Sort the situation before you pick up the phone

The AHA's current advice for a reading of 180/120 mm Hg or higher is to wait at least 1 minute and measure again. If the second reading is still that high and you have none of the seven symptoms above, the AHA describes the situation as severe hypertension. In its words, this "usually does not need hospitalization," but you should contact your health care professional as soon as possible. The 2025 guideline from the AHA and the American College of Cardiology takes the same position: severe hypertension without signs of acute damage to the heart, brain, kidneys, or eyes should be evaluated and treated outside the hospital, with oral medicines started, restarted, or adjusted by a health care professional in a timely manner.

"As soon as possible" means today, including evenings and weekends. Most practices forward after hours calls to a nurse or health care professional who is on call, and many health plans run nurse advice lines. A reading that high should not wait until Monday morning. A separate article in this series covers very high readings and emergency symptoms in more detail.

Pregnancy changes the numbers. The guideline definition of severe hypertension applies to people who are not pregnant. Anyone who is pregnant should use the thresholds their obstetric care team has given them and call promptly about any high reading, headache, vision change, or pain in the upper abdomen.

Low readings have their own logic, and a separate article in this series covers what to ask about them. The general rule from MedlinePlus applies in both directions: if you are not sure what to do and you do not have an emergency symptom, call your health care professional's office.

Take a second reading before you call, and take it properly

Most surprising readings shrink on the second try. In a study of 38,260 adults with high blood pressure seen in primary care, the top number fell by a median of 8 mm Hg when the measurement was simply repeated at the same visit, and about 36 percent of the repeated readings ended up below 140/90 mm Hg. Much of that drop was regression to the mean, the statistical tendency of an unusually high value to be followed by a more typical one. The 2025 guideline notes something similar in hospitals: among people admitted with very high pressure and no symptoms, blood pressure falls on its own, without medicine, in 40 to 50 percent of cases.

So before you call, sit down, rest for 5 minutes, and take at least two more readings 1 or 2 minutes apart, following the CDC's home measurement steps: back supported, feet flat and legs uncrossed, arm resting on a table at chest height, cuff snug on bare skin, no talking. If you had caffeine, smoked, or exercised in the past 30 minutes, or if your bladder is full, mention that on the call, because each of those can push a reading up.

Write every reading down, including the first alarming one. Do not discard it because it was the highest. The nurse wants the pattern, not your best result. during the same period, resist the urge to measure ten times in a row. Repeated measuring while anxious tends to produce a scattered set of numbers that is harder to interpret, and two or three careful readings are more useful than a dozen rushed ones.

What the nurse needs, in the order they will ask

There is no official AHA or CDC script for this call. The list below is assembled from CDC and MedlinePlus advice on sharing home readings and describing symptoms, and from the substances the 2025 guideline lists as raising blood pressure. Keep a copy near your monitor.

1. 1 The numbers and the time. Give the top and bottom numbers for each reading, the time you took them, and which arm. If your monitor shows pulse, read that too. For example: "At 7:10 this morning I got 172 over 104, then 166 over 100 two minutes later, both on the left arm, pulse 78."
2. 2 Your usual. Tell the nurse what your home readings typically run. If your monitor stores readings or you keep a log, average the past week. "I usually run about 128 over 78 at home" tells the nurse far more than a single number does, because it shows how far off this one is.
3. 3 How you took it. Say whether you were seated with your back supported, had rested 5 minutes, had your arm supported at heart level with the cuff on bare skin and the right cuff size, and had avoided caffeine, exercise, and smoking for 30 minutes. If you did not, say that too. The nurse is not grading you. These details decide how much weight to put on the number.
4. 4 How you feel, and since when. List any new symptom and when it began: headache, chest pressure, shortness of breath, dizziness, vision change, trouble speaking, weakness, swelling, nausea. If you feel completely normal, say so plainly. The nurse is sorting for signs of strain on the heart, brain, and kidneys, so "I feel fine" is real information, not a throwaway line.
5. 5 Medicines today and this week. Have your bottles in front of you. Name each blood pressure medicine, the dose, and whether you took it today and at what time. Say honestly whether you missed any doses this week or ran out. If you are not sure whether you took a dose, say that rather than guessing.
6. 6 Anything new in the past week or two. The guideline's list of things that raise blood pressure includes decongestants such as phenylephrine and pseudoephedrine, pain relievers such as ibuprofen and naproxen (the class called NSAIDs), alcohol, caffeine above about 300 milligrams a day, black licorice, certain herbal products, steroid medicines, some antidepressants, and stimulants. Also mention a new prescription from any health care professional, an illness, pain, poor sleep, or unusual stress. The guideline estimates that about 20 percent of adults with hypertension regularly use nonprescription medicines that can raise blood pressure or work against treatment, and many never mention them because they do not think of them as medicine.
7. 7 Where to reach you and where you fill prescriptions. Give a callback number you will actually answer and the name and location of your pharmacy, in case the health care professional decides to send a new prescription or a change.

If you doubled a dose by mistake, say so first. You can also call the Poison Help line at 1 800 222 1222, which is staffed around the clock in more than 100 languages and advises callers before any symptoms appear.

A worked example

Suppose your usual home readings run in the low 130s over the high 70s. This evening, before supper, you get 176/108 mm Hg. You have a mild headache but nothing else.

