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Is 171/118 Blood Pressure Severe Hypertension?

171/118 blood pressure is classed as a ‘Hypertension Stage 3’ blood pressure reading by the EU and Japan, also known as ‘Severe’, and as a ‘Hypertension Stage 2’ reading by UK and US standards.

What does 171/118 blood pressure mean?

What 171 over 118 blood pressure means:

A BP reading of 171 over 118 means your blood pressure is classed at either Hypertension Stage 3 (Severe), or Stage 2 depending which nation’s scale you look at and whether it was recorded at home or at a medical office; a systolic pressure (when the heart contracts on a beat) reading of 171 mmHg and a resting, diastolic pressure (when the heart is dilated or relaxing between beats) reading of 118 mmHg. Blood pressure readings are presented in millimetres of mercury, the units being mmHg (see why here).

You may find it written as blood pressure 171 over 118, or more simply BP 171/118

Reads Systolic Diastolic
171-over-118 171 118

Looking at your systolic and diastolic numbers independently, means they would each fall into the following categories:
  • A systolic reading of 171 is generally considered to be at the ‘hypertension stage 2’ level.
  • A diastolic reading of 118 is generally considered to be at the ‘severe hypertension’ level.

Both your systolic and diastolic blood pressure readings are important to consider, generally the one with the less healthy status determines your overall blood pressure condition. In your case your overall blood pressure classiciation would be considered at the severe hypertension level, as your systolic reading is healthier when comparing it to your diastolic reading.

You can see your blood pressure readings of 171 over 118 plotted on the chart above, noting that your overall classification for this BP reading falls into the severe hypertension blood pressure range.

Minor variations exist in the naming conventions and specific boundaries of each category between different nations. We show what these differences are in the tables presented later in this article so you know where you stand on the EU, US, UK, Japan and International Society of Hypertension (ISH) scales and plot you on the United States’ blood pressure chart too. It is important to consider that a single blood pressure reading is not definitive and it can be affected by a number of factors.

It is recommended that you take your blood pressure readings regularly, with one of the many cost effective home blood pressure monitors (also known as sphygmomanometers or blood pressure gauges). You can then use a reasonable average of the readings to analyse and better understand if your blood pressure is okay overall, or whether you need to make some changes to your lifestyle and start working towards a lower blood pressure. Refrain from jumping to conclusions over any single measurement.

The column chart of your blood pressure is shown above and displays the status of your systolic reading (higher blood pressure number) of 171mmHg compared to your diastolic reading (lower blood pressure number) of 118mmHg. Using these two blood pressure figures, you can also then find out what your blood pulse pressure is.

What Is Blood Pulse Pressure?

The difference in value between your systolic and diastolic readings, which are shown on the blood pressure chart above, is known as pulse pressure. Your pulse pressure is therefore 53mmHg, calculated by subtracting your diastolic reading of 118mmHg from the systolic reading of 171mmHg.

A normal pulse pressure is typically considered to be around 40mmHg. Your pulse pressure will vary naturally with different blood pressure readings but the variation will typically be in the 5 to 10 mmHg range. As always, it is best to take a number of different readings to determine a truly representative average.

A pulse pressure which is less than 25% of your systolic pressure is considered concerningly low and over 100%, would be considered wide. Your pulse pressure of 53mmHg as a percentage of your systolic reading of 171mmHg comes in at 31%.

Having a small pulse pressure reading, variably known as a low pulse pressure or narrow pulse pressure, tends to mean that the heart is generally pumping less blood through it when it beats than desired and it can occur in association with various heart valve diseases or heart failure. It will also appear in cases of internal bleeding or significant blood loss from a physical injury.

Wide pulse pressure on the other hand, which can also be referred to as high pulse pressure, can occur during exercise and is regularly seen in endurance athletes and high muscle-mass individuals without much concern. However, for less active and aging individuals that may be experiencing hardening of the arteries, a wide pulse pressure develops for different reasons and that can be a warning sign of increased risk of stroke, heart rhythm problems and heart disease.

If you are concerned about your pulse pressure, ask your healthcare professional for advice.

Different Countries May Interpret 171/118 Differently

Your 171/118 reading is seen as Hypertension Stage 2 in some countries and Stage 3 in others, the specific boundaries for each category and the naming of them can vary slightly between nations such as stage/grade or at the upper levels stage 3/severe/crisis etc.

