One blood pressure reading can mislead you, so learn to read your numbers

Key takeaways

• In 2021–2023, about 23% of U.S. adults ages 18 to 39 had high blood pressure, yet only about 27% of them knew it and fewer than 5% had it under control¹.
• The 2025 AHA/ACC guideline kept 130/80 as the line for high blood pressure, set a goal below 130/80 for most adults, and uses a risk calculator called PREVENT to decide when stage 1 calls for medicine¹²⁴.
• A cuff placed over a sleeve can add 10 to 40 points to a reading, and the U.S. Preventive Services Task Force says to confirm a high office reading outside the clinic before treatment starts⁶⁸.
• In the SPRINT trial, aiming for a top number under 120 instead of 140 prevented about 16 heart and stroke events and 11 deaths per 1,000 high-risk adults over about three years, while about 22 more per 1,000 had a serious treatment-related side effect, by our math¹⁰¹¹¹².
• A reading above 180/120 with chest pain, shortness of breath, numbness, weakness, vision changes or trouble speaking means call 911, the American Heart Association says¹⁴.

From August 2021 to August 2023, the CDC’s National Center for Health Statistics measured the blood pressure of a national sample of Americans in mobile exam centers¹. Nearly half of adults, 47.7%, had high blood pressure, defined as 130/80 or higher or taking medicine for it¹.

The most striking numbers came from young adults. About 23% of people ages 18 to 39 had high blood pressure¹. Only about 27% of them knew it, and just 4.5% had it under control¹. By our math, that’s about 1 in 22.

Among adults 60 and older, about 72% had high blood pressure¹. Awareness rose with age too, but even then fewer than 3 in 10 had it controlled¹.

The 2025 national guideline calls for screening every adult². Below, we cover how to read the result, what treatment gains and costs, and when a reading is an emergency.

Two numbers: the push of each heartbeat and the pressure between beats

The top number, systolic pressure, is the peak force in your arteries as your heart squeezes. The bottom number, diastolic pressure, is the pressure that remains while your heart relaxes and refills. Both are measured in millimeters of mercury, written mm Hg.

Your large arteries act like a cushion that stretches with each beat. Over the years, they tend to stiffen.

A small 1992 study of 18 people around age 58 shows what that does⁵. Those with a high top number and a normal bottom number had much stiffer aortas, the body’s main artery⁵. In a stiff artery, the pressure wave from each heartbeat travels faster and bounces back sooner, arriving while the heart is still pushing and raising the peak⁵. Doctors call that pattern isolated systolic hypertension.

Either number can put you in a higher category². This is how the national numbers break down by age.

Age group, 2021–2023	Have high blood pressure	Of those, know it	Of those, under control
18 to 39	23.4%	27.2%	4.5%
40 to 59	52.5%	56.7%	18.1%
60 and older	71.6%	73.7%	29.2%

Source: CDC’s National Center for Health Statistics; “under control” means below 130/80¹. Overall awareness, treatment and control didn’t change significantly from 2017–early 2020, and the share with high blood pressure held about steady¹.

The 2025 guideline kept the 130/80 line and changed who gets medicine

On August 14, 2025, the American Heart Association (AHA), the American College of Cardiology (ACC) and 11 other professional groups published a new high blood pressure guideline²³⁴. It keeps 130/80 as the line for high blood pressure, the same line the 2017 guideline drew¹². The four categories²:

• Normal: top number under 120 and bottom under 80.
• Elevated: top 120 to 129 and bottom under 80.
• Stage 1 hypertension: top 130 to 139 or bottom 80 to 89.
• Stage 2 hypertension: top 140 or higher or bottom 90 or higher.

The goal for adults is below 130/80, with special considerations for people in nursing care, people with limited life expectancy and pregnant people².

What changed is how the decision to start medicine gets made. The guideline now uses PREVENT, a newer calculator built from recent data on a more diverse population, to estimate 10-year risk of heart disease, including heart attack, stroke and heart failure⁴. The older pooled cohort equations covered only artery-clogging disease and left heart failure out⁴.

