A Useful Guide to Blood Pressure

blood pressure monitor

Blood pressure (BP) refers to the blood’s pressure as it circulates through the blood vessels throughout your body. BP tests are one of the most common measures of overall health – you’ll likely have your blood pressure taken when you enter most medical settings. To maintain your health, it’s essential to precisely understand what it means when someone has ’low’ blood pressure or ‘high’ blood pressure.

In this guide, we will cover the following:

  1. What is blood pressure?
  2. The effects of blood pressure on circulation
  3. The differences between heart rate and blood pressure
  4. Why is maintaining normal blood pressure important?
  5. Understanding your blood pressure reading
  6. Can ethnicity affect average blood pressure?
  7. Factors that affect blood pressure
  8. Low blood pressure (Hypotension)
  9. High blood pressure (Hypertension)
  10. How to promote healthy blood pressure levels
  11. When to see a doctor

What is blood pressure?

Healthcare professionals use blood pressure readings to measure the force of your heart as it pumps your blood throughout your body.[i] Your blood pressure is measured with millimetres of mercury (mmHg). You’ll receive two different figures as a part of your reading: your systolic and diastolic blood pressure.

Systolic (or top number) Measures the pressure that occurs when your heart is pushing blood out

Diastolic (or bottom number) Measures the pressure between heartbeats

 

The effects of blood pressure on circulation

Your blood pressure has a direct impact on your circulation. Both high and low blood pressure can damage your arterial health.

High blood pressure, also called hypertension, causes your arteries to become less elastic, decreasing the amount of blood and oxygen that can make it to your heart.[ii] Over time, this can lead to heart disease, chest pain (angina), a heart attack, or even heart failure.

Low blood pressure, also called hypotension, causes your blood vessels to narrow, which then prompts your heart rate to increase to dilate them.[iii] Some low blood pressure symptoms include dizziness, blurred vision, weakness, confusion, and nausea.

 

The differences between heart rate and blood pressure

Many people get the terms ’heart rate’ and ‘blood pressure’ mixed up, but these terms refer to different things.[iv] Your blood pressure reading measures the force of your blood as it moves through your blood vessels, and your heart rate measures the number of heartbeats per minute.

When your heart rate increases, it does not necessarily mean your blood pressure will increase. If you have healthy blood vessels, they will dilate to accommodate the increased blood flow.

 

Why is maintaining normal blood pressure important?

It is vitally important to prioritise normal blood pressure[v] to maintain cardiovascular and circulatory health. Your blood pressure ensures that all parts of your body receive enough oxygen-rich blood, travelling through your veins, arteries, and capillaries.

 

Understanding your reading

Blood pressure readings are expressed by comparing the systolic and diastolic pressures. For instance, a reading of “135 over 85” translates to 135/85mmHg = systolic pressure of 135 millimetres of mercury (mmHg) and a diastolic pressure of 85mmHg.[vi]

The following is a general guide of blood pressure readings that are considered low, normal and high[vii].

  • Potential high blood pressure – 140/90mmHg or over
    If your blood pressure measures at 140/90mmHg or over, you are likely to have a high blood pressure and are at risk of developing health problems.
  • High-normal or pre-high blood pressure – 120/80mmHg to 140/90mmHg
    This reading is a bit higher than it should be and is a warning sign that high blood pressure could develop.
  • Ideal or normal blood pressure – 90/60mmHg to 120/80mmHg
    This is a healthy blood pressure reading.
  • Potential low blood pressure – 90/60mmHg or lower
    This could indicate an underlying health problem, but usually isn’t an issu

The above measurements are only average’s and everyone’s blood pressure will be slightly different. What is considered low or high for you may be different for someone else.

If you want to find out more about adult blood pressure, Blood Pressure UK have a helpful visual chart which you can access here.

 

Can ethnicity affect average blood pressure?

In the UK, research shows that some ethnic minorities are at an increased risk of health problems associated with high or low blood pressure.[viii] South Asian people are more likely to develop coronary heart disease. African and African Caribbean people are more likely to develop high blood pressure than other groups.

While there is no one clear explanation that explains these increased risks, genetics, lifestyle factors are contributors.

