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Blood pressure basics, explained plainly

These blood pressure guides explain what systolic and diastolic measure, how to read a BP chart, how to get an accurate reading at home, and more: the fundamentals behind each number CardiLog logs.

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Blood Pressure Chart: Normal, Elevated, High & Crisis Ranges

Under the AHA/ACC guideline, any adult blood pressure reading lands in one of four categories (normal, elevated, stage 1 or stage 2 hypertension), with a separate severe range above 180/120. Here's what each range on the chart means, and why a doctor in Europe or the UK might label the same numbers differently.

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Normal Blood Pressure by Age: What the Numbers Look Like Over Time

Current guidelines don't set a different "normal" blood pressure for each age group. What does change with age is the typical reading: arteries stiffen, systolic pressure keeps climbing, and diastolic pressure tends to level off and then drop after about 50 to 60.

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Understanding Your Blood Pressure Reading: Systolic, Diastolic & Pulse

A blood pressure monitor shows three numbers (systolic, diastolic and pulse), usually written as "120/80, pulse 72". Here's what each one measures, how to read them together, and why the top number isn't the whole story.

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What Is Systolic Blood Pressure?

Systolic blood pressure is the top number in a reading. It measures the pressure in your arteries when your heart contracts and pushes blood out, and for people over 50 it's the number that says most about heart disease risk.

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What Is Diastolic Blood Pressure?

Diastolic blood pressure is the bottom number in a reading. It measures the pressure in your arteries between heartbeats, while your heart relaxes and refills. On its own it can move a reading into a higher stage, so it's more than a supporting figure.

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What Is Pulse Pressure and Why It Matters

Pulse pressure is the gap between your systolic and diastolic numbers: systolic minus diastolic. For a 120/80 reading, that's a pulse pressure of 40. Most people never look at it, but it can add useful context to your readings, especially as you get older.

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What Is Mean Arterial Pressure (MAP)?

Mean arterial pressure (MAP) is the average pressure in your arteries across a full heartbeat. It's weighted toward diastolic, because at rest your heart spends more time relaxing between beats than contracting. Clinicians use it as a single number for whether blood is reaching your organs at enough pressure.

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How to Take an Accurate Blood Pressure Measurement at Home

A single slip, like talking mid-reading, a cuff over your sleeve or a full bladder, can push a reading up by 10 mmHg or more. Here's how to measure blood pressure at home the way guidelines recommend, so you get a number you can trust.

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Free Blood Pressure Log: Printable PDF vs. a Digital Log

A paper blood pressure log is better than no log at all. It's also likely to get lost or forgotten, and hard to turn into a trend your doctor can use. Here's what a good log needs, whether you keep it on paper or in an app.

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Best Time to Take Blood Pressure Medication: Morning or Night?

For some years, bedtime dosing of blood pressure medication looked like a simple way to cut heart attacks and strokes. Larger, more careful trials have since found no difference between morning and evening. The practical answer: take your pills at the time you're least likely to forget, and check any change with your prescriber first.

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Home Blood Pressure Average Calculator (NICE 7-Day Method)

Doctors judge home blood pressure by the average of a week of readings, not by one number. This home blood pressure average calculator follows the method NICE sets out for diagnosis: two readings morning and evening for up to 7 days, with the first day left out.

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Why Is My Blood Pressure Higher in the Morning?

Blood pressure follows a daily rhythm, and part of it is a rise around the time you wake. Here's why blood pressure is higher in the morning, when a high morning reading deserves a closer look, and how to measure in the morning so the number means something.

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Can Your iPhone or Apple Watch Measure Blood Pressure?

An iPhone can't measure blood pressure on its own, and Apple Watch doesn't give a reading either. Here's what each device can and can't do, how to log readings in Apple's Health app, and where a validated cuff fits in.

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Irregular Heartbeat Symbol on a Blood Pressure Monitor: What It Means

The irregular heartbeat symbol on a blood pressure monitor means the cuff noticed uneven timing between beats during that reading. It isn't a diagnosis, and arm movement can set it off, but if it keeps appearing it's worth showing your doctor. Here's what each part of that means.

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How Long to Wait Before Taking Your Blood Pressure

Coffee, a workout, a meal, a cigarette or a drink can all move your blood pressure for a while. Here's how long to wait before taking your blood pressure after each one, what the guidelines set as the minimum, and why some effects last longer than that.

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Blood Pressure Cuff Size Chart: How to Measure Your Arm

A cuff that's the wrong size for your arm can push a reading up or down by several points, or far more. This blood pressure cuff size chart shows which cuff fits which arm, how to measure your arm in a minute with a tape measure, and what to do if standard cuffs don't fit.

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How to Export Blood Pressure Data from Apple Health

Your monitor's app, your Apple Watch or your own typing may all have put blood pressure readings into Apple Health. Getting them back out, as a file your doctor can read, isn't obvious. Here are the three ways to export blood pressure data from Apple Health, what each one gives you, and which to use for a doctor's appointment.

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How to Check If Your Blood Pressure Monitor Is Accurate

Studies of home monitors brought in by their owners have found that many read differently from a careful clinic measurement. Here's how to check if your blood pressure monitor is accurate, using the test the American Medical Association publishes, what difference is acceptable, and how often to check again.

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Wrist vs. Upper-Arm Blood Pressure Monitors: Which Is More Accurate?

Wrist blood pressure monitors are small and quick to put on, so they're tempting. But guidelines recommend upper-arm monitors for home use, and wrist readings depend heavily on how you hold your arm. Here's what the evidence says about wrist vs upper-arm blood pressure monitors, and how to get a usable reading if a wrist monitor is your only option.

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Best Blood Pressure Apps for iPhone in 2026

We looked at six iPhone apps people actually use to track blood pressure: one we make, four built by monitor makers or for Bluetooth cuffs, and the Health app that's already on your phone. Here's what each one does well, where it falls short, and who it suits.

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Best Blood Pressure Apps for Seniors and Caregivers

For seniors, the best blood pressure app is the one they'll use: big enough to read, little to type, and quick to share with you or their doctor. We compared six iPhone apps on exactly those points.

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Best Home Blood Pressure Monitors (Validated) for 2026

Plenty of home blood pressure monitors have never passed an independent accuracy test. All the monitors below are upper-arm models listed for home use on STRIDE BP, an international list of validated devices, and we checked each entry on the list itself.