Your blood pressure reading consists of two numbers, measured in millimetres of mercury (mmHg):
- The first indicating systolic pressure (higher number):
- This is the force at which your heart pumps blood around your body.
- The second diastolic pressure (lower number).
- This is the resistance to the blood flow in the blood vessels.
Generally, anything between 90/60 mmHg and 120/80 mmHg is considered healthy.
If your blood pressure is too high you will be classed as hypertensive/having hypertension or if too low you will be classed Hypotensive/having hypotension (see below).
UK vs. US
- In the UK:
- The National Institute for Health and Care Excellence (NICE) defines high blood pressure as being more than 140/90 mmHg.
- 150/90 mmHg or higher for those over the age of 80.
- Severe hypertension being 180/120 mmHg or higher.
- In the US:
- You can be diagnosed with hypertension if your blood pressure is 130/80mmHg or higher.
Does Blood Pressure Vary?
Blood pressure is notoriously variable, and factors that can affect it include:
- It changes according to the time of day.
- It is generally lower at night and rising to a peak in mid-afternoon.
- It tends to dip slightly after a meal.
- It is affected by physical activity.
- High blood pressure helps get more oxygen to your muscles.
- It is not unusual to have a systolic pressure of 160 when exercising.
- Lack of exercise and physical activity increases your risk of hyperension.
- Chronic stress can be a cause.
- Stress triggers the production of adrenalin, which makes your heart beat faster, pumping more blood through the system to gear you up for “fight or flight”.
- This response is crucial for survival, but when it fails to switch off, the result is hypertension.
- Long work hours are also linked to stress.
- Heavy drinking or too much alcohol over a prolonged period.
- Coffee or other caffeine-based drinks.
- Not getting enough sleep or having distrubed sleep.
- Being overweight.
- Pregnant women.
- Gestational hypertension affects approximately 6% of pregnancies.
- It is particularly common in women who have diabetes and those who are older than 40 or younger than 20.
- On average, between the ages of 16 and 75, people’s systolic blood pressure goes up by about 20 points.
- Being over the aege of 65.
- Are of African or Caribbean descent.
- Have a relative with high blood pressure.
- Eat too much salt and do not eat enough fruit and vegetables.
- The use of certain drugs.
- Underlying medical condition.
‘Resting’ Blood Pressure
For this reason, medical professionals try to get ‘resting’ blood pressure measurements.
However, that can be problematic also, because having your blood pressure taken can be stressful, which will affect the result (known as the ‘white coat effect’). As a consequence, medical professionals in the UK do not generally act on blood pressure measured in a clinical setting unless it is over 140/90 mmHg.
For those patients whose readings appear elevated, they are increasingly asked to take their own measurements at home. Research demonstrates that blood pressure self-assessment is just as effective in terms of long-term health outcomes.
Blood pressure readings between 120/80mmHg and 140/90mmHg could mean you are at risk of developing high blood pressure if you do not take steps to keep your blood pressure under control.
Blood pressure is individual, meaning what is considered low or high for you may be normal for someone else.
How Do I Check My Blood Pressure?
The only way of knowing whether you have high blood pressure is to have a blood pressure test.
Within England, all adults over 40 are advised to have their blood pressure checked at least every five years. Getting this done is easy and could save your life.
You can get your blood pressure tested at a number of places, including:
- At your GP surgery.
- At some pharmacies.
- As part of your NHS Health Check.
- In some workplaces.
- At home: You can also check your blood pressure yourself with a home blood pressure monitor.
Blood Pressure and Health Outcomes
High blood pressure rarely has noticeable symptoms, but if untreated, it increases your risk of serious problems.
Multiple studies demonstrate that resting blood pressure has a close relationship with cardiovascular outcomes, particularly stroke and hypertensive heart failure.
If your blood pressure is too high, it puts extra strain on your blood vessels, heart and other organs, such as the brain, kidneys and eyes. Persistent high blood pressure can increase your risk of a number of serious and potentially life-threatening health conditions, such as:
- Heart disease;
- Heart attacks;
- Heart failure;
- Peripheral arterial disease;
- Aortic aneurysms;
- Kidney disease; and/or
- Vascular dementia.
Blood Pressure and Insurance
Back in the 1920s, insurance companies started taking readings from large numbers of potential clients – noting the connection between high blood pressure and life expectancy – and refusing cover to anyone with hypertension.
