High blood pressure: what the numbers mean and how to bring them down
Last updated September 3, 2026.
High blood pressure almost never causes symptoms, yet it quietly damages the heart, brain, kidneys, and eyes for years. That is what makes it dangerous: you feel fine while the pressure stiffens arteries and strains the heart. The only way to know your number is to measure it, and a single high reading in a doctor's office does not make the diagnosis.
What do the numbers mean?
A reading has two numbers: systolic (the pressure when the heart squeezes) over diastolic (between beats). US guidelines define normal as under 120/80, elevated as 120-129 over under 80, stage 1 hypertension as 130-139 or 80-89, and stage 2 as 140/90 or higher. UK and European guidelines start treatment thresholds at 140/90. The gap between systems matters less than the trend: risk climbs steadily as numbers rise. Diagnosis needs confirmed elevated readings on at least two separate occasions, ideally with home monitoring, because "white coat" readings in clinics run high for many people.
How do you measure it correctly?
Home readings beat clinic readings for the real picture. Use an automatic upper-arm cuff (wrist devices are less reliable) with the right cuff size, rest seated for 5 minutes first, feet flat, arm supported at heart level, no caffeine, exercise, or smoking in the 30 minutes before. Take two readings a minute apart, morning and evening, for 4 to 7 days, and average them, discarding the first day. An average of 135/85 or higher at home corresponds to 140/90 in the clinic. Skip measuring when you are stressed, in pain, or have a full bladder; all three push the number up.
What actually helps?
- Sodium cut: getting under about 2g of sodium (5g of salt) a day can lower systolic pressure by 5-6 points. Most sodium hides in bread, processed meats, cheese, and restaurant food, not the salt shaker.
- Exercise: 150 minutes a week of brisk walking, cycling, or swimming lowers systolic pressure by roughly 5-8 points, a real drug-sized effect.
- Weight and alcohol: each kilogram lost drops systolic pressure about a point. Keeping alcohol to one drink a day or less matters as much as any diet tweak.
- Medication when indicated: first-line choices include ACE inhibitors like lisinopril (often started at 10mg daily), calcium channel blockers like amlodipine (5mg daily), and thiazide diuretics. Many people need two agents at moderate doses rather than one at maximum.
- Potassium-rich food: bananas, potatoes, beans, and greens blunt sodium's effect, unless you have kidney disease or take drugs that raise potassium.
When is it an emergency?
A reading of 180/120 or higher with symptoms - chest pain, sudden severe headache, blurred vision, confusion, weakness on one side, or breathlessness - is a hypertensive emergency: call emergency services, do not drive yourself. The same number without any symptoms (hypertensive urgency) still needs same-day medical contact, but is usually handled with prompt medication adjustment rather than an ER visit. Do not take extra doses of someone else's blood pressure pills or double your own to force the number down. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
What a Pymander AI doctor consult looks like
Illustrative example, not a real member's messages.
Common questions
Can high blood pressure cause headaches or dizziness?
Usually no. Mild to moderate hypertension is famously symptomless, and studies have found no reliable link between everyday blood pressure levels and headaches. The exception is a hypertensive crisis (180/120 or above), where a sudden severe headache, blurred vision, or confusion signals emergency-level pressure. Routine headaches and dizziness have many more likely causes, so treat them on their own merits while still getting your pressure checked.
What is the best home blood pressure monitor?
Pick an automatic, validated, upper-arm cuff; wrist and finger devices are too sensitive to position. The right cuff size matters more than the brand: too small reads falsely high, too large reads falsely low. Measure your arm circumference and match it to the cuff range on the box. Look for validation listings (such as validatebp.org in the US). Expect to pay modestly; the basic validated models from major brands are all adequate.
Do I need medication if my blood pressure is 135/85?
It depends on your overall risk, not the number alone. At 135/85 (stage 1 range), guidelines recommend medication if you already have cardiovascular disease, diabetes, kidney disease, or a 10-year cardiovascular risk of 10% or more. Otherwise the first move is 3 to 6 months of serious lifestyle change, then reassess. This is exactly the decision to make with a clinician who can calculate your actual risk.
Which blood pressure medication has the fewest side effects?
All first-line classes are well tolerated by most people, but each has a signature annoyance. ACE inhibitors like lisinopril can cause a dry cough (about one in ten people). Amlodipine can cause ankle swelling. Thiazides can lower potassium and raise uric acid. ARBs like losartan work like ACE inhibitors without the cough and are the usual swap. If one drug bothers you, switching classes almost always solves it, so report side effects rather than quietly stopping.
How much does salt really matter?
A lot, but from hidden sources. Cutting sodium from a typical intake to under 2g a day lowers systolic pressure by about 5-6 points on average, more in salt-sensitive people. Roughly 70% of dietary sodium comes from packaged and restaurant food: bread, deli meat, pizza, soup, sauces, and cheese. Reading labels beats avoiding the shaker. The DASH eating pattern, built around this plus potassium-rich food, can deliver a combined 8-14 point drop.
Can I stop taking blood pressure medication once my numbers improve?
Sometimes, with a plan. If your pressure normalizes through weight loss, exercise, and diet change, a clinician may trial a dose reduction or withdrawal with home monitoring. Stopping on your own is the risky version: some medications (especially beta blockers and clonidine) can cause rebound spikes, and pressure typically drifts back up within weeks of stopping. Improvement earns a conversation about deprescribing, not a unilateral quit.
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