High blood pressure

Also known as hypertension

High blood pressure (hypertension) is a common condition in which the force of your blood against your artery walls is too high, too often. Ongoing high blood pressure puts stress on your heart and can lead to health problems, such as heart disease and stroke.

Key points

  1. One in five New Zealanders has high blood pressure, but most don't know they have it.
  2. High blood pressure usually doesn't have symptoms, so the best way to find out if you have high blood pressure, is to get your blood pressure checked regularly. Your doctor, nurse or pharmacist can do this for you.
  3. Untreated high blood pressure can cause serious problems such as stroke, heart attack and kidney failure.
  4. You can manage high blood pressure through healthy lifestyle choices and medications if needed.
  5. If you need medication, take it every day as prescribed. If you have any questions, ask your doctor or pharmacist.

undefined

What is high blood pressure?

Blood pressure (pēhanga toto) is the force of your blood pushing against the walls of your arteries. Read more about blood pressure.

Blood pressure is measured in millimetres of mercury (which is written as mmHg). Blood pressure readings are a combination of two measurements:

  • Systolic – the highest pressure against your arteries as your heart pumps. The normal systolic pressure is usually between 110–130 mmHg.
  • Diastolic – the pressure against your arteries as your heart relaxes and fills with blood. The normal diastolic pressure is usually between 70–80 mmHg.

High blood pressure may be considered to be 140/90 mmHg or higher. However, it is difficult to give an example of a high blood pressure reading, because it depends on the individual. The level of blood pressure that is high for you depends on lots of different factors and your overall risk of heart attack or stroke. Generally, the lower your blood pressure, the better. If you have a history of heart disease, diabetes or a high risk of heart attack or stroke, it's recommended you lower your blood pressure to less than 130/80. See Who needs to get their blood pressure checked?

A single high blood pressure reading does not necessarily mean that you have high blood pressure. It's normal for your blood pressure to rise and fall during the day, depending on what you have been doing (eg, exercise) and how you are feeling (eg, stressed).

You are usually considered to have high blood pressure if your blood pressure stays high for 3 separate readings, over at least 3 months. For some people, doing measurements at home with a machine can be more accurate than doing it in the clinic with your doctor or nurse. 

To find out if you need to do something about your blood pressure levels, visit your doctor and have a heart and diabetes check. In your heart and diabetes check, your doctor, nurse or other health professional will discuss your ideal blood pressure, taking into account your overall risk of having a heart attack or stroke.

Why is high blood pressure a problem?

Over time, high blood pressure damages your blood vessels. It can lead to the following complications.

Complications of having high blood pressure  Description
Heart attack

 

High blood pressure damages arteries that can become blocked and prevent blood flow to the heart muscle.
Angina High blood pressure can lead to heart disease or microvascular disease, of which angina, or chest pain, is a common symptom.
Stroke High blood pressure can cause blood vessels in your brain to clog more easily or even burst.
Heart failure The increased workload from high blood pressure can cause your heart to enlarge and fail to supply blood to your body.
Kidney disease or kidney failure High blood pressure can damage the arteries around your kidneys and interfere with their ability to filter blood effectively.
Eyesight problems High blood pressure can strain or damage blood vessels in your eyes and can lead to loss of vision.
Peripheral artery disease  Atherosclerosis caused by high blood pressure can cause a narrowing of arteries in your legs, arms, stomach and head, causing pain or fatigue.
Sexual problems High blood pressure can lead to erectile dysfunction in men or lower libido in women.


Image credit: 123rf

What causes high blood pressure? 

High blood pressure often runs in families. Sometimes kidney or glandular disease may be responsible. However, eating too much salt, drinking too much alcohol, being overweight and not moving around enough each day can also contribute to high blood pressure and heart disease.

The effects of high blood pressure on your blood vessels are worsened by:

  • cigarette smoking
  • high levels of saturated fat in your diet
  • high blood cholesterol.

Some medicines may cause raised blood pressure or make controlling it more difficult. These medicines include:

  • the combined contraceptive pill
  • non-steroidal anti-inflammatories (NSAIDs)
  • some nasal drops and sprays
  • some cough medicines, eye drops and appetite suppressants.

Check with your doctor or pharmacist for alternatives.

Who needs to get their blood pressure checked?

Every adult should have your blood pressure checked regularly. The age you are advised to start having heart and diabetes checks depends on your age, ethnicity and other risk factors. 

