Blood pressure

Blood pressure (BP) is the pressure of the blood in the arteries (the vessels that take blood away from the heart) as the heart pumps it around the body.  The pressure of the circulating blood decreases as blood moves through arteries, arterioles, capillaries, and veins.

How blood pressure is controlled

When the heart contracts, the blood inside the left ventricle is forced out into the aorta and arteries. The blood then enters small vessels with muscular walls, called arterioles. The tone in the muscular walls of the arterioles determines how relaxed or constricted they are. If narrowed, they resist flow. Reduced flow of blood is detected in the brain, the kidneys and elsewhere. Nerve reflexes are stimulated and hormones are then produced. The heart is induced to beat more forcefully so that the blood pressure is maintained at a higher level, to overcome the restricted flow through the arterioles. The achievement of good flow (now at high pressure) eases possible problems for function of the brain and kidneys.

These adjustments occur normally. However, in some people the adjustments become fixed and high blood pressure persists. These people have developed hypertension.

Blood pressure is measured in two ways:

It is best to measure blood pressure when you are relaxed and sitting or lying down.

Systolic – the highest pressure in the arteries when the heart pumps. The normal systolic pressure is usually between 110 and 130mmHg.

Diastolic – the pressure in the arteries as the heart relaxes and fills with blood. The normal diastolic pressure is usually between 70 and 80mmHg.

Blood pressure is measured using a pressure-measuring instrument called a sphygmomanometer.

An inflatable pressure bag is wrapped around the upper arm. The bag is connected to the sphygmomanometer. The operator manually pumps up the bag with air until the circulation of the arm’s main artery is interrupted.

The pressure in the bag is then slowly released until it equals the systolic pressure in the artery, indicated by blood once again moving through the vessel. This makes a ‘thumping’ sound. The systolic pressure is indicated on the sphygmomanometer and recorded.

The blood pressure in the arm’s main artery drops to equal the lowest pressure, which is the diastolic pressure. This is the pressure at which the thumping sound is no longer heard. This figure is also recorded.

The operator may take numerous readings to get the true picture. This is because many people tend to ‘tense up’ during the procedure and nervous tension may temporarily boost the blood pressure.

Blood pressure varies

Blood pressure changes to meet your body’s needs. Systolic (the pressure when the heart contracts) and diastolic (the pressure when the heart relaxes) arterial blood pressures are not static but undergo natural variations from one heartbeat to another and throughout the day. They also change in response to stress, nutritional factors, drugs, disease, exercise, and momentarily from standing up. Sometimes the variations are large.

If a reading is high, your doctor will measure your blood pressure again on several separate occasions to confirm the level. Your doctor may also recommend that you measure your blood pressure at home or have a 24-hour recording with a monitor device. This can be useful if you think you get nervous and it makes your blood pressure rise or if it fluctuates throughout the day.

Hypertension refers to arterial pressure being abnormally high, as opposed to hypotension, when it is abnormally low.

Hypertension can be mild, moderate or severe. Your blood pressure is naturally higher when you are exerting yourself, such as during physical exercise. It is only a concern if your blood pressure is high when you are at rest, because this means your heart is overworked and your arteries have extra stress in their walls.

Factors Controlling Your Blood Pressure

High blood pressure can result from several factors. The heart itself can impact blood pressure. The heart muscles itself can enlarge, causing higher pressure of blood exiting the heart. Enlargement of the heart muscle (Cardiomyopathy) also increases blood pressure. Excess weight makes your heart work harder to pump blood through the body.

Extra fluid in your circulatory system as a result of lots of salt intake, kidney problems or other medical conditions also puts a higher demand on the heart. Increased blood volume also causes more constriction within the blood vessels, translating into higher blood pressure.

The blood vessels play an important role in your blood pressure. Usually, the arteries are elastic and can expand and contract in rhythm with the hearts pumping action. High cholesterol and the plaques that form cause the arteries to lose their elasticity. Each time the heart pumps, the vessel can no longer stretch, and a higher pressure is created. Just think about what happens if you step on a garden hose.

Smoking cigarettes constricts, or tightens your blood vessels, pushing the blood pressure even higher. Some medications you take such as steroids, non-steroidal anti-inflammatory drugs (NSAIDs), nasal decongestants and other cold remedies, diet pills, and anti depressants can also contribute to increased BP. Oral contraceptives, which are hormones, can also raise blood pressure.

Regulating your blood pressure with lifestyle changes.

While medication for regulating your blood pressure can bring significant relief, it is not a cure all by itself. Making some lifestyle changes will go a long way toward regulating your blood pressure, and help keep high blood pressure from returning.

