Hypertension (high blood pressure)

Hypertension, most commonly referred to as ‘high blood pressure’, is a medical condition in which the blood pressure is chronically elevated. Blood pressure is measured with an instrument called a sphygmomanometer. This detects the two points where internal pressure in the arm is equal to pressure in the instrument’s cuff. These are the ‘systolic’ (heart pumping) pressure and the ‘diastolic’ (heart relaxing) pressures measured in millimetres of mercury (early pressure gauges resembled mercury barometers). The blood pressure is expressed as diastolic value over systolic value, e.g., 70/120. Small battery-powered sphygmomanometers for home use are inexpensive and widely available, and are worthwhile for the early warnings of problems they can provide.

An individual is considered hypertensive if his or her resting blood pressure exceeds 90/140, i.e., a diastolic blood pressure consistently over 90 mmHg and a systolic blood pressure consistently over 140 mmHg. This includes about 25% of the adult population in many Western countries.

High blood pressure is generally classified as either 'essential' (primary) or 'secondary' hypertension, but this is a fairly meaningless distinction. Essential hypertension simply means that no specific medical cause can be identified (risk factors are smoking, drugs - both pharmaceutical and recreational, family history, obesity, alcohol, lack of exercise and diet), while secondary hypertension indicates that the high blood pressure is a result of another identifiable condition such as kidney disease, endocrine disease or narrowing of the aorta.

Hypertension usually does not cause noticeable symptoms in itself, but if the blood pressure remains elevated for long periods, this can lead to progressive damage to various organs in the body. Over several years, hypertension can lead to damage to the heart and blood vessels, making it more likely that the individual will go on to develop a stroke or heart attack. Occasionally, especially when blood pressure is extremely high, an individual may experience headaches, dizziness, or alterations in vision.

Persistent hypertension is one of the major risk factors for strokes, heart attacks, heart failure and arterial aneurysm, and is a leading cause of chronic renal failure. Even moderate elevation of arterial blood pressure leads to shortened life expectancy, particularly when diabetes is also present.

A blood pressure in the range 120/80 mmHg to 139/89 mmHg is commonly defined as 'prehypertension' meaning that it is an indicator for a high risk of developing hypertension. Although no specific medical cause can be determined in essential hypertension, the most common form, several factors may contribute to it, including salt sensitivity, renin homeostasis, insulin resistance, genetics and ageing. In people with diagnosed diabetes mellitus or kidney disease, studies have shown that blood pressure over 130/80 mmHg should be considered high and warrants further treatment.

Treatment of hypertension

Lifestyle changes

Unless the hypertension is severe or even life-threatening, a doctor will normally suggest lifestyle changes designed to reduce risk:

Lose weight if you are overweight or obese

Losing even relatively small amounts of excess weight can make a big difference. Blood pressure can fall by up to 2.5/1.5 mmHg (systolic/diastolic) for each excess kilogram of weight reduction.

Increase your level of regular physical activity

The heart is not the only blood-pumping muscle. The leg muscles in particular contribute to blood and plasma movement, and it is essential to get in some regular physical activity to assist the heart. Maintaining or increasing muscle mass will also increase calorie consumption when at rest. Ideally, aim to get at least 30 minutes of physical exercise on most days of the week. A regular brisk walk, going to the local swimming pool, taking a daily bike ride are all good. Even some intensive gardening can provide all the activity you need. At the very least, just walking up and down the stairs a dozen or so times will be helpful. Regular physical activity can lower blood pressure substantially, by in addition to giving other health benefits. If you previously did little physical activity, and change to doing regular physical activity five times a week, it can reduce systolic blood pressure by 2-10 mmHg.

Reduce salt intake (or not!)

For about 30% of hypertension sufferers, a high salt intake can be a factor in their condition. For the rest, and for the general population, there is no proven connection between salt uptake and increased blood pressure. For this reason the advice to 'cut out the salt' that is so glibly handed out by governments and medical practitioners is actually useless and possibly damaging for about 90%+ of the population. Salt, and the minerals that come with unrefined (sea) salt are actually essential components of our diet, and attempting to eliminate salt from the diet can be medically dangerous. Probably the only way to discover whether you are one of the small minority of people who are salt-sensitive for hypertension is to purchase a home blood pressure monitor, and take readings three or more times daily while on a normal diet, and then on a reduced-salt diet for a week or so, to see if there is any noticeable difference. If not, you can forget the advice about cutting out salt (but note that excess salt can also cause renal {kidney} damage).