The decision rules work like this²:

• Average readings of 140/90 or higher: medicine plus lifestyle change.
• 130/80 or higher with heart disease, a past stroke, diabetes, chronic kidney disease or a PREVENT risk of 7.5% or more: medicine plus lifestyle change.
• 130/80 or higher with lower risk: three to six months of lifestyle change first, then medicine if the average stays at 130/80 or above.
• Stage 2: two medicines from different families, preferably combined in a single pill.

Two other points stand out. The guideline recommends keeping the top number below 130 to help prevent mild cognitive impairment, an early stage of memory and thinking problems⁴. And it advises avoiding alcohol, or limiting it if you drink⁴.

One reading can fool you in either direction

The U.S. Preventive Services Task Force (USPSTF), an independent panel that grades preventive care, gives blood pressure screening its top grade, A, in its 2021 statement⁶. It recommends yearly checks at 40 and older or for people at higher risk, and every three to five years for lower-risk adults 18 to 39 with a prior normal reading⁶.

The Task Force adds a step many people miss: confirm a high office reading outside the clinic before treatment begins⁶. Its evidence review of 52 studies found that office-only measurement led to misdiagnosis⁷.

Two patterns explain why⁶:

• White coat hypertension: high in the office, normal elsewhere. International studies put it at about 8% of people.
• Masked hypertension: normal in the office, high elsewhere. It runs about 14% in international studies, and one U.S. study estimated 12.3%.

The gold standard is ambulatory monitoring: you wear a cuff for 12 to 24 hours, and it inflates on its own every 20 to 30 minutes⁶. Home readings with a validated cuff are an acceptable alternative⁶.

Writing in JAMA Network Open about the 2021 statement, two editorialists warned that the two-step approach could widen racial and ethnic gaps, since home readings can be a luxury without insurance coverage⁷. Task Force vice chair Michael Barry suggested pharmacies as an option for people without a home monitor⁷.

The office reading itself can also be off. The American Medical Association (AMA) and Johns Hopkins University list how much common mistakes can push a reading up⁸:

What happens at the visit	How much it can raise the reading	What you can say
Cuff goes over your sleeve	10 to 40 points8	“Can I roll up my sleeve or take my arm out?”
You’re talking or answering questions	10 to 15 points8	“Can we talk after the reading?”
You haven’t used the restroom	10 to 15 points8	“May I use the restroom first?”
Your arm hangs unsupported	About 10 points8	“Can my arm rest on the table at heart level?”
Back or feet unsupported, such as on an exam table	5 to 10 points each8	“Could I sit in a chair with my feet flat?”
Legs crossed	2 to 8 points8	Uncross them before the cuff inflates
Cuff too small for your arm	2 to 10 points9	“Is this the right cuff size for me?”

A federal Million Hearts version gives slightly different estimates, so treat these as rough ranges⁸⁹.

What treatment buys, and costs, per 1,000 people

The clearest test of how far to lower blood pressure is SPRINT, a trial funded by the National Institutes of Health¹⁰. It enrolled 9,361 adults whose top number was 130 or higher and who had a higher risk of heart disease, but not diabetes¹⁰.

Half were treated to a top number under 120 and half to under 140¹⁰. The trial was stopped early, on August 20, 2015, because the benefit was clear¹⁰¹². After one year, average readings were about 121 in the intensive group and 136 in the standard group¹⁰.

Heart attacks and other acute heart problems, strokes, heart failure and heart deaths, counted together, struck 1.65% of the intensive group each year and 2.19% of the standard group¹⁰. Deaths from any cause were also lower¹⁰. The intensive group used drugs from about three families on average, compared with two¹².

The benefits came with costs. Fainting, very low blood pressure, abnormal blood salts and sudden kidney injury were more common with intensive treatment¹⁰¹¹. Injurious falls were not¹¹.

This guide covers what that means per 1,000 people over the trial’s median of 3.26 years, by our math from the trial’s figures¹¹¹²:

Per 1,000 high-risk adults treated to under 120 instead of under 140	About how many
Fewer major heart and stroke events	16
Fewer deaths from any cause	11
More people with a serious side effect linked to treatment	22

Two limits matter. SPRINT left out people with diabetes and people living in nursing homes or assisted living¹⁰¹¹. A commentary published alongside it cautioned that the benefit might not carry over to the very old or to people with diabetes¹¹.

