How to keep your blood pressure down

High blood pressure is one of the most common ailments in the UK and it can lead to heart disease, eye damage and kidney failure. Here's how to keep it down

Causes –  Diagnosis – Treatment

Five to seven million people in the UK have hypertension, or high blood pressure. It is estimated that up to 50 per cent of cases go undiagnosed. Blood pressure is the amount of force your blood exerts against the walls of your arteries. Normal blood pressure effectively and harmlessly pushes the blood to your body's organs and muscles so they can receive the oxygen and nutrients they need.

Blood pressure is typically expressed as two numbers, one over the other, and is measured in millimetres of mercury (noted as mm/Hg). The first number is the systolic blood pressure, the pressure used when the heart beats. The second number, or diastolic blood pressure, is the pressure that exists in the arteries between heartbeats.

Elevated readings
Depending on your activities, your blood pressure will increase or decrease at different points during the day. It was previously said, that as a rule of thumb, systolic blood pressure should be less than `100 plus age? and diastolic should be less than 80. But over recent years, hypertension has been more specifically defined in adults as persistent systolic of 140 or above, or a persistent diastolic of 90 or above. By this definition, a 60 year old with a systolic of 155 has hypertension, whereas, using the previous guidance, he wouldn?t have been diagnosed as hypertensive.

One elevated reading doesn't necessarily mean you have hypertension, but it is a sign that you should begin closely watching your blood pressure. The World Health Organisation classifies severity of hypertension as follows.

  • Mild: diastolic pressure 90-99, or systolic pressure 140-159
  • Moderate: diastolic pressure 100-109 or systolic 160-179
  • Severe: diastolic pressure 110 or above, or systolic 180 or above.

Risk factors
Hypertension can occur in both children and adults of all races, but it is more common in adults, particularly overweight people, people who drink two to three units or more of alcohol daily, elderly and middle-aged people, and women who are taking oral contraceptives. Additionally, people with diabetes, kidney disease or gout have a higher risk of hypertension, as do people with a family history. Overall, one in four adults has hypertension.

More men than women have hypertension, until women reach their mid-50s, when a woman's risk becomes equivalent to a man's. Studies have shown that having 'Type A' qualities - being highly driven, a perfectionist, quick-tempered and unable to cope well with stress or to relax - increases the risk for hypertension in men, and therefore may also increase the risk for women. Results from an American study indicate that postmenopausal women (aged 50 to 79) who took hormone replacement therapy were more likely to develop hypertension than non-users.

High blood pressure: causes
The cause of approximately 90 to 95 per cent of all hypertension cases can't be determined. This is referred to as essential hypertension. Most people experience no symptoms, but, left untreated, it can result in permanent damage to the small blood vessels of the body, which can damage vital organs and increase the risk of heart attack and stroke. It can also cause acute or chronic circulation problems.

In other cases, hypertension is a symptom of an identified problem and generally corrects itself when the identified cause is corrected. This type of high blood pressure is called secondary hypertension. Potential causes of secondary hypertension are:

Symptoms and complications
Elevated blood pressure levels increase the risk of heart attacks and strokes. Consistent high blood pressure also increases the risk of congestive heart failure and can lead to other problems, such as:

  • Atherosclerosis: Plaque collects on the walls of hypertension-damaged blood vessels, which can eventually lead to blockages in blood vessels such as leg arteries. Although this plaque builds up for many reasons as you age, high blood pressure accelerates the process.
  • Eye damage: High pressure in blood vessels can cause tiny haemorrhages in the retina, the light-sensitive membrane in the back of the eye on which images are formed.
  • Heart enlargement or failure: Hypertension increases the heart's workload. The heart chamber dilates over time and it may eventually be unable to pump blood properly, causing fluid to back up into the lungs.
  • Kidney damage and failure: Hypertension causes arteries going to the kidneys to become constricted, making them less efficient at filtering waste from your body. About 25 per cent of people now on dialysis began with mild, untreated hypertension. Early treatment of hypertension can help prevent kidney damage.
High blood pressure: diagnosis
Your doctor should check your blood pressure at least once every five years. A high blood pressure diagnosis should be based on the average of two abnormal readings per visit, taken at two different visits after an initial screening. It?s usual to leave a month between each set of readings, so the diagnosis is reached after 6 readings taken over a 2-month period. If the readings are very high, the gap between readings is reduced so that treatment is not delayed.

Quick and painless test
The only way to check your blood pressure is to measure it using a sphygmomanometer. This is a quick and painless test in which a rubber cuff is wrapped around your upper arm and inflated. As the cuff inflates, it compresses a large artery, stopping the blood's flow through that artery. When your doctor releases the air in the cuff, he or she can listen with a stethoscope for the blood to start flowing through your artery again.

Your doctor can watch the sphygmomanometer gauge to determine systolic pressure - the pressure when the first sound of pulsing blood can be heard - and the diastolic pressure, which is the pressure when the last sound can be heard.