Revisions to these scales also occur, notably in 2017, leading U.S. health groups, including the American College of Cardiology and the American Heart Association, set lower levels for what counts as the start of high blood pressure and removed the term prehypertension from their scale. Yet when the EU later reviewed their scale in 2018, they maintained a higher boundary for the start of hypertension. So, large segments of the US population defined as having high blood pressure would not be considered to be suffering from hypertension by the EU. The UK also used to consider a diastolic reading over 110 mmHg as severe but this boundary was later moved up to be greater than 120 mmHg.

Where Does My Blood Pressure Plot On The American College of Cardiology (ACC) and American Heart Association (AHA) Hypertension Scale?

The ACC/AHA hypertension scale was most recently revised in 2017 and the major change at that time was lowering the definition of the start of hypertension from ≥140/≥90 mmHg to ≥130/≥80 mmHg. It also re-classified “prehypertension” as “elevated” blood pressure (120-129/<80 mmHg).

Your blood pressure readings on the ACC/AHA scale are shown below:

On the chart above you can see your blood pressure reading, this time plotted on the ACC/AHA hypertension scale giving an overall status of hypertension stage 2.

The column chart above again compares your systolic (higher blood pressure number) reading of 171 to the diastolic (lower blood pressure number) reading of 118 and the status they have if considered individually, this time on the ACC/AHA hypertension scale giving you a systolic status of hypertension stage 2 and a diastolic status of hypertension stage 2.

Categorisations of Blood Pressure by Region/Country

Here we present the latest revised blood pressure tables and naming terms used by the EU, US, Japan, UK and International Society of Hypertension (ISH). Some differentiate office vs home readings, office not meaning your workplace but the office of the medical staff. The reason this differentiation is made is because medical environments can be stressful and raise the readings compared to what is achieved when relaxing at home and taking your own measurements.

European Society of Cardiology (ESC) and the European Society of Hypertension (ESH) Classifications

Since 2023: source
Category Systolic (mmHg) Diastolic (mmHg)
Optimal (Ideal) <120 and <80
Normal 120–129 and/or 80–84
High normal 130–139 and/or 85–89
Grade 1 hypertension 140–159 and/or 90–99
Grade 2 hypertension 160–179 and/or 100–109
Grade 3 hypertension ≥180 and/or ≥110
Isolated systolic hypertension ≥140 and <90
Isolated diastolic hypertension <140 and ≥90

American College of Cardiology (ACC)/American Heart Association (AHA) Classifications

Since 2017: source
Category Systolic (mmHg) Diastolic (mmHg)
Normal <120 and <80
Elevated 120-129 and <80
Stage 1 130-139 or 80-89
Stage 2 ≥140 or ≥90
Hypertensive crisis >180 and/or >120

Japanese Society of Hypertension (JSH) Classifications

Since 2019: source
Classification Office blood pressure (mmHg) Home blood pressure (mmHg)
SBP DBP SBP DBP
Normal blood pressure <120 and <80 <115 and <75
High normal blood pressure 120–129 and <80 115–124 and <75
Elevated blood pressure 130–139 and/or 80–89 125–134 and/or 75–84
Grade I hypertension 140–159 and/or 90–99 135–144 and/or 85–89
Grade II hypertension 160–179 and/or 100–109 145–159 and/or 90–99
Grade III hypertension ≥180 and/or ≥110 ≥160 and/or ≥100
(Isolated) systolic hypertension ≥140 and <90 ≥135 and <85

UK National Health Service (NHS)/British Heart Foundation(BHF) Classifications

Since 2023: source
Classification Office blood pressure (mmHg) Home blood pressure (mmHg)
SBP DBP SBP DBP
Low blood pressure <90 <60 <90 <60
Normal blood pressure (Under 80s) 90–120 60–80 90–120 60–80
Normal blood pressure (Over 80s) <150 <90 <145 <85
High-normal blood pressure (pre-hypertension) 120–140 80–90 120–140 80–90
Stage one 140–160 90–100 135–150 85–95
Stage two 160–180 100–120 >150 >95
Stage three (Severe hypertension) >180 >120 N/A N/A

International Society of Hypertension (ISH) Classification

Since 2020: source
Category Systolic (mm Hg) Diastolic (mm Hg)
Normal BP <130 and <85
High-normal BP 130–139 and/or 85–89
Grade 1 hypertension 140–159 and/or 90–99
Grade 2 hypertension ≥160 and/or ≥100

What Is A Normal Blood Pressure Range?

