High Blood Pressure

At a glance

Blood pressure is the force of blood pushing against the walls of your arteries.
When that force stays high, it is called high blood pressure (hypertension).

Asan Medical Center says that about 30% of Korean adults are estimated to have high blood pressure.
And more than 90% of cases are "essential hypertension," which has no clear cause.

Where does my blood pressure fall

These are the Korean Society of Hypertension categories. If either the upper (systolic) or the lower (diastolic) number fits, you are in that stage.

| Category | Systolic (upper) | Diastolic (lower) |
|---|---|---|
| Normal blood pressure | under 120 | under 80 |
| Elevated blood pressure | 120~129 | under 80 |
| Pre-hypertension | 130~139 | 80~89 |
| Stage 1 hypertension | 140~159 | 90~99 |
| Stage 2 hypertension | 160 or higher | 100 or higher |
| Isolated systolic hypertension | 140 or higher | under 90 |

A high upper number on its own is still high blood pressure.
As people get older it is common for only the upper (systolic) number to rise,
and this also needs treatment.

The cut-off changes with where you measure

Most people do not know this.

| Where you measured | Cut-off for high blood pressure |
|---|---|
| Hospital or clinic (office) | 140/90 or higher |
| Home (home blood pressure) | 135/85 or higher |
| 24-hour ambulatory (daytime) | 135/85 or higher |

At home you are less tense, so readings come out lower, and the cut-off is lower too.
Think of it this way: 135/85 measured at home means the same thing as 140/90 at the clinic.

One reading is not enough to decide

Asan Medical Center says,
"Diagnosing high blood pressure from a single measurement is not advisable."

Blood pressure goes up and down with the time and the situation.
The decision is made after measuring several times, on several days.

This page is a summary of official sources, for reference only.
Always talk with a healthcare professional about diagnosis and treatment.

Most people feel nothing

Asan Medical Center explains,
"High blood pressure has no clear symptoms, so it is found by chance during a physical or an examination quite often."

When symptoms do appear, they can include headache, dizziness, a pounding heart, and tiredness.
But far more often there are none.

"My head does not hurt, so my blood pressure must be fine" is a dangerous conclusion.
You can only know your blood pressure by measuring it.

So what is the problem

While there are no symptoms, the blood vessels are quietly being damaged.
These are the complications of high blood pressure described by Asan Medical Center.

Brain — the most serious
Bleeding in the brain is the most serious complication of high blood pressure, and
about 80% of stroke patients have high blood pressure.

Heart
The heart muscle thickens and works less well,
leading to heart failure, angina, and myocardial infarction (a heart attack).

Kidneys
At first protein shows up in the urine,
and as it gradually worsens it becomes chronic kidney failure, such as renal failure or uraemia.

Eyes
The blood vessels in the retina are damaged and eyesight can get worse.

Risk factors

These are the risk factors described by Asan Medical Center.

• Family history — a parent or sibling with cardiovascular disease
• Smoking
• High blood lipids, diabetes
• Age 60 and over
• Men, and women after menopause
• Eating a lot of salty food, fat, or alcohol
• Not enough calcium, magnesium, or potassium

If several of these apply to you, check your blood pressure regularly even without symptoms.
The national health check-up (국가건강검진) includes a blood pressure measurement.

Readings taken at the clinic alone are not enough.
A clinic reading is taken a few times a year, and while you are tense at that.
Readings taken at home are much closer to your real blood pressure.

Why it matters — two traps

White-coat hypertension
This is when you are 140/90 or higher at the clinic but under 135/85 at home.
It rises only because you get tense the moment you come in.
It is seen in about 13.5% of patients already on medication.
It can lead to adding medicine you do not need.

Masked hypertension
The opposite. You are normal at the clinic but high when you measure at home.
This one is more dangerous. You have high blood pressure and nobody notices.

Both of these can only be found by measuring at home.

How to measure — Korean Society of Hypertension guidance

When

• Morning — within 1 hour of getting up, after passing urine, before taking medicine
• Evening — just before going to bed

How

• Use a validated automatic blood pressure monitor (an upper-arm cuff is recommended)
• Sit in a chair with a back, rest your back against it, and do not cross your legs
• Keep your upper arm at heart level
• Rest quietly for at least 5 minutes before measuring
• Take 2 readings 1~2 minutes apart, and write down the average

From when

• When you are first being diagnosed, it helps to measure morning and evening for the 5~7 days just before your visit and bring the record

Write it down

A notebook or your phone is fine. Write down the date, the time, and the upper/lower numbers.
You can simply show it as it is at your appointment.

This record is what the medication decision is based on.
Twenty numbers are far more accurate than "it seems a bit high lately."

These ways of measuring give wrong numbers

• ❌ Measuring right after coffee, a cigarette, or exercise
• ❌ Measuring while holding in a full bladder
• ❌ Measuring while talking
• ❌ Measuring with your arm hanging down
• ❌ Getting a high number and measuring again and again right away (it rises the more you measure)
• ❌ Using a wrist monitor in any old position

Do not be alarmed by one high reading.
The point is to look at the average over several days.

Where to go first — a local clinic is fine

• Internal medicine (내과) / family medicine (가정의학과) — starting at a local clinic is fine
• Cardiology (순환기내과, also called 심장내과) — when it is hard to control, or a heart problem is there too

High blood pressure is a condition you live with for life.
The best hospital is the one close to home that is easy to keep going back to.
The worst thing is skipping months because it is too far away.