 

Factors that affect blood pressure

Five leading factors affect blood pressure:[ix]

  1. Cardiac Output – Cardiac output refers to the volume of blood flow through your heart through to your ventricles. Increased cardiac output increases blood pressure, while decreased cardiac output decreases blood pressure.
  2. Peripheral Vascular Resistance – Peripheral vascular resistance refers to your arteries ability to expand to accommodate more blood. Increased peripheral vascular resistance increases blood pressure, while decreased peripheral vascular resistance decreases blood pressure.
  3. Circulating Blood Volume – Circulating blood volume refers to the amount of blood circulating through your body. Increased blood volume increases blood pressure, while decreased blood volume decreases blood pressure.
  4. Blood Viscosity – Blood viscosity measures the thickness of your blood. Increased blood viscosity increases blood pressure, while decreased blood viscosity resistance decreases blood pressure.
  5. Vessel Wall Elasticity – Vessel wall elasticity refers to your blood vessels’ ability to return to their original shape after they’ve been pumped full of blood. Increased vessel wall elasticity increases blood pressure, while decreased vessel wall elasticity decreases blood pressure.

 

Low blood pressure (Hypotension)

Here’s what you need to know about low blood pressure:[x]

  • What constitutes low blood pressure?
    Low blood pressure is a reading less than 90/60 mmHg.
  • What causes low blood pressure?
    Low blood pressure has many causes, including your level of fitness, hereditary factors, pregnancy, diabetes, and certain medications. It tends to increase throughout the day.
  • Symptoms and issues that can occur because of low blood pressure
    If you are experiencing low blood pressure, you may not notice any symptoms at all. Some of the most common issues include dizziness, confusion, nausea, blurred vision, and fainting.

If a cause is identified for your low blood pressure, your GP will recommend treatments to ease your symptoms. The recommended treatments may include:

  • Wearing support stockings to increase blood pressure & improve your circulation
  • Changing any medication you are currently taking, or altering the dose

It’s very rare that medication will be prescribed to manage low blood pressure. It can usually be managed ly by treating underlying causes or through lifestyle changes.

 

High blood pressure (Hypertension)

Here’s what you need to know about high blood pressure:[xi]

What constitutes high blood pressure?

High blood pressure is a reading higher than 140/90 mmHg (higher than 150/90mmHg if you’re older than 80).

What causes high blood pressure?

High blood pressure can be hereditary, and its cause is not always easy to determine. However, some of the following factors can contribute to high blood pressure:

  • Being overweight
  • Including too much salt in your diet
  • Drinking too much alcohol or caffeine
  • A sedentary lifestyle
  • Not getting enough sleep
  • Smoking

Health conditions that can occur because of high blood pressure

Having persistently high blood pressure puts you at risk for serious health problems, including heart disease, stroke, peripheral arterial disease, kidney disease, vascular dementia, and heart attack.

 

How to promote healthy blood pressure levels

Here are some ways that you can help to promote healthy blood pressure levels:

  • Food – It’s always a smart idea to eat a varied diet that includes plenty of fresh fruit and vegetables, lean protein, whole grains, and healthy fats. To manage high blood pressure, you should lower your salt intake to around one teaspoonful per day.
  • Exercise Staying active keeps your heart and blood vessels working well, naturally lowering your blood pressure and lessening your risk of stroke and heart disease. The UK government recommends that adults should be moderately active for at least 30 minutes a day, 5 days of the week. If you have high blood pressure you should be able to exercise quite safely, but if you’re thinking of taking up a new activity you should discuss it with your GP. Do what you enjoy – play a tennis game, go for a long walk, take a bike ride, or swim at the local pool.
  • Lifestyle – Lifestyle factors are crucial when it comes to maintaining normal blood pressure. It’s vital to quit smoking, get enough sleep, and reduce the amount of alcohol you consume down to a healthy level.
  • Medication – Most doctors recommend that you alter your diet, lifestyle, and exercise habits before they will prescribe blood pressure medication. However, for some people, medications effectively manage blood pressure levels in the long term.Your GP may prescribe one or more of the following medications:
    • ACE Inhibitors – including enalapril, lisinopril, perindopril, or ramipril
    • Angiotensin-2 receptor blockers (ARBs) – including candesartan, irbesartan, and Olmesartan
    • Calcium Channel Blockers – including amlodipine, nifedipine, or verapamil
    • Diuretics – including indapamide and Bendroflumethiazide. Diuretics can increase urgency and cause urinary incontinence which should be discussed with your GP.
    • Beta-Blockers – including atenolol and bisoprolol

There are several factors which will influence the medicine recommended for you, including your age, ethnicity and how high your blood pressure is.

When to see a doctor

Taking a blood pressure test is the only way of finding out whether you have high blood pressure. If you are over 40, it is advised that you have a blood pressure check every 5 years.

There are many places that you can have your blood pressure checked:

  • your GP surgery
  • some pharmacies
  • as part of your NHS Health Check
  • some workplaces

You can also check it at home with a home blood pressure monitor

Blood pressure checks are quick, easy and having them done regularly could save your life.