You rest 5 minutes and repeat: 170/104, then 168/102. None of the readings reach 180/120, and you have no chest pain, shortness of breath, back pain, numbness, weakness, vision change, or speech trouble. This is an office call, made today, not tomorrow.

When the nurse answers, the report might sound like this: "I check my blood pressure at home and I usually run about 132 over 78. Tonight at 6:15 I got 176 over 108, and after resting I got 170 over 104 and 168 over 102, all on my left arm, seated, cuff on bare skin. I have a mild headache that started about an hour ago and no other symptoms. I take two blood pressure medicines (the names and doses from your bottles), and I took both this morning at 8. I did not miss any this week. I started a cold medicine with pseudoephedrine two days ago and took ibuprofen for my back yesterday and today. My pharmacy is (name and street). You can reach me at (number)."

That is about 30 seconds of talking, and it hands the nurse nearly everything needed to decide the next step. Notice what it leaves out: a request for a specific medicine change, or a report that you already took an extra pill. Adjusting doses is the health care professional's decision. The CDC's advice is not to stop a current medicine without talking with your doctor or pharmacist first, and the same caution applies to adding a dose on your own.

Why the nurse asks about your bladder and your arm

Questions about technique can feel like doubt. They are really a way of sizing up how much of the number is blood pressure and how much is measurement. A 2017 systematic review of 328 studies catalogued 29 sources of error in blood pressure measurement and found that many are large enough to move a reading across a treatment threshold. Reported average effects on the top number included a full bladder raising it by roughly 4 to 33 mm Hg, talking during the reading by 4 to 19, an arm held below heart level by about 4 to 23, too little rest beforehand by 4 to 12, legs crossed at the knee by about 3 to 15, a cuff that is too small by 2 to 11, and recent caffeine by 3 to 14. Cold exposure raised it by 5 to 32.

Stack two or three of those on top of a genuinely high day, and 150 can look like 175. That is why a nurse who hears "I took it standing in the kitchen right after climbing the stairs" will often ask you to sit, rest, and call back with fresh numbers rather than escalating. It is also why your report of your usual average is so helpful. A reading of 165/95 means something different in someone who usually runs 118/72 than in someone whose home average has sat at 158/92 for a month.

The AHA recommends an automatic upper arm cuff monitor and considers wrist and finger devices less reliable, so mention which kind you have. Bring the monitor to your next appointment so the office can check your technique and compare your device with theirs. Home monitors drift, and one that reads consistently high or low changes how every future call should be interpreted.

What to expect after you call

Office nurses and nurse advice lines generally work from the reading, your symptoms, and your medicines, then choose from a short menu of responses. Knowing the menu in advance makes the call less stressful.

1. 1 Recheck and call back. If your readings are higher than usual but well under 180/120 mm Hg and you feel well, the nurse may ask you to repeat readings over the next day or two and report the average. This is standard practice, not a brush off. Under current guidelines, treatment decisions rest on the average of repeated readings, not on a single value, however startling.
2. 2 A same day or next day visit. Persistent readings well above your usual, especially with mild symptoms, often earn an office visit where the pressure can be measured with clinic equipment and the health care professional can examine you.
3. 3 A medicine adjustment by the health care professional. This is what the 2025 guideline expects for severe hypertension without organ damage: oral medicine started, restarted, or increased in a timely way, usually without a hospital stay and without trying to force the pressure down quickly. If your health care professional makes a change by phone, ask them to repeat the instruction, write it down, and read it back to confirm.
4. 4 Go to the emergency department or call 911. The nurse will direct you there if your symptoms or history point to acute strain on an organ. If the advice is to call 911, do that rather than driving yourself.

Before the call ends, ask four things: when you should recheck, what reading or symptom should prompt another call, whom to call if that happens after hours, and whether someone from the office will call you back and roughly when. Write the answers down. If you hang up and realize you did not understand the instructions, call again. A second call that prevents a mistake is never a bother.

If the practice is closed, your call is usually forwarded to a nurse or health care professional who is on call for the clinic. Many health plans also run nurse advice lines, and the number is often printed on the back of the insurance card. These lines typically ask about the reading, your symptoms, and your medicines, then tell you whether to recheck, come in, or go to the emergency department.

Set yourself up before the next concerning reading

The easiest call is the one you prepared for at a routine visit. Ask your health care professional two questions and write the answers on your medicine list or tape them near your monitor: "At what home reading do you want me to call you?" and "At what reading, or with which symptoms, do you want me to go to the emergency department?" The answers vary from person to person and depend on your history, so there is no substitute for hearing them from the health care professional who knows your chart.

At the same visit, ask what to do about a missed dose, and record that answer too. A nurse on the phone at 9 p.m. would much rather hear "my health care professional told me what to do if I miss a dose, and I did that" than have to work it out blind.

Keep a current medicine list with doses, timing, the prescribing health care professional, and every nonprescription drug, vitamin, and supplement you take. Keep your monitor's memory or a written log so you can give a real average rather than a guess. A separate article in this series covers how to build an emergency contact card that holds much of this information in one place. Store the office number, the after hours number, and your health plan's nurse line in your phone under a name you will find quickly, because the moment you need them is not the moment to go looking.