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When it’s high blood pressure
For people who were told their blood pressure is high, people who just got a very high reading, and the people beside them. This page passes on, by name, what the National Heart, Lung, and Blood Institute (NHLBI) says: what the two numbers mean, what to do with a very high reading and when it is a 911 call, how to get a true reading at home or at a visit, the habits and the kinds of medicine that bring it down, salt and food, what raises the risk, and high blood pressure in pregnancy. It builds the questions to ask at a visit. Take only what you need today.
A word with a dotted line under it, like this, opens its official definition, quoted from a U.S. government glossary.
Right now
- Call 911 if you have a sudden, severe headache, difficulty breathing, a sudden, severe pain in your abdomen, chest or back, numbness or weakness, a sudden change in vision, or problems talking. That is NHLBI’s list.
- A reading of 180/120 and no symptoms? NHLBI says to wait 5 minutes and check again. If it is still high, call your healthcare provider. Do not wait to see if it comes down on its own.
- Pregnant, or just had a baby? NHLBI says a sudden spike above 160/110 is a medical emergency.
- It can also be a heart attack or a stroke: When it might be a heart attack and When it might be a stroke.
- Thinking about ending your life? Call or text 988, at any hour.
More help
- It might be a heart attack or a stroke: When it might be a heart attack and When it might be a stroke.
- Keeping track: Blood pressure log, My medicines and My emergency card.
- Before a visit: Get ready for your appointment.
- No insurance, a medicine or a bill you can’t pay: When you need a doctor and can’t pay, When you can’t afford your medicine and When a medical bill is too much.
- What often comes with it: When blood sugar goes too low or too high, When it’s your kidneys and When it’s heart failure.
- Food, smoking and sleep: When you need food, When you want to quit smoking and Can’t sleep?
- Pregnancy: Pregnant, or with a new baby.
- Looking after someone: When you’re caring for someone.
- All our free tools.
This page and its wording were written with AI (Claude) for Scarlet Beast (our AI policy). No doctor, nurse, pharmacist or person living with high blood pressure has reviewed it. The facts were read on October 8, 2026 on the websites of the National Heart, Lung, and Blood Institute, part of the National Institutes of Health (nhlbi.nih.gov: its high blood pressure pages on what it is and symptoms, dated April 25, 2024; diagnosis, dated June 26, 2025; and causes and risk factors, treatment, living with it, and pregnancy, dated April 30, 2024), and on October 9, 2026 on its DASH Eating Plan page (dated February 25, 2026). Changed on October 9, 2026: this page used to pass on two more articles, from a publisher that does not allow its text to be reused this way. We stopped relying on them. The sodium limits and the list of foods now come from NHLBI’s DASH Eating Plan page, and we took out what we could not find in the sources we do use: a description of one dangerous form of very high blood pressure, five tips on home monitors and where to be measured, when medicine is usually started at each level, a weekly amount of exercise, a daily limit on alcohol, the names “essential” and “secondary” hypertension, and several added causes, medicines and tests. The caution about potassium and salt substitutes is now marked as ours. The page says whose words it is passing on, and what is marked “ours” is our own. What we left out or did not read: every medicine brand and amount, the names of the medicines NHLBI lists for pregnancy, side effects (the pages we read list none), blood pressure tables for children, where to get a free reading or a low-cost monitor, prices, and anything about what Medicare, Medicaid or private insurance pay for. We left out the DASH plan’s tables of servings. We did not read the other pages NHLBI links to: its tips to reduce salt and sodium, its fact sheet on measuring your own blood pressure, its wallet card, or its list of approved home devices. The sodium figures are the DASH eating plan’s general ones: your provider’s numbers come first. We called no number. It saves nothing and loads no tracking.