Quick answer: a reading above 180/120 mmHg is considered a hypertensive crisis. If it is still that high after five minutes of rest, call your doctor right away, and call your local emergency number if you also have chest pain, shortness of breath, vision changes, weakness, confusion or trouble speaking. On the low side, a reading below about 90/60 is only dangerous when it comes with symptoms such as fainting, confusion or cold, clammy skin.
Blood pressure categories at a glance
| Category | Systolic (top) | Diastolic (bottom) |
|---|---|---|
| Normal | Below 120 | and below 80 |
| Elevated | 120-129 | and below 80 |
| Stage 1 high blood pressure | 130-139 | or 80-89 |
| Stage 2 high blood pressure | 140 or higher | or 90 or higher |
| Hypertensive crisis | Above 180 | and/or above 120 |
Most people with stage 1 or 2 high blood pressure have no symptoms. The danger is slow, over years, from damage to the heart, brain, kidneys and eyes.
When high blood pressure is an emergency
A reading above 180/120 needs prompt action:
1. Sit down and rest for five minutes, then measure again. Use the correct technique from our guide on how to take blood pressure at home. 2. If it is still above 180/120 and you feel well, call your doctor immediately for advice. This is sometimes called hypertensive urgency. 3. If it is above 180/120 and you have symptoms, call your local emergency number. This is a hypertensive emergency and organs may be at risk.
Symptoms that mean emergency:
- Chest pain or pressure
- Shortness of breath
- Severe headache
- Back pain
- Numbness or weakness, especially on one side
- Vision changes
- Difficulty speaking or confusion
- Seizure
Don’t drive yourself to the hospital.
Which numbers worry doctors in daily life
There is no single number at which everyone is in danger, but these call for a prompt appointment:
- Readings consistently at 140/90 or higher
- Readings at 130/80 or higher on repeated home checks, especially if you have diabetes, kidney disease or heart disease
- A sudden jump from your usual numbers
Dangerously low blood pressure
A blood pressure of 90/60 or lower is generally called low. For many healthy people, especially young, fit people, it is normal and harmless. It becomes a problem when it causes symptoms or drops suddenly:
- Dizziness or lightheadedness on standing
- Fainting
- Blurred vision
- Nausea
- Confusion
- Cold, clammy, pale skin
- Fast, shallow breathing
- Weak, rapid pulse
Low blood pressure with confusion, cold sweaty skin, fast breathing or fainting can signal shock from bleeding, severe infection, dehydration, an allergic reaction or heart problems, and it is an emergency.
Common non-emergency causes include dehydration, blood pressure medicines, heat, long standing, pregnancy and some other medicines. If you feel dizzy, sit or lie down, drink fluids unless told otherwise, and mention it to your doctor.
Pregnancy
In pregnancy, blood pressure of 140/90 or higher after 20 weeks needs prompt medical assessment, because it can signal preeclampsia. A reading of 160/110 or higher, or any high reading with severe headache, vision changes, upper belly pain or sudden swelling, is an emergency. Contact your maternity team or hospital straight away.
What to do after a scare
- Don’t skip or double up on medicine unless your doctor says so.
- Keep a log of readings for a week and take it to your appointment.
- Look at the lifestyle factors in our guide to lowering blood pressure naturally.
- If you have kidney problems or diabetes, ask about tighter targets. See our article on early signs of chronic kidney disease.
Frequently asked questions
Is 150/100 dangerous?
It is stage 2 high blood pressure and needs treatment, though not usually an emergency if you have no symptoms. See your doctor soon.
Is 200/120 an emergency?
It is above the crisis level. Rest and retest after five minutes. If it remains high, call your doctor immediately, and call emergency services if you have any symptoms.
Can anxiety cause a very high reading?
Anxiety can temporarily raise blood pressure, but never assume a very high reading is just anxiety, especially with symptoms.
Is a diastolic number of 120 or more dangerous?
Yes, a diastolic reading above 120 is in the crisis range and should be treated seriously.
Cura Editorial Team
Contributor at Cura Health Journal.