So SPRINT doesn’t say everyone should aim for 120. For some higher-risk adults, more treatment buys real protection along with real side effects, a trade-off to weigh with your clinician. Our article on absolute risk shows how.

The main medicine families, and what each can do

The 2025 guideline names four first-line families³:

• ACE inhibitors, such as lisinopril and enalapril. They cause a cough in up to 20% of people, can raise potassium, and can cause angioedema, a sudden swelling of the face or throat¹³.
• ARBs, such as losartan and valsartan. They can cause dizziness and raise potassium. Angioedema is rarer than with ACE inhibitors¹³.
• Calcium channel blockers of the long-acting dihydropyridine type, such as amlodipine. They can cause ankle swelling, flushing, headache and dizziness¹³.
• Thiazide-type diuretics, such as hydrochlorothiazide and chlorthalidone. They can lower potassium and magnesium, raise uric acid and cause sexual problems in men¹³.

Both ACE inhibitors and ARBs can seriously harm a developing baby, so tell your clinician if you’re pregnant or planning to be¹³. These side-effect lists come from the Merck Manual, a medical reference published by the drugmaker Merck¹³.

Beta-blockers dropped off the first-line list for uncomplicated high blood pressure. U.S. Pharmacist’s summary of the guideline says they prevent stroke less well and carry more side effects than the four main families³. They’re still used for hard-to-control pressure or specific medical reasons³.

Doctors often pair drugs whose effects balance each other. An ACE inhibitor plus a thiazide, for example, tends to even out potassium³. If pressure stays above goal, adding a second family is usually preferred over pushing one drug to its highest dose, which can raise side effects without much extra benefit³. The guideline suggests rechecking about a month after starting³.

If a medicine bothers you, say so. There are often several alternatives. But don’t stop or skip it on your own: the AHA warns against stopping medicine based on home readings without your clinician¹⁴, and some drugs, such as clonidine, can cause rebound high blood pressure if stopped suddenly¹³.

Where natural approaches fit in the guideline

Many natural-health readers would rather fix the cause than take a pill for life. The guideline shares more of that instinct than its reputation suggests.

Lifestyle change is recommended for every adult, at every stage²³. For lower-risk people in stage 1, the guideline asks for three to six months of habits before any medicine². Our companion article on blood pressure habits shows what each change is worth in points.

When medicine is needed, it works alongside those habits rather than replacing them³.

Your questions deserve straight answers, too. Ask what your 10-year risk is, how many points a medicine is expected to lower your pressure, which side effects to watch for, and what would make it reasonable to adjust the plan later.

Read your numbers: a chart for your next reading

This chart is our own summary of the guideline and AHA advice. Use your average, not a single reading, except for the last two rows.

Your reading	2025 category	What guidelines suggest next	Call 911?
Under 120 and under 80	Normal	Keep healthy habits; recheck every 3 to 5 years if 18 to 39 and low risk, yearly if 40 or older6	No
120 to 129 and under 80	Elevated	Lifestyle change2	No
130 to 139, or 80 to 89	Stage 1	Confirm outside the office6; ask for your PREVENT risk; lower risk means 3 to 6 months of habits first2	No
140 or higher, or 90 or higher	Stage 2	Medicine plus habits, often two drugs in one pill2	No, unless symptoms
Over 180/120, no symptoms	Severe	Wait a minute and recheck; if still high, contact your clinician right away14	No
Over 180/120 with symptoms below	Possible emergency	Get help immediately14	Yes

When a high reading is an emergency

Very high pressure without symptoms is serious but usually not a 911 call. For nonpregnant adults above 180/120 with no sign of new organ damage, the guideline calls for prompt treatment through a regular clinic². The AHA’s advice: recheck after at least a minute, and contact your clinician right away if it’s still that high¹⁴.

Doctors call very high pressure with signs of new organ damage a hypertensive emergency. The symptoms below can be warning signs.

Pregnancy has its own rules. The 2025 guideline names high blood pressure before and after delivery, preeclampsia and eclampsia as specific risks and gives separate advice for them⁴. If you’re pregnant or recently gave birth, ask your prenatal clinician which readings and symptoms should prompt an urgent call.

