Help & guides
How to get a clean reading, what HRV, stress, energy and your Heart Score mean, and how to log and track everything else.
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How to measure your heart rate with your iPhone camera
Measure your pulse in about 45 seconds by resting a fingertip on your iPhone's rear camera and flash. Here's how to get a clean reading the first time.
Read guide →Heart rate reading failed? How to get a clean one
Most failed readings come down to pressing too hard or moving. Here's what the app checks for and how to get a reading it can trust.
Read guide →How accurate is a camera heart rate reading?
A fingertip camera reading uses the same principle as a pulse oximeter, but with a cruder sensor. Here's what it does well, where it falls short, and how to get the best from it.
Read guide →Measuring your heart rate on iPad
Most iPads have no flash, so the light has to come from the room. Here's how to measure your pulse on an iPad and get a steady reading.
Read guide →When is the best time to measure your heart rate?
For a trend you can trust, measure at the same time each day — ideally on waking, before getting out of bed. Here's why timing matters so much.
Read guide →What is PPG? How a camera reads your pulse
Photoplethysmography (PPG) measures changes in how much light your tissue absorbs as blood pulses through it. Here's how a phone camera turns that into a heart rate.
Read guide →What is heart rate variability (HRV)?
Heart rate variability is the small difference in time between one heartbeat and the next. Here's what it tells you about recovery and stress — and what it doesn't.
Read guide →RMSSD, SDNN and pNN50 explained
Three common ways to put a number on heart rate variability. What each one measures, and which one to watch day to day.
Read guide →What is a good HRV?
There's no single good HRV number. Typical adult RMSSD sits roughly between 15 and 75 ms — but your own trend matters far more than anyone else's figure.
Read guide →How the Heart Score works
The Heart Score is one 0–100 number built from four parts: resting pulse, RMSSD, SDNN and stress. Here's how it's weighted and what the bands mean.
Read guide →What does the stress level mean?
The stress index runs from 0 to 100 and is read from your beat-to-beat variation. Here's what calm, mild tension and high stress mean — and how to bring it down.
Read guide →What does the energy level mean?
Energy is a 0–100 estimate of how ready your body is for load right now, read from your pulse and variability. Here's how it's calculated.
Read guide →What is heart age?
Heart age compares your resting pulse and variability with what's typical at your age, and expresses the gap in years. An indicator of habits, not a medical assessment.
Read guide →How breathing rate is read from your pulse
Breathing leaves a trace in your pulse: beats speed up slightly as you breathe in and slow as you breathe out. Here's how the app counts breaths from it.
Read guide →What is a normal resting heart rate?
For most adults, a normal resting heart rate is 60 to 100 beats per minute, according to the American Heart Association. Here's what shifts it and how the app grades yours.
Read guide →How to lower your resting heart rate
Regular aerobic exercise, better sleep and less alcohol and caffeine are the habits most likely to bring your resting heart rate down over time.
Read guide →Target heart rate zones for exercise
The American Heart Association estimates maximum heart rate as 220 minus your age, with moderate exercise at 50–70% of it and vigorous exercise at 70–85%.
Read guide →What raises your heart rate at rest?
Caffeine, stress, poor sleep, alcohol, dehydration, heat and illness can all push your resting heart rate up. Here's what to rule out before you compare readings.
Read guide →When should a heart rate reading send you to a doctor?
An app reading can't diagnose anything. Here are the signs that mean you should contact a doctor or emergency services instead of measuring again.
Read guide →How to measure blood pressure at home and log it
Your phone's camera can't measure blood pressure — a cuff can. Here's how to take an accurate home reading, what the AHA categories are, and how to log it next to your pulse.
Read guide →Logging blood sugar: fasting and after meals
Log readings from your glucose meter as fasting or after eating, and see them next to your pulse. Here are the ADA ranges the categories are based on.
Read guide →Logging blood oxygen (SpO₂) from a pulse oximeter
A phone camera can't measure blood oxygen — a pulse oximeter can. Here's how to get a good oximeter reading and what can throw it off.
Read guide →Reading your trends — and adding mood and activity
Charts by day, week, month and year show where your pulse and HRV are heading. Adding mood and activity to each reading gives a high number its context.
Read guide →Using the health plans
Four short plans — lower blood pressure, calmer days, better sleep and a stronger heart — turn general habits into daily steps you can track with your readings.
Read guide →How to save your readings to Apple Health
Turn on Apple Health in the app's Settings and every reading's heart rate — plus its SDNN, where the recording supports one — is saved to Health. Nothing is read back.
Read guide →Add the heart rate widget to your Home Screen
Put your latest reading on your Home Screen with the widget. Here's how to add it in a few taps.
Read guide →Export a PDF health report for your doctor
Create a PDF of your readings, laid out for an appointment, and share it however you like. PDF export is part of PRO.
Read guide →Set reminders to measure and to take your medication
A daily reminder keeps your readings at the same time each day — the key to a trustworthy trend. You can add medication reminders too.
Read guide →Free vs. PRO — and how the free trial works
The free version includes 5 measurements, 7 days of history, day and week charts and RMSSD. PRO adds unlimited measurements, your full history, more HRV detail and PDF export.
Read guide →How to cancel your PRO subscription
Cancel PRO — or a free trial — from your iPhone's Settings. You keep PRO until the end of the period you've paid for.
Read guide →