The short version
P247 uses your maximum heart rate to work out your training load and fitness. If you don't set one, it uses an estimate or a default. Setting your own number makes your load and fitness more accurate, and when you save it P247 rescores your past workouts in the background.
Why your maximum heart rate matters
Your maximum heart rate is the highest heart rate you can reach in an all-out effort. P247 measures how hard a session was against it, so a number that's too high or too low skews your training load and fitness.
P247 picks the number it uses in this order:
- A maximum heart rate you've set yourself.
- An age-based estimate from your date of birth (the Tanaka formula, 208 − 0.7 × your age), if you've added one.
- A default of 170 bpm.
The age-based estimate works for ages 18 to 100. It's a population average, so it can sit well above or below your real maximum.
How to set it in the app
In the latest version of the app, you can set your maximum heart rate yourself. If you don't see the card described below, update P247 from the App Store.
- In the P247 app, open Settings, then go to You and your body and choose Heart rate, zones and HRV.
- Open the Heart screen and find Max heart rate used for load and fitness. It shows your number and where it came from: Default (170 bpm), Estimated from your age or Set by you.
- Tap Set your max heart rate, enter your number in bpm, then tap Save max heart rate.
- Don't know your number? Use Add date of birth for an estimate and tap Save date of birth to get an age-based estimate.
Your max heart rate is saved to your account with Save max heart rate. The button at the top right of the screen, Saved on iPhone, is for the zone and HRV settings on the phone only. It doesn't save your max heart rate to your account.
If a sport's zones use the threshold method, saving a max heart rate can switch that sport's zones from threshold-based to maximum-based. The app asks you to confirm first, and it only changes that sport's zones. Your other sports and daily settings stay as they are.
The screen has a sport picker (Running or Cycling). Your load and fitness use the highest maximum you've saved across the sports. Your max heart rate and date of birth are saved to your P247 account. The sport zone and HRV controls further down the screen stay on your iPhone only.
The Heart screen also sets up in-app heart rate zones, which are separate. Zones are off until you turn them on for a sport, and they only drive the zone charts and zone times in the app on your phone. Training load and fitness work without them. The Scan running workouts button scans a year of your Apple Health workouts and suggests a maximum heart rate for those zones: the highest rate you held for a complete minute, ignoring short spikes. Nothing changes until you accept it and save. It doesn't change the Max heart rate used for load and fitness above, which is what your training load and fitness follow.
Already saved a max on your iPhone in an earlier version of the app? After you update, the Max heart rate used for load and fitness card can ask Use the max heart rate saved on this iPhone? and shows your highest saved maximum from your enabled sports, for example "Running · 175 bpm", labelled Accepted workout estimate or Entered manually. Tap Use 175 bpm (your number will differ) to save it to your account as a value you chose, and your past workouts, load and fitness are rescored in the background. It's never imported automatically. If you tap Not now, the offer stays hidden for that account.
In the latest version you may also see a card on the Today screen that says Make your heart rate personal. It links straight to this screen. You can dismiss it and it stays dismissed.
How to find your maximum heart rate
Use the highest heart rate from a recent all-out effort or race. Two good ways to find yours:
- A recent all-out effort or race finish. Look at the highest heart rate you saw, ideally from a hard race or a very hard session where you gave everything at the end.
- A supervised test. A lab, clinic or qualified coach can run a structured test and measure it for you.
A chest strap is ideal, because wrist sensors can spike, especially in cold weather, with a loose strap or during strength work. A single reading far above everything else you've seen is worth doubting.
Otherwise, add your date of birth for an age-based estimate and use that until you have a real number. You can change it later.
Not medical advice. All-out efforts are hard on the body. If you have a heart condition, any symptoms or you're unsure, talk to a doctor before testing your maximum heart rate.
What happens after you save it
After you save, the screen shows "Saved. Recalculation is in progress for past workouts, training load and fitness. Your numbers may change." P247 rescores your past workouts, training load and fitness in the background, and it can take a short time to finish. That's expected: the same sessions are now being measured against a more accurate maximum.
Resting heart rate
P247 takes your resting heart rate from a rolling 30-day median of your morning readings, so one unusual morning doesn't move it much. Until it has at least seven days of readings, it uses a default value.
Threshold heart rate
Threshold heart rate is the heart rate you can hold at a hard, steady effort. P247 uses the threshold you've saved, or works one out if you haven't saved one.
You can set it on the web: sign in at app.p247.io/athlete and open the Thresholds tab in the top tab bar. Use Preview zones, then Save threshold. It's for running and cycling threshold heart rate only, and there's no maximum heart rate field there.
Related
This page is general information to help you use P247. It isn't medical advice, diagnosis or treatment. For injury, illness or any health concern, speak to a qualified health professional.
P247 turns your Apple Health data into a daily brief and a weekly report that tells you what to change next week. Available now on the App Store. Your first weekly report is free.