Eat healthy. Choose nutritious foods low in fat and sodium to help reduce the production of plaque in your blood stream, which will assist with regulating your blood pressure.

Quit smoking. Nicotine has been proven to constrict the blood vessels, forcing your heart to pump harder to keep up the flow, working against whatever other measures you are taking for regulating your blood pressure.

Begin a program of low impact exercise to increase your blood flow and help your body to produce more nitric oxide, a substance that helps keep your blood vessels open to wash away plaque build-up. You should also see excess weight drop off, easing stress on your heart muscle and helping with regulating your blood pressure back to a normal level.

By regulating your blood pressure through diet, exercise and doctor prescribed medication, you will be helping yourself to live a longer, and hopefully happier life. Remember to have your blood pressure checked on a regular basis as part of an overall health care program. Regulating your blood pressure just makes good sense.

Have your blood pressure checked regularly

If your blood pressure is ‘normal’ and you have no personal or family history of high blood pressure, a check every two years and during routine visits to your doctor is recommended. If your blood pressure is ‘high-normal’ (or higher) or you have a personal or family history of high blood pressure, stroke or heart attack, it is best to have it checked more frequently. Be advised by your doctor.

Be active every day

Establish or maintain at least 30 minutes of moderate intensity physical activity on five or more days each week (150 minutes per week minimum). This can be accumulated in smaller bouts of 10 minutes or longer, if this is more convenient. Moderate intensity physical activity is activity that causes a ‘moderate’ noticeable increase in depth and rate of breathing while still being able to whistle or talk comfortably. This may include brisk walking, cycling, low-paced swimming or anything that you enjoy that requires the use of your major muscle groups. Some types of exercises, such as lifting heavy weights, should be avoided if you have high blood pressure. Check with your doctor before starting a new activity or increasing your level or intensity. Be active safely: build up your levels of activity gradually.

Enjoy healthy eating

Healthy eating is particularly important in controlling high blood pressure and reducing your risk of heart disease. Enjoying a variety of foods from the different food groups is the key to healthy eating.

Healthy eating is about choosing mainly plant-based foods such as vegetables, fruits and legumes (dried peas, dried beans and lentils); wholegrain bread and cereals; moderate amounts of lean meats, poultry, fish and reduced fat dairy products; and moderate amounts of polyunsaturated and monounsaturated oils and fats.

Reducing salt intake can also help control high blood pressure or help avoid high blood pressure altogether. To reduce salt intake, eat plenty of vegetables, fruit and legumes; choose low salt wholegrain bread and cereals; avoid seasonings, processed foods and takeaway foods (which are high in salt); and avoid adding salt to cooking or at the table.

Other things you can do

Limit alcohol intake to no more than two drinks per day (men) or one drink per day (women).

Achieve and maintain a healthy weight.

Take any blood pressure medication exactly as prescribed. Don’t stop or change your medication unless advised to do so by your doctor.

Antihypertensive medications

In most cases, it is necessary to take antihypertensive medication as well. Usually hypertensive medications are introduced at low doses. The dose may be gradually increased if needed. A second, even a third drug may be added to achieve good blood pressure control. Not many people experience unpleasant side effects.

Any drug treatment for hypertension needs to be monitored carefully by your doctor. You should never alter the dose of your hypertension medication or stop taking it without consulting with your doctor. Medications don’t cure the condition and most of the people who need to take antihypertensive drugs will do so for the rest of their lives.

High Blood Pressure - Hypertension

The heart pumps blood around the body through the blood vessels. Blood pressure is the amount of force exerted on the artery walls by the pumping blood. High blood pressure (hypertension) means that your blood is pumping with more force than normal through your arteries. The added stress on the arteries can accelerate the silting of arteries with fatty plaques (atherosclerosis). Atherosclerosis contributes to many illnesses, such as heart attack and stroke. Other risk factors for atherosclerosis include cigarette smoking and high blood cholesterol.

Hypertension is a common disorder of the circulatory system, affecting around one in seven adult Australians and becoming more common with age. Older people may experience a change in their blood pressure pattern due to their arteries becoming more rigid (less elastic).

Hypertension usually produces no symptoms. This means most people don’t even realise they have it. Experts recommend that everyone should have their blood pressure checked regularly.