Improve your diet

An improvement in general diet can work wonders, helping to reduce surplus body fat and blood fat levels as well as reducing blood pressure by 10 mmHg or more. You have heard it all before, but just as a reminder this means:

Drink alcohol in moderation

A small amount of alcohol (1-2 units per day) may help to protect you from heart disease. One unit is in about half a pint of normal strength beer, or two thirds of a small glass of wine, or one small pub measure of spirits. However, too much alcohol can contribute to hypertension. If you are a heavy drinker, cutting back to the recommended limits (men; 21 units/week, no more than 4/day, women; 14 units/week, no more than 3/day) can reduce systolic blood pressure by up to 10 mmHg.T

Drug treatments

Drug treatment to lower blood pressure is usually advised for:

There are a number of drugs that can lower blood pressure, and your doctor will take into consideration your age and general health, whether you have other medical problems, whether you take other medications, possible side-effects of the drug, your ethnic origin; etc.

Commonly prescribed drugs include:

ACE inhibitors or angiotensin II receptor antagonists (e.g., Ramipril, Losartan) - these make the walls of the blood vessels relax and widen.

Calcium channel blockers (e.g., Amlodipine) or alpha blockers (e.g., Doxazosin) - these also help widen the blood vessels.

Diuretics (e.g., Bendroflumethiazide) - these reduce the volume of blood by increasing the amount of water removed from your blood by your kidneys. This in turn triggers hormones which lower blood pressure.

Beta-blockers (e.g., Atenolol) - these drugs reduce the work your heart has to do, by reducing your pulse rate at times when it may beat too forcefully such as during exercise or when you are feeling stressed.

Alternative treatments

There are several natural alternatives to drugs that are very effective for controlling hypertension. For example, supplements of potassium-rich fruit juices or potassium salts (2 to 4 grams of potassium citrate 3 times a day) will often significantly reduce blood pressure.

Nitrites may also be important. Recent research (Barts Hospital/ London School of Medicine/ Peninsula Medical School) found that in healthy volunteers blood pressure was reduced within an hour of drinking beetroot juice, which is rich in nitrates.

The study, by Barts and the London School of Medicine and the Peninsula Medical School, could suggest a low-cost way to treat hypertension. It took less than an hour to note a reduction in blood pressure in the beetroot juice tests, it was more pronounced after three to four hours and a degree of reduction continued to be observed for up to 24 hours. The researchers showed that nitrate in the juice is converted into nitrites by bacterial decomposition. In the acidic environment of the stomach this is either converted into nitric oxide or enters the circulation as nitrite. The peak time of reduction in blood pressure correlated with the appearance and peak levels of nitrite in the circulation.

Other natural blood pressure stabilisers include guggulsterones, a mixture of several compounds isolated from the plant Commiphora mukul (also called Gum Guggul), and garlic. Clinical trials have shown that fresh garlic (Allium sativum) and garlic supplements may lower cholesterol levels, prevent blood clots, and destroy arterial plaque. A recent study showed that people with hypertension who were given one clove of garlic a day for 12 weeks showed significant reduction of their diastolic blood pressure, and cholesterol levels were also significantly reduced.

Reserpine, an extract of Rauwolfia serpentina, is considered to be the most powerful hypotensive botanical. Only a small dose is required to achieve results and to avoid side effects. Nasal congestion is the most common side effect.

Another recently developed and very effective natural treatment for hypertension is called C12 Peptide, a natural compound derived from milk, that significantly reduces blood pressure. This compound is available as a supplement called Regisense. Similar peptides isolated from the bonito fish have also recently come onto the market, and act in the same way.

Regisense works in almost exactly the same way as the 'ACE-inhibitor' often prescribed by doctors, by inhibiting the action of angiotensin-converting enzyme (ACE). This prevents an inactive precursor hormone called angiotensin-1 from being converted into its active form, angiotensin-2. Angiotensin-2 causes the blood vessels to narrow (vasoconstriction) which raises blood pressure, so by blocking the formation of the hormone, blood pressure is reduced. C12 peptide has been shown to lower blood pressure by 10% when taken in the recommended dose (two 50mg tablets before meals, twice a day). Regisense appears to be free from side-effects and so offers a safer alternative to pharmaceutical ACE inhibitors, which can reduce blood pressure dangerously.