What is Hypertension?
Hypertension is persistently raised arterial blood pressure.
- Primary hypertension:
- Occurs in about 90% of people.
- Has no identifiable cause.
- Secondary hypertension:
- Occurs in a bout 10% of people.
- Has a known underlying cause, such as renal, endocrine, or vascular disorder, or the use of certain drugs.
In general, hypertension is classified according to severity:
- Stage 1 hypertension:
- Clinic blood pressure ranging from 140/90 mmHg to 159/99 mmHg and subsequent ambulatory blood presure monitoring (ABPM) daytime average or home blood pressure monitoring (HBPM) average blood pressure ranging from 135/85 mmHg to 149/94 mmHg.
- Stage 2 hypertension:
- Clinic blood pressure of 160/100 mmHg or higher but less than 180/120 mmHg and subsequent ABPM daytime average or HBPM average blood pressure of 150/95 mmHg or higher.
- Stage 3 or severe hypertension:
- Clinic systolic blood pressure of 180 mmHg or higher or clinic diastolic blood pressure of 120 mmHg or higher.
Accelerated (or malignant) hypertension is a severe increase in blood pressure to 180/120 mmHg or higher (and often over 220/120 mmHg) with signs of retinal haemorrhage and/or papilloedema (swelling of the optic nerve).
‘White-coat’ hypertension is blood pressure that is unusually raised when measured during consultations with clinicians but is normal when measured in other ‘non-threatening’ situations.
Target Clinic Blood Pressure
- Age under 80 years: Clinic blood pressure below 140/90 mmHg; ABPM/HBPM below 135/85 mmHg.
- Age 80 years and older: Clinic blood pressure below 150/90 mmHg; ABPM/HBPM below 145/85 mmHg.
- Postural hypertension: Blood pressure target should be based on standing blood pressure.
- A medical condition consisting of a sudden and abrupt increase in blood pressure when a person stands up.
- Also known as Orthostatic hypertension, it is diagnosed by a rise in systolic blood pressure of 20 mmHg or more when standing.
- Frailty or multi-morbidity: Clinical judgement should be used.
What is Hypotension?
Low blood pressure is a reading of less than 90/60mmHg. It does not always cause symptoms, but you may need treatment if it does.
Symptoms such as lightheadedness or dizziness, feeling sick, blurred vision, generally feeling weak, confusion, and fainting could mean your blood pressure is too low. If you get symptoms when you stand up or suddenly change position, you may have postural hypotension (see postural hypertension above).
What can Cause Hypotension?
There are a variety of causes for low blood pressure including:
- It may be low because you are fit and healthy.
- You may have inherited it from your parents.
- Some people develop low blood pressure as they get older.
- Being pregnant.
- Some medical conditions, such as diabetes.
- Some medicines.
Treatment for Hypotension
If a cause can be found, your medical professional will be able to recommend treatment to ease your symptoms. For example, they may suggest:
- Changing medicines or altering your dose, if this is the cause; and/or
- Wearing support stockings: this can improve circulation and increase blood pressure.
Medicine to increase blood pressure is rarely needed because simple lifestyle measures or treating the underlying cause is usually effective.
Treatment for High Blood Pressure
Your medical professional can help you keep your blood pressure to a safe level using a combination of:
- Lifestyle changes; and
Medicines for High Blood Pressure
If you are diagnosed with high blood pressure, your medical professiona; may recommend taking one or more medicines to keep it under control. These come as tablets and usually need to be taken once a day.
Common blood pressure medicines include:
- ACE inhibitors: Such as enalapril, lisinopril, perindopril and ramipril
- Angiotensin-2 receptor blockers (ARBs): Such as candesartan, irbesartan, losartan, valsartan and olmesartan.
- Calcium channel blockers: Such as amlodipine, felodipine and nifedipine or diltiazem and verapamil.
- Diuretics: such as indapamide and bendroflumethiazide.
- Other diuretics: such as amiloride and spironolactone.
- Beta blockers: Such as atenolol and bisoprolol.
- Alpha blockers: such as doxazosin.
The medicine recommended for you will depend on a number of factors including:
- How high your blood pressure is;
- Your age; and
- Your ethnicity.