Most people with hypertension feel okay. Hypertension usually does not produce any symptoms, because the organs of the body can resist high blood pressure for a long time. That’s why it’s important to have regular medical examinations to make sure your blood pressure isn’t creeping up as you grow older. High blood pressure over a period of time can contribute to many illnesses, including:

• Heart attack
• Heart failure
• Kidney disease
• Stroke

An unhealthy lifestyle can cause hypertension

Some contributing factors to hypertension include:

• Hereditary factors
• Obesity
• Lack of exercise
• A diet high in salt and fats
• Heavy drinking
• Kidney disease
• Age; men over 40, women over 50.

The effects of high blood pressure on the arteries are worsened by:

• Cigarette smoking
• High levels of saturated fat in the diet
• High blood cholesterol
• Diabetes.

Some drugs may cause hypertension

Certain drugs can cause hypertension or make controlling hypertension more difficult. Check with your doctor or pharmacist for alternatives. These drugs include:

The combined contraceptive pill

Non-steroidal anti-inflammatories

Some nasal drops and sprays

Some cough medicines, eye drops and appetite suppressants.

What drives up normal blood pressure?

Plaque is a sticky substance made up of fat and cholesterol that tends to build up in the blood stream, narrowing veins and arteries, and in the worst cases blocking them completely. As the vessels are compromised, the heart has to work harder to push the blood through in order to keep the rest of your vital organs supplied. Over time, this causes the heart muscle to enlarge and weaken, leading to a host of medical problems.

Controlling high blood pressure

If blood pressure remains high it can lead to serious problems. You will be more at risk of these problems if you smoke, are overweight, are physically inactive, have diabetes, have high blood cholesterol, are socially isolated and/or suffer from depression.

Lifestyle is very important to help to control high blood pressure and its associated risks. There are ways you can help to control or prevent high blood pressure. Medications may also be needed and, in some instances, a number of medications may be required long term.

In the past, many medications for regulating blood pressure produced unwanted sexual side effects that many patients felt ruined their quality of life. Today's medications for regulating high blood pressure are much more effective and leave many of those unwanted complications behind. Medications such as ACE inhibitors, alpha and beta blockers, and diuretics are just some of the tools used for regulating high blood pressure the modern way.

Blood pressure (low) - hypotension

Hypotension, or low blood pressure, means that the pressure of blood circulating around the body is lower than normal or lower than expected given the environmental conditions. However, ‘hypotension’ is a relative term – an individual may have low blood pressure compared to others of similar physical characteristics, but may be perfectly healthy.

Low blood pressure is only a problem if it has a negative impact on the body. For example, vital organs (particularly the brain) may be starved of oxygen and nutrients if the blood pressure is too low for that particular individual.

Symptoms

Substantial blood loss can cause a sudden drop in blood pressure (shock). The most dramatic symptom of sudden hypotension is unconsciousness. Usually, low blood pressure develops over time. Symptoms include:

• Light-headedness, when standing from a sitting or lying position
• Unsteadiness
• Dizziness
• Weakness
• Blurred vision
• Fatigue
• Fainting
  

Blood pressure is measured using a device known as a sphygmomanometer. If the measurement drops 30mmHg below the person’s usual blood pressure, this is considered to be hypotension.

Low blood pressure has many different causes including:

• Emotional stress, fear, insecurity or pain (the most common causes of fainting)
• Dehydration, which reduces blood volume
• The body’s reaction to heat, which is to shunt blood into the vessels of the skin, leading to dehydration
• Blood donation
• Internal bleeding, such as a perforated stomach ulcer
• Blood loss from trauma, such as a road accident or deep cut
• Pregnancy
• Medications for high blood pressure
• Diuretics, which produce fluid loss
• Medications for depression
• Medications for certain heart conditions
• Allergic reaction to certain drugs or chemicals
• Some forms of infection, such as toxic shock syndrome
• Heart disease, which can hamper the pumping action of the heart muscle
• Some nervous system disorders, such as Parkinson’s disease
• Addison’s disease (where the adrenal glands fail to produce sufficient blood-pressure-maintaining hormones).

Orthostatic hypotension

Generally, when you stand upright from a sitting or lying position, the blood vessels in your body respond to gravity by constricting. This increases blood pressure. Orthostatic hypotension means that the blood vessels don’t adjust to a standing position and, instead, allow the blood pressure to drop, resulting in a feeling of light-headedness.

Causes include:

Nervous system diseases, such as neuropathy

Prolonged bed rest

Recent Surgery

Dehydration

Irregular heart beat (heart arrhythmia).

Treatment

Treatment for hypotension depends on the cause. For example, the dosages of existing medications may need to be altered or a bleeding stomach ulcer surgically repaired. If no particular cause can be found, drugs may be used to raise blood pressure.