Blood pressure is the pressure of the blood in the arteries as it is pumped around the body by the heart. Blood pressure does not stay the same all the time. It changes to meet your body’s needs. It is affected by various factors, including body position, breathing, emotional state, exercise and sleep.
If blood pressure remains high, it can lead to serious problems like heart attack, stroke, heart failure or kidney disease. The medical name for persistently high blood pressure is hypertension
and the medical name for low blood pressure is hypotension
Measuring blood pressure
Blood pressure is usually measured by wrapping an inflatable pressure cuff around your upper arm. This cuff is part of a machine called a sphygmomanometer. It is best to measure blood pressure when you are relaxed and sitting.
Blood pressure is recorded as two numbers, such as 120/80. The larger number indicates the pressure in the arteries as the heart pumps out blood during each beat. This is called the systolic blood pressure. The lower number indicates the pressure as the heart relaxes before the next beat. This is called the diastolic blood pressure. Both are measured in units called millimetres of mercury (mmHg).
Variations in blood pressure
Your blood pressure changes to meet your body’s needs. If a reading is high, your doctor may 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 monitoring device.
Blood pressure readings
There is no ‘normal’ or ‘ideal’ blood-pressure reading. The following figures should only be used as a guide:
- optimal <120/<80
- normal 120-129/80-84
- high-normal 130-139/85-89
- mild hypertension 140-159/90-99
- moderate hypertension 160-179/100-109
- severe hypertension ≥180/≥110
High blood pressure usually does not give warning signs. You can have high blood pressure and feel perfectly well. The only way to find out if your blood pressure is high is to have it checked regularly by your doctor.
Low blood pressure is relative – what is low for one person may be okay for another – and is only considered a problem if it has a negative impact on your body. In general, you are considered to have low blood pressure if either number measures 30mmHg below your usual blood pressure reading.
Regular blood-pressure checks
If your blood pressure is ‘normal’ and you have no other risk factors for cardiovascular disease, and no personal or family history of high blood pressure, you should still have a check every two years and during routine visits to your doctor.
If your blood pressure is ‘high–normal’ (or higher), or if you have other risk factors for cardiovascular disease, a personal or family history of high blood pressure, stroke or heart attack, it is best to have it checked more frequently. Ask your doctor for advice.
Managing high blood pressure
If your blood pressure remains high, it can lead to serious health problems. You will be more at risk of these problems if you:
- are overweight
- are physically inactive
- have diabetes
- have high cholesterol
- are socially isolated
- have depression.
Lifestyle changes are very important to help manage high blood pressure and lower your risk of cardiovascular disease. Suggestions include:
- Achieve and maintain a healthy weight.
- Be physically active.
- Limit your alcohol intake to no more than two drinks a day (men) or one drink a day (women).
- Quit smoking.
- Decrease your salt/sodium intake.
- Increase your potassium intake by eating a wide variety of fruit, vegetables, plain unsalted nuts and legumes.
Some people may also need medicine to manage high blood pressure, but it is still important for them to make lifestyle changes too.
High blood pressure and daily activity
Try to do at least 30 minutes of moderate-intensity physical activity on most, if not all, days of the week. This can be done in bouts of 10 minutes or longer, if that is more convenient.
Physical activity is any form of bodily movement performed by our large muscle groups. Moderate-intensity physical activity (energetic activity that doesn’t make you breathless), such as brisk walking or cycling, is enough to provide health benefits.
Some types of exercises, such as body presses and lifting heavy weights, can actually raise your blood pressure. You should avoid these 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.
High blood pressure and diet
Following a diet that emphasises the intake of vegetables, fruits and whole grains, including low-fat dairy products, such as in the Dietary Approaches to Stop Hypertension (DASH) diet, may be combined with exercise and weight loss to maximise blood pressure reduction.
Healthy eating is important in managing 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. Every day, try to include:
- whole grains
- lean meats
- oily fish
- reduced-fat, low-fat or no-fat dairy products
- monounsaturated or polyunsaturated vegetable and seed oils
- nuts, seeds and legumes.
Salt intake and high blood pressure
Reducing the amount of salt you eat can also help to manage or even avoid high blood pressure. To help reduce your salt intake you should:
- Choose low-salt or reduced-salt food where available.
- Avoid adding salt to cooking or at the table – flavour meals with herbs and spices instead.
- Avoid high-salt foods, such as potato crisps or chips, salted nuts, commercial sauces (such as tomato, soy and fish), processed meat and most takeaway foods.
Medications for high blood pressure
There is a large variety of medicines available to lower and manage high blood pressure. Your doctor may call them antihypertensives.
These medications do not cure high blood pressure, but they do help manage it. Once you start to take medicines to manage your blood pressure, you may need to take them for the rest of your life. However, the dose of these medicines may change over time.
If you need to take medication, your doctor will advise you on the correct type and dose. Two or more different medications are often needed to manage blood pressure.
Make sure that you take your medicines regularly. Some things that may help you remember to take them include:
- taking them at the same time each day
- using a weekly pill box
- marking the time on your calendar
- asking a family member or friend to remind you
- always carrying a list of your medicines and their doses with you
- entering a daily alarm in your mobile phone to remind you.
Take any blood pressure medicine exactly as prescribed. Don’t stop or change your medicine, unless your doctor advises you to.
Blood pressure and potassium
Generally, people with high blood pressure should increase their potassium intake through their diet. However, this recommendation may not apply to some people, such as people whose kidneys don’t function normally or who are taking certain medicines. Ask your doctor for more information.
Where to get help
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