Ideally your blood pressure should be between 90/60mmHG and 120/80mmHg to be considered within the normal blood pressure range, also known as the normotension range. The main concern however, often referred to as the “silent killer,” is high blood pressure or hypertension, which rarely has obvious symptoms. The World Health Organisation estimates 1.28 billion adults aged 30-79 have high blood pressure, with 46% of those unaware that they have it. If left untreated persistent hypertension can increase your risk of a number of serious and potentially life-threatening health conditions, such as:

    – aortic aneurysms
    – heart attacks
    – heart disease
    – heart failure
    – kidney disease
    – peripheral arterial disease
    – strokes
    – vascular dementia

If you have high blood pressure, reducing it even a small amount can help lower your risk of experiencing these potentially life threatening conditions.

Should I be concerned about my overall ‘severe hypertension’ or ‘hypertension stage 2’ blood pressure classifications?

Yes. Your blood pressure’s overall status comes in as being at the ‘severe hypertension’ level in general. On the ACC/AHA (American College of Cardiology/American Heart Association) scale however, the hypertensive crisis level starts at a slightly higher 120 mmHg diastolic reading rather than 110mmhg, so it is still considered ‘hypertension stage 2’ on their scale.

Either way, if your blood pressure is consistently at these sorts of numbers, it is reaching a really high level with increased chance it could lead to a stroke – your readings should be checked with your doctor or pharmacy within the next couple of days. With blood pressures at the upper end of these levels, blood vessels may become inflamed causing damage to them, fluid or blood may leak from them which means the heart is unable to pump blood and oxygen around the body effectively.

You may not notice any severe hypertension symptoms but those associated with severe hypertension/hypertensive crisis blood pressure can include:

  • Severe headaches
  • Dizziness
  • Nausea
  • Severe anxiety
  • Shortness of breath
  • Seizures
  • Unresponsiveness
  • Chest pain
  • Blurry vision
  • Fluid on the lungs (pulmonary edema) or fluid build-up in tissues

Once blood pressure reaches severe hypertension or hypertensive crisis levels you may, or may not, experience damage to your organs. If damage to your organs has occurred it becomes an emergency situation associated with life threatening complications. Treatments may include hospitalisation, intravenous and oral medications.

Causes of hypertensive emergency may include:

  • Heart Attack
  • Stroke
  • Heart failure
  • Not taking prescribed blood pressure medication
  • Heart failure
  • Kidney failure
  • Rupture of the aorta artery (aneurysm)
  • Incompatible medicine interactions
  • Pregnancy eclampsia (convulsions)

Lifestyle changes to lower blood pressure become less effective at these sorts of levels, particularly with the urgency required to reduce it, so blood pressure medicine will most likely be prescribed to quickly bring down blood pressure. Arrange to consult with a medical professional at the earliest opportunity.

Key Takeaways:

  1. Blood Pressure Classification: A blood pressure reading of 171/118 is classified as:
    • ‘Hypertension Stage 3’ (Severe) by the EU and Japan.
    • ‘Hypertension Stage 2’ by UK and US standards.
  2. Understanding the Reading:
    • Systolic Pressure (when the heart contracts): 171 mmHg
    • Diastolic Pressure (when the heart relaxes): 118 mmHg
  3. Blood Pulse Pressure:
    • Pulse pressure is the difference between systolic and diastolic readings. For a reading of 171/118, the pulse pressure is 53mmHg. A normal pulse pressure is typically around 40mmHg.
    • Your pulse pressure of 53mmHg as a percentage of your systolic reading of 171mmHg is 31%.
  4. Variations in Classification: Different countries and organizations have their own scales and definitions for hypertension. It’s essential to be aware of these differences and understand where your blood pressure stands on various scales.
  5. Potential Health Risks: Persistent hypertension can significantly increase the risk of various health conditions, including heart attacks, strokes, kidney disease, and vascular dementia.
  6. Urgent Symptoms of Severe Hypertension: While many people with high blood pressure don’t experience any symptoms, those with severe hypertension might experience severe headaches, dizziness, nausea or vomiting, severe anxiety, shortness of breath, seizures, chest pain, a fast, irregular or pounding heartbeat and blurry vision. If you are experiencing symptoms like these alongside severe BP readings, seek medical attention immediately.
  7. Immediate Recommendations:
    • It is critical for anyone with blood pressure readings at these levels to consult with a medical professional as soon as possible.
    • Lifestyle changes can help in the longer term, but medication might be necessary to quickly reduce blood pressure from these dangerous levels.

It is vital to consult with healthcare professionals regarding blood pressure readings and any concerns related to it. Do not delay if your readings are consistently high. As the ISH says, hypertension “is the leading cause of death worldwide, affecting more than 1.4 billion people and accounting for more than 28,000 deaths each day.”

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