Estimate Heart-Rate Recovery From Your Workout Cooldown

My Bio Age's daily Recovery score, Recovery Capacity, needs at least one heart-rate recovery reading from the last 14 days. Those readings come from Apple Health, and after many sessions there simply isn't one. Recovery can then stay blank even when your sleep, HRV and resting heart rate are all available.

Coming in My Bio Age 1.0.23, which is in development as of October 2026, is an optional way to fill some of those gaps: an estimate of the one-minute heart-rate drop, made from your own workout records. This is a preview, and details may change during testing. Here is how it works, and where its limits are.

What the setting does

In versions with “Estimate from workout cooldowns”, starting with 1.0.23, open Settings in My Bio Age, find Heart-rate recovery and turn the setting on. It is off by default. When you turn it on, the app asks Apple Health for permission to read your Workouts and Heart Rate. It adds no write permission.

The setting looks for exercise followed by a separate workout of the Cooldown type, which Apple's HealthKit documentation describes as gentle stretching and mobility work after a harder session. From that pair, the app measures how far your heart rate fell in the first minute after the exercise ended.

• Apple Health comes first. On any day that already has a heart-rate recovery reading in Apple Health, the app uses Apple's value for the whole day and sets the estimate aside.
• Estimates are labelled. They are calculated on your iPhone, identified as estimates in the app and never written to Apple Health.
• Turning it off removes them, along with their saved results, and recalculates your scores. Your Apple Health records are untouched.

How to log a session it can use

The estimate uses only records that already exist. It never starts a workout or fills in missing readings.

1. Record your exercise in the Workout app on Apple Watch, or in another app that saves workouts to Apple Health.
2. As soon as you stop, end that workout and start a separate Cooldown workout. It must run at least through the first minute after the exercise ended. A five-minute cooldown is fine; only the one-minute drop is used.
3. Keep the times accurate: the measurement starts at the recorded end of your exercise.
4. If you add sessions afterwards with Fitness's Log a Workout, you can set the type, start time and duration, but logging cannot add heart-rate readings after the event. Such sessions count only if background readings cover that minute.
5. Keep your watch snug. Apple's heart-rate guide notes that the watch cannot always get a reliable reading, and background measurement varies by model and settings.

Recording the cooldown live helps when background readings are sparse. Apple's technical overview of heart-rate measurement says the watch aims to report a heart rate every five seconds during a Workout app session, subject to signal quality.

How the estimate is calculated

The calculation is deliberately simple: your heart rate at the recorded end of the exercise, minus your heart rate 60 seconds later. If it was 150 bpm when you stopped and 128 bpm a minute later, the estimate is 22 bpm. Before a number is accepted, the session must pass several checks:

• Timing. The cooldown must begin within five minutes of the exercise ending. Up to one minute of overlap is allowed, because manually entered times may be rounded to the minute.
• Coverage. The readings must form one continuous stream from a single device: typically at least four readings across the minute, readings within about 10 seconds of the moment you stopped and of the one-minute mark, and no gap longer than 20 seconds.
• Observed, not modelled. If no reading falls exactly on a mark, the app interpolates between the readings either side, each within about 10 seconds; it never extrapolates beyond them. If your heart rate stayed flat or rose, that is recorded as observed, as a drop of zero or less.
• Exclusions. Sessions with a sauna, ice bath or other Preparation and Recovery workout that overlaps the first minute, ambiguous overlapping workouts, another workout during the first minute and manually entered heart-rate values are left out. Mind-and-body, flexibility and “other” workouts don't count as the exercise.

This is not Apple's measure. Apple's definition of one-minute recovery starts from your peak exercise heart rate, and the watch's own Cardio Recovery is modelled to predict recovery after a standardised submaximal effort. My Bio Age's estimate is a plain observed drop from wherever your heart rate was when you stopped. These are app quality rules, not a clinical protocol, so compare similar routines with each other, not with Apple's numbers or research cut-offs.

Where estimates appear

• HR Recovery. Estimates join your HR Recovery history. Its detail screen says when they are included, and the AI Coach is told too.
• Recovery Capacity. Estimates can count towards the daily Recovery score, which still needs a reading from the last 14 days. A successful cooldown from three weeks ago won't fill today's gap.
• The weekly Index. HR Recovery isn't a separate input to the MyBioAge Index™, but estimates can affect it, mainly through Recovery Capacity.

Below the setting, “Check cooldowns again” re-reads the last six months of records. “Check details” lists the workouts and cooldowns found, how many were measured, and why others couldn't be used, such as no matching exercise or gaps in the heart-rate recording. iOS doesn't tell apps whether read access was granted, so an empty result doesn't prove permission was denied; check access in the Health app and let your watch finish syncing.

Privacy

Every estimate is calculated on your iPhone. The setting adds no network transfer, nothing is written to Apple Health, and the check details stay on the device. Version 1.0.23 has no export or sync for HR Recovery history, and the AI Coach that reads estimates also runs on your iPhone. Our privacy policy has the details.

Using cooldown estimates well

Treat estimates as a way to keep Recovery going when Apple Health has nothing recent, not as a sharper measurement. Our guide to the one-minute heart-rate drop explains what the number means, and the Recovery Capacity guide covers the other signals in the score. For the rest of this release, see the 1.0.23 preview. If you train often, read about balancing training load and recovery.

Download My Bio Age free on the App Store to explore your existing Apple Health recovery data in the current release. The iPhone app is completely free, with no in-app purchases, subscription or account required. Health data stays on your iPhone, and the optional AI Coach runs fully on-device. The cooldown setting described here is still a preview of version 1.0.23, in development as of October 2026.

Symptoms matter more than any estimate. If you have chest pain or dizziness during or after exercise, stop and talk with your doctor. For sudden chest pain that does not go away, call emergency services. My Bio Age offers general wellness information, not medical advice, and cannot diagnose a heart condition.