is with an at-home blood pressure monitor. If one takes a 50 mg dose of low-cost losartan in the morning, and their blood pressure exceeds 115/75 at any time of the day thereafter, they should consult their physician about taking a second dose of losartan in the evening to ensure all-day blood pressure control. Those who take Benicar® usually only need once-a-day dosing of 10 to 20 mg.

It does not matter what drug or natural therapy one employs to lower their blood pressure. The objective is to use at-home blood pressure devices to achieve blood pressure readings no higher than 115/75 throughout a 24 hour period.

Dietary & Lifestyle Approaches to Managing Blood Pressure

Dietary modifications aim to balance macro- and micronutrient intake to favorably influence the body’s inherent blood pressure regulating systems.

Weight management, increased physical activity, limitation of alcohol consumption, and dietary modification (particularly the reduction of dietary sodium) are amongst the best studied, and most effective lifestyle changes for blood pressure management. A Body Mass Index (BMI) between 18.5 and 24.9 carries the lowest risk of hypertension. Reductions of systolic blood pressure by 5-20 mmHg per 10 kg of weight loss have been observed in several studies (The Trials of Hypertension Prevention Collaborative Research Group 1997; He 2000). Regular exercise has been associated with average reductions in blood pressure of 3.2 mmHg (systolic) and 3.5 mmHg (diastolic) in thousands of patients across many studies (Cornelissen 2005; Kelley 2000; Xin 2001). Limitation of alcohol consumption (≤ 2 drinks per day for men, less than this for women) can further reduce systolic blood pressure by 2-4 mmHg (Xin 2001).

A sodium restricted diet (< 1.5 grams/day) can significantly reduce blood pressure. The DASH (Dietary Approaches to Stop Hypertension) eating plan has been shown to lower systolic blood pressure by 8-14 mmHg, and is included among suggested dietary guidelines (Sacks 2001; Svetkey 1999). The first DASH eating plan focused on fruits, vegetables, whole grains, was especially high in fiber (31 grams/day) and potassium (4.7 grams/day), and low in animal products. Ironically, the original DASH was not a low sodium diet (allowing up to 3 grams/day), but nonetheless had blood pressure lowering effects (Appel 1997).

Fiber. How dietary fiber (both soluble and insoluble) reduces blood pressure is poorly understood. Possible mechanisms include a reduction of the glycemic index of foods and the attenuation of insulin response (insulin plays a role in blood pressure regulation). Soluble fibers may also increase mineral absorption (such as calcium, magnesium, and potassium) by several mechanisms (Greger 1999). A comprehensive review of 24 randomized, controlled clinical trials examined the effects of fiber in people with both normal and high blood pressure. They demonstrated modest reductions in systolic (1.13mmHg) and diastolic (1.26 mmHg) blood pressure at an average dose of 11.5 g fiber/day (Streppel 2005). Another review found an average reduction in both systolic and diastolic blood pressure in trials conducted among patients with hypertension (systolic 5.95 mmHg and diastolic 4.20 mmHg) and in trials with a duration of intervention ≥ 8 weeks (systolic - 3.12 mmHg and diastolic 2.57 mmHg) (Whelton 2005).

Protein. Results from a comprehensive review of hypertension studies indicate an association between low dietary protein intake and elevated blood pressure (Myers 2007). A recent review of 46 studies demonstrated the effects of plant protein on reductions in blood pressure (up to a 1.4 mmHg reduction in systolic blood pressure and a 1 mmHg reduction in diastolic blood pressure for every 11 g of plant protein consumed per day). The blood pressure lowering effect was stronger in both middle-aged and hypertensive individuals, as well as those with a high initial BMI (Altorf 2010). The mechanism for the blood pressure lowering effect of protein is unclear. It may increase sodium (and water) excretion from the kidneys, increase blood concentrations of arginine (the precursor to nitric oxide), or improve insulin sensitivity (especially if it replaces carbohydrates in the diet) (Myers 2007).

Caloric restriction (CR) is the chronic reduction of dietary calories (typically 30%, but sometimes up to 50% in some protocols), without malnutrition (Lane 1998). Restriction in energy intake slows down the body’s growth processes, causing a focus on protective repair mechanisms. The overall effect is an improvement in several measures of health.

Observational studies have tracked the effects of calorie restriction on lean, healthy individuals, and have demonstrated that moderate calorie restriction (22-30% decreases in caloric intake from normal levels) improves cardiac function, reduces markers of inflammation and risk factors for cardiovascular disease (LDL-C, triglycerides, blood pressure) (Walford 2002; Fontana 2004; Fontana 2006; Meyer 2006). Reductions of systolic blood pressure (5-10 mmHg), and diastolic blood pressure (4-6 mmHg) have been observed in studies of individuals with normal and high blood pressure that adopted a caloric-restricted regimen (Fontana 2007; Lefevre 2009; Riordan 2008;Bloomer 2010).