What the evidence shows

Claim	Evidence rating	What it rests on
Lowering high blood pressure prevents heart attacks, strokes and deaths	Strong evidence	SPRINT and the 2025 guideline21012
A target under 120 helps high-risk adults without diabetes more than under 140	Strong evidence, with more side effects	SPRINT; benefits and harms in absolute numbers101112
Office readings alone can misclassify people	Strong evidence	Task Force review of 52 studies; white coat and masked patterns67
Beta-blockers prevent strokes as well as the four main families in uncomplicated high blood pressure	Evidence says no, or unsafe	Removed from first-line use; weaker stroke prevention3
Smartwatches and other cuffless devices measure blood pressure reliably	Not enough evidence	The guideline advises against relying on them2

Questions readers ask

The bottom line

Blood pressure is two numbers, four categories and a lot of fine print. The 2025 guideline kept 130/80 as the line, aimed for below that, and now uses your overall risk to decide when stage 1 needs medicine. One office reading isn’t enough to start treatment: confirm it at home or with a wearable ambulatory monitor, and make sure it was taken correctly.

Treatment works, and it has costs you can count. Ask for the numbers per 1,000 people, talk through side effects before you start or stop anything, and call 911 for a reading above 180/120 with chest pain, breathlessness, weakness, vision changes or trouble speaking.

Keep exploring: nighttime blood pressure dipping.

Related reading

• Habits can lower blood pressure like a pill, and a home cuff keeps score
• A 22% risk cut can mean helping 2 or 3 people in 1,000
• Side effects are real, and so are the ones fear creates
• The symptoms that mean call 911 now
• Your family tree and free risk calculators can show you where to start

Sources

1. Fryar CD, Kit B, Carroll MD, Afful J. “Hypertension Prevalence, Awareness, Treatment, and Control Among Adults Age 18 and Older: United States, August 2021–August 2023.” NCHS Data Brief No. 511, CDC, October 23, 2024. cdc.gov
2. American Heart Association. “Top Things to Know: 2025 High Blood Pressure Guideline” (on Jones DW, Ferdinand KC, Taler SJ, et al., Circulation and Hypertension, August 14, 2025). AHA Professional Heart Daily. professional.heart.org
3. Mahvan T, Adkison M, Mooney S. “ACC/AHA Hypertension Guideline Update.” U.S. Pharmacist, 2026;51(3):29–32, March 12, 2026. uspharmacist.com
4. HCPLive. “AHA, ACC Release New Guidelines for High Blood Pressure to Reduce CVD Risk.” August 14, 2025. hcplive.com
5. Nichols WW, Nicolini FA, Pepine CJ. “Determinants of isolated systolic hypertension in the elderly.” Journal of Hypertension Supplement, 1992;10(6):S73–77 (abstract via QxMD Read). pubmed.ncbi.nlm.nih.gov
6. U.S. Preventive Services Task Force. “Hypertension in Adults: Screening.” Final recommendation statement, April 27, 2021. uspreventiveservicestaskforce.org
7. TCTMD. “USPSTF Reaffirms Earlier Stance on Hypertension Screening in Adults.” April 28, 2021. tctmd.com
8. American Medical Association and Johns Hopkins University. “BP Technique Quick Check.” 2015. ama-assn.org
9. Million Hearts, U.S. Department of Health and Human Services. “7 Simple Tips to Get an Accurate Blood Pressure Reading” (adapted from AMA and Johns Hopkins materials). millionhearts.hhs.gov
10. SPRINT Research Group; Wright JT Jr, Williamson JD, Whelton PK, et al. “A Randomized Trial of Intensive versus Standard Blood-Pressure Control.” New England Journal of Medicine, 2015;373(22) (abstract reproduced by Infomed, Cuban Ministry of Public Health). especialidades.sld.cu
11. ACP Internist Weekly. Summary of the SPRINT trial report and editorials (NEJM, published online November 9, 2015). American College of Physicians, November 17, 2015. immattersacp.org
12. Ferrini M. SPRINT trial summary (slides). European Society of Cardiology, Council for Cardiology Practice. escardio.org
13. Merck Manual Consumer Version. “Antihypertensive Medications” (table). Merck & Co., 2026. merckmanuals.com
14. American Heart Association. “Monitoring Your Blood Pressure at Home.” AHA (heart.org content), accessed October 2026. recipes.heart.org