Your GP or nurse practitioner will usually take a blood pressure reading at every appointment. If they see that your readings are consistently high or low, they will recommend that you alter your diet and lifestyle to see if this makes a positive change. They may also recommend that you undergo certain tests, including a urine test, blood test and electrocardiogram (ECG). Finally, they may do an ophthalmoscope exam to assess the health of blood vessels at the back of your eyes.

Taking care of your health should always be your top priority. By keeping your blood pressure in the normal range, you can help to prevent many health problems and maintain your quality of life.


Reference list

British Heart Foundation (2020a). Ethnicity. [online] www.bhf.org.uk. Available at: https://www.bhf.org.uk/informationsupport/risk-factors/ethnicity [Accessed 19 Jan. 2021].

British Heart Foundation (2020b). Low blood pressure. [online] Bhf.org.uk. Available at: https://www.bhf.org.uk/informationsupport/heart-matters-magazine/medical/ask-the-experts/low-blood-pressure#:~:text=Symptoms%20of%20low%20blood%20pressure [Accessed 19 Jan. 2021].

Blood Pressure UK (N.D). What do the numbers mean? [online] www.bloodpressureuk.org. Available at: http://www.bloodpressureuk.org/your-blood-pressure/understanding-your-blood-pressure/what-do-the-numbers-mean/ [Accessed 4 March. 2021].

Harvard Health Publishing (2019). Blood pressure and your brain – Harvard Health. [online] Harvard Health. Available at: https://www.health.harvard.edu/heart-health/blood-pressure-and-your-brain [Accessed 19 Jan. 2021].

Heart.org (2016). Blood Pressure vs Heart Rate (Pulse). [online] www.heart.org. Available at: https://www.heart.org/en/health-topics/high-blood-pressure/the-facts-about-high-blood-pressure/blood-pressure-vs-heart-rate-pulse [Accessed 19 Jan. 2021].

NHS Choices (2019a). Blood pressure test. [online] NHS. Available at: https://www.nhs.uk/conditions/blood-pressure-test/.

NHS Choices (2019b). Low blood pressure (hypotension). [online] nhs. Available at: https://www.nhs.uk/conditions/low-blood-pressure-hypotension/ [Accessed 19 Jan. 2021].

NHS Choices (2019c). Overview – High Blood Pressure (hypertension). [online] NHS. Available at: https://www.nhs.uk/conditions/high-blood-pressure-hypertension/ [Accessed 19 Jan. 2021].

NHS Choices (2019d). What is blood pressure? [online] NHS. Available at: https://www.nhs.uk/common-health-questions/lifestyle/what-is-blood-pressure/ [Accessed 19 Jan. 2021].

Open Text BC (2017). Factors That Influence Blood Pressure – Vital Sign Measurement Across the Lifespan – 1st Canadian edition. [online] Opentextbc.ca. Available at: https://opentextbc.ca/vitalsign/chapter/factors-that-influence-blood-pressure/ [Accessed 19 Jan. 2021].

Summit Health Pharmacy (2019). What is Blood Pressure, and Why Is it Important to Be in a Normal Range? | Summit HealthRx Blog. [online] Elevate Your Healthcare. Available at: https://summithealthrx.com/blog/what-is-blood-pressure-and-why-is-it-important-to-be-in-a-normal-range/#:~:text=Normal%20blood%20pressure%20is%20crucial [Accessed 19 Jan. 2021].

 

Sources

[i] https://www.nhs.uk/common-health-questions/lifestyle/what-is-blood-pressure/
[ii] https://www.health.harvard.edu/heart-health/blood-pressure-and-your-brain
[iii] https://www.bhf.org.uk/informationsupport/heart-matters-magazine/medical/ask-the-experts/low-blood-pressure
[iv] https://www.heart.org/en/health-topics/high-blood-pressure/the-facts-about-high-blood-pressure/blood-pressure-vs-heart-rate-pulse
[v] https://summithealthrx.com/blog/what-is-blood-pressure-and-why-is-it-important-to-be-in-a-normal-range/
[vi] https://www.nhs.uk/conditions/blood-pressure-test/
[vii] http://www.bloodpressureuk.org/your-blood-pressure/understanding-your-blood-pressure/what-do-the-numbers-mean/
[viii] https://www.bhf.org.uk/informationsupport/risk-factors/ethnicity
[ix] https://opentextbc.ca/vitalsign/chapter/factors-that-influence-blood-pressure/
[x] https://www.nhs.uk/conditions/low-blood-pressure-hypotension/
[xi] https://www.nhs.uk/conditions/high-blood-pressure-hypertension/

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