Risk factors Age to start having heart and diabetes checks

If you have no known risk factors

Men: 45 years
Women: 55 years

If you are Māori, Pasifika or South Asian1

Men: 30 years
Women: 40 years

If you have the following risk factors:

  • you smoke
  • you have a family history of diabetes, high cholesterol, heart attack or stroke2
  • you have gestational diabetes (diabetes during pregnancy) or prediabetes
  • you are overweight3
  • you have kidney disease
  • you have high blood pressure or cholesterol
  • you have previously had a heart trouble or stroke
  • you have a heart condition such as atrial fibrillation.
Men: 35 years
Women: 45 years

If you have diabetes (type 1 or 2)

As part of your yearly diabetes review

If you have schizophrenia, major depressive disorder, bipolar disorder or other severe mental illness

25 years
  1. South-Asian peoples: Indian, including Fijian Indian, Sri Lankan, Afghani, Bangladeshi, Nepalese, Pakistani, Tibetan
  2. Family history: parent, brother or sister
  3. Overweight: BMI ≥ 30 or weight around your tummy (waist circumference ≥ 102 cm in men or ≥ 88 cm in women)

Read more about heart risk assessment.

How is high blood pressure diagnosed? 

High blood pressure does not usually have any symptoms, so the only way to find out if you have it is to get your blood pressure checked by your doctor, nurse or pharmacist. They will often take several readings over weeks or months to see what the trend is.

Your doctor may suggest 24-hour blood pressure monitoring. This involves wearing a blood pressure unit for up to 24 hours to collect a series of blood pressure and heart-rate readings at different times of the day and night. Read more about 24-hour blood pressure monitoring Heart Foundation, NZ

How is high blood pressure treated?

Your doctor will work out your five-year risk of cardiovascular disease (eg, heart attack or stroke) to work out the likely benefits of blood pressure-lowering interventions.

If you have low risk, following the self-care steps listed below, such as stopping smoking, eating a balanced diet, less salt, less alcohol and becoming more physically active, may be enough. If your risk is higher, you are likely to need medication as well as following the self-care steps.

Self-care for high blood pressure

  • Stop smoking  quitting is the most important step to reduce your risk of heart attack and stroke.
  • Achieve and maintain a healthy body weight. The more overweight you are, the more strain you put on your heart and cardiovascular system. For some people, losing 5–10kg of excess weight is enough to get your blood pressure back to normal. Check with your doctor, nurse or pharmacist as to what is right for you.
  • Eat a balanced diet low in saturated fat with whole grains, 8 servings of coloured vegetables and fruit, and 2 to 3 servings of low-fat milk or milk products a day. Learn more about the DASH eating plan to lower high blood pressure.
  • Eat less salt – use herbs, spices, citrus and vinegar for flavouring and dressings, choose low-salt versions of packaged foods, avoid pickled food and salty or fatty takeaway foods. Read more about reducing salt intake
  • Limit alcohol consumption and follow recommended guidelines for low-risk drinking.
  • Be active every day. Find ways to put a little bit more activity in your day at every opportunity. Take the stairs at work. Park 5 minutes further away. Aim to get 30 to 60 minutes of moderate activity most days of the week. Walking, cycling and swimming are ideal. Find an activity you enjoy so you can keep it up. Find out more about getting active.
  • Avoid eating large quantities of liquorice – it contains a chemical that can raise blood pressure. 

Medicines for high blood pressure

Medications can help control high blood pressure and reduce the damage from high blood pressure, but they do not cure it. Usually, medication will need to be taken for life, unless losing weight and the lifestyle changes are so successful that your blood pressure returns to normal levels without medication.

There a variety of medicines that can be used to lower blood pressure. Each of these groups of medicines works differently. Sometimes 2 or 3 medications are needed and it may take time to find the right combination and dosage. Tell your doctor or pharmacist about any side effects you may have and  follow instructions carefully.

Examples of medicines to treat blood pressure include:

  • ACE inhibitors such as cilazapril, lisinopril, quinapril.
  • ARBs such as candesartan, irbesartan, losartan.
  • Beta blockers such as bisoprolol, metoprolol, propranolol.
  • Calcium channel blockers such as amlodipine, diltiazem, felodipine.
  • Diuretics (also called water pills) such as bendroflumethiazide, chlortalidone, indapamide.

Read more about medicines to treat blood pressure.

Because high blood pressure puts you at increased risk of cardiovascular disease, you may also be prescribed other medicines to help reduce your risk of heart disease and stroke, such as:

Learn more

DASH Eating plan to lower high blood pressure
High blood pressure personal stories Health Talk online
High blood pressure  Heart Foundation NZ
High blood pressure NHS, UK
Family health history Learn Genetics (Genetic Science Learning Centre), University of Utah, USA, 2015
High blood pressure & the cardiovascular system Watch, Learn, Live: Interactive Cardiovascular Library, American Heart Association

References

  1. Managing high blood pressure Heart Foundation, NZ 
  2. Health threats from high blood pressure American Heart Association, 2016
  3. Blood pressure (high) – hypertension Better Health Channel, Australia, 2011
  4. What's my risk of a heart attack or stroke? Heart Foundation, NZ
Credits: Health Navigator Editorial Team .