Departments you may meet because of complications

• Nephrology (신장내과) — when kidney function has declined
• Ophthalmology (안과) — when the retinal blood vessels are damaged
• Neurology (신경과) / neurosurgery (신경외과) — when a stroke has happened
• Cardiology — heart complications

When you go to a bigger hospital

• When 3 or more medicines still do not bring it under control
• When very high blood pressure appears suddenly at a young age (secondary hypertension is suspected and the cause is looked for)
• When complications have developed and specialist treatment is needed

Secondary hypertension is high blood pressure caused by another disease.
It is under 10% of all cases, but treating the underlying disease can cure it.
If you are young and your blood pressure is suddenly very high, it is worth looking for the cause.

For an outpatient visit to a tertiary hospital, you need a referral letter (진료의뢰서) for national health insurance (건강보험) to apply.

You can look for local clinics on the map.

Blood pressure measurement

Asan Medical Center advises measuring while seated, after resting for at least 5 minutes, with the cuff at heart level.
And a diagnosis is not made from a single reading.

24-hour ambulatory blood pressure test

You wear a monitor on your arm and it measures automatically while you go about your day.
Asan Medical Center describes this as the most accurate method.

It is done when white-coat or masked hypertension is suspected, or when night-time blood pressure needs to be checked.

Basic tests done at the same time

It does not end with measuring your blood pressure.
Whether complications have already started, and whether other risk factors are present, are checked as well.

• Urine test — whether the kidneys are damaged (protein in the urine)
• Blood test — blood sugar, cholesterol, electrolytes, kidney function
• Electrocardiogram (ECG) — whether the heart is under strain
• Chest X-ray

When secondary hypertension is suspected

If very high blood pressure appeared suddenly at a young age,
or several medicines still do not control it, extra tests are done to find the cause.

When there is an underlying disease, treating it can sometimes cure the high blood pressure.

The target blood pressure is different for each person

This part matters. Not everyone is aiming for 120/80.
These are the targets in the Korean Society of Hypertension guidelines.

| Situation | Target |
|---|---|
| General high blood pressure with no cardiovascular disease | under 140/90 |
| High-risk group, or existing cardiovascular disease | under 130/80 |
| Diabetes as well | under 140/85 (under 130/80 for the high-risk group) |
| After a stroke | under 140/90 |
| Age 65 and over | systolic under 140 |

Ask your doctor "what is my target blood pressure?" and keep it in mind.
If you do not know your target, the numbers you measure at home tell you nothing.

Lifestyle measures — before medicine, and alongside it

This is what Asan Medical Center advises.

• Weight control — "Weight control is the most important thing." If you are overweight or obese, losing weight also makes the medicine work better
• Less salt — limiting sodium so that you do not take in too much is essential
• Regular exercise
• Less alcohol — heavy drinking is an important risk factor for high blood pressure, and it weakens the effect of the medicine
• Stopping smoking
• More calcium, fiber, and unsaturated fat, and caffeine in moderation

At the pre-hypertension stage, medicine is not used and lifestyle measures alone are followed.
Managing it at this point can delay or prevent the move into high blood pressure.

Medication

Asan Medical Center says that once high blood pressure is diagnosed,
"blood pressure must be brought back to normal with medication."

When medication starts depends on the stage and the level of risk.
For stage 2 hypertension (160/100 or higher), medication is started in every case.

Medication has to go together with lifestyle measures. Taking only the pills and doing nothing else works less well.

If your blood pressure has become normal

It means the medicine is working. It does not mean you are cured.

Stop it on your own and it will rise again.
That said, if you keep up the lifestyle measures, the medicine can sometimes be reduced.
Always decide about reducing or stopping it together with your doctor.

Look at the symptoms, not the number

A high reading on its own is not an emergency.
But it is different when a high reading comes with the symptoms below.

# Call 119 right away for these symptoms

• One side of the face droops, one arm or leg goes weak, or speech is slurred → a stroke is suspected
• Severe chest pain that lasts more than 30 minutes, with a cold sweat → a heart attack is suspected
• The worst headache you have ever had
• Suddenly not seeing well, or seeing double
• Severe shortness of breath
• Becoming confused or drowsy

This is not the time to be measuring your blood pressure again.
Call 119 straight away.

If the number is high but you have no symptoms

• Sit quietly for about 5 minutes to settle, then measure again
• Think back on whether it was right after coffee, a cigarette, or exercise
• If it is still high, see a doctor the same day
• Do not add more medicine on your own judgement

Measuring over and over actually pushes it up.
Do not repeat the measurement many times.

Worth knowing in advance

High blood pressure is the biggest risk factor for stroke and heart attack.
In the end, your family knowing those symptoms is what matters most.

It is worth reading Muromuro's [Stroke] and [Heart attack and angina] pages too.

There are benefits for managing it at a local clinic

When a chronic condition such as high blood pressure or diabetes is managed steadily at a local clinic,
there are programs that lower your out-of-pocket cost.

The names and the conditions have changed over the years, so
ask the local clinic you attend, "do you take part in the chronic disease management program?"
If you qualify, the clinic will register you.

Worth knowing

• High blood pressure is not a condition that automatically qualifies for the special cost-sharing program for serious illness (산정특례) the way cancer does.
• Out-of-pocket costs for visits and medicines differ from item to item.
• There are many kinds of blood pressure medicine and the prices differ. If cost is a burden, say so honestly to your doctor. It can sometimes be adjusted.

Buying a blood pressure monitor

• An automatic monitor with an upper-arm cuff is recommended. Wrist models vary a lot with posture
• Check that it is a validated product
• After buying it, it helps to take it to the clinic and compare it with the clinic's monitor

Use your public health center too

Many public health centers (보건소) run blood pressure checks, counselling, and exercise and nutrition programs
free of charge. Ask the one nearest you.

Programmes and out-of-pocket rates change.
What follows is a summary as of the reference date, so always check the latest rules with the
National Health Insurance Service (국민건강보험공단).