For many older people, only the systolic blood pressure is high, a condition known as 'isolated systolic hypertension', or ISH (systolic at or above 140 mm Hg and diastolic under 90 mm Hg). Research has found that diastolic blood pressure rises until about age 55 and then declines, while systolic blood pressure increases steadily with age.

Home monitoring
Some people experience so-called 'white coat hypertension', which is elevated blood pressure caused by the anxiety and stress they feel when they visit their doctor. At home, you can check your blood pressure in a setting that's more comfortable for you, and therefore you may get a more accurate reading. Home blood pressure monitoring also gives you the opportunity to measure your own blood pressure when your doctor's surgery is not open. Devices for home blood pressure monitoring are available at large chemists.

Other tests
Once your doctor has diagnosed hypertension, he may want to do some further tests before deciding upon suitable treatment. Some of these tests may be repeated periodically during your follow-up care.

  • A physical examination. Your doctor may check your retinas and abdomen, listen to your lungs and heart, take your pulse in your feet, look for swelling in your ankles, and check your weight and height to calculate your BMI (body mass index).
  • A urinalysis. Your doctor may ask you to urinate into a special container and will send it to a lab for an analysis, looking for elevated protein, sugar, white blood cells, or other abnormalities.
  • An electrocardiogram (ECG). Your doctor may arrange for an ECG to be done in the surgery or make arrangements for it to be done elsewhere. This records electrical activity in the heart. This only takes a few minutes and is painless. The results will be analysed for any abnormalities indicating an enlarged heart or other abnormality.
  • A kidney profile. Your doctor will take blood from your arm and send it to a lab to analyse it, looking for abnormalities such as elevated creatinine.
  • A thyroid profile. Your doctor will take blood from your arm and have it analysed for abnormalities such as an elevated level of thyroid hormone.
  • A chest X-ray. Your doctor may arrange a chest X-ray, looking for enlargement of your heart and main blood vessels.
  • Your doctor may look for other conditions that would increase your risk of heart attacks and strokes, such as diabetes and raised cholesterol. He will also want to know if you are a smoker, as this further increases heart attack and stroke risk.
 High blood pressure: treatment
While there is no cure for hypertension, it is easily detected and usually controllable. Your doctor has seven drug classes, including more than 700 medications, to choose from when selecting a high blood pressure or anti-hypertensive drug. Generally, all of these drugs can lower your blood pressure, but often people respond very differently to each drug. You probably will have to try out a few of them before finding the one that works the best for you with the least amount of side effects.

Types of drugs
There are 4 main classes of drugs that are recommended by the British Hypertension Society as first line treatment for hypertension. The first line treatment, within those 4 classes, depends on a number of other factors including other health problems, age, and ethnic origin. The other 3 drug classes are only used if the `Big 4? don?t do the job, even when given in combination.

  • Diuretics. These rid the body of excess fluids and salt and are the most frequently used drugs to treat high blood pressure. However, in large doses, diuretics deplete the body of potassium, which can lead to irregular heartbeats, and a reduction in glucose tolerance - which can cause diabetes. Still, diuretics are inexpensive and effective.

  • Beta blockers. These drugs reduce your heart rate and therefore your heart's output of blood; however they are not suitable for asthmatics, those with a slow pulse or peripheral vascular disease. They also can mask hypoglycaemia, so you should not take beta blockers if you have diabetes and are on insulin. Some common side effects include fatigue, breathlessness, depression and decreased libido. Other milder side effects can include difficulty sleeping and numbness or tingling of the toes, fingers, or scalp. On the plus side, beta blockers can reduce your risk for second heart attack, irregular heartbeat, angina, and migraines. Until recently, beta blockers were routinely given as first line treatment for hypertension, often combined with a diuretic. However, recent research has suggested that they may not be as effective as the other 3 main classes in preventing strokes, so their use as first line drugs has been modified.

  • Angiotensin-converting enzyme inhibitors (ACE inhibitors). These drugs interfere with the body's production of angiotensin, a chemical that causes the arteries to constrict. This causes the muscle in your arteries to relax, allowing them to widen. The most common side effect is a dry, persistent cough. An added benefit of ACE inhibitors is that they slow the rate at which your kidneys deteriorate if you have diabetes-related kidney disease. However, you should not be on ACE inhibitors if you are pregnant, because they can cause life-threatening foetal complications.

  • Angiotensin II receptor blockers.A newer class of drugs that act on the angiotensin system, these dilate blood vessels and increase the amount of blood the heart pumps out. Their effectiveness can be increased if diuretics are given at the same time. These drugs do not cause you to cough as ACE inhibitors may.

  • Calcium channel blockers (calcium antagonists). These also affect your heart rate and relax your blood vessels, though one study suggests that postmenopausal women taking calcium channel blockers have twice the risk of developing breast cancer than older women taking other types of blood pressure drugs or no blood pressure drugs. There are three main types of calcium blockers, with very different side-effect profiles.Some may cause ankle swelling, rapid heartbeat, and headaches, and may make you flush. Others can cause constipation and can interfere with the heart's ability to pump the proper amount of blood flow. The third type can cause nausea, headaches, and can also interfere with the way your heart pumps blood.