Apple Watch Biological Age App Guide: Set Up My Bio Age

My Bio Age uses measurements available through Apple Health to calculate a weekly Index and daily wellness scores on your iPhone. The Apple Watch companion displays results received from the phone. You do not need a My Bio Age account to begin.

1. Set up the iPhone app

1. Download My Bio Age free from the App Store on your iPhone.
2. Open the app and review the Apple Health permission sheet.
3. Allow the categories you want it to use.
4. Wait for the initial import and longer history backfill to finish.

A permission sheet does not guarantee every category has records. If a score is missing, inspect the app’s data coverage information and the corresponding category in Apple Health before repeating setup.

2. Install the watch companion

Open Apple’s Watch app on the paired iPhone and check whether My Bio Age is installed on the watch. Install it if it appears among the available apps. Keep both devices connected and use compatible app versions.

3. Refresh the displayed scores

Open My Bio Age on iPhone and let it finish refreshing. Then open My Bio Age on the watch while the phone is reachable. The watch requests the latest scores and retains the last values it receives.

If you later leave the phone behind, those cached values can remain visible. They are not newly calculated watch-only scores. The watch dashboard includes freshness information to help you tell the difference.

4. Read the Index and daily metrics separately

The MyBioAge Index™ uses complete Monday-to-Sunday weeks. Recovery, Training Load, Stress Resilience and Circadian Alignment are separate daily views. A new HRV reading does not mean the latest stored weekly Index must change immediately.

If the watch still looks out of date

• Check whether the phone itself shows fresh data.
• Keep the watch app open with the phone reachable.
• Check connection status and reopen both apps if needed.
• Confirm that the installed watch app is the current version.

For missing source records, review Apple Health before troubleshooting watch transfer. For questions about the number itself, use the iPhone’s detail views. The Index is a wellness estimate, not a clinical biological age test or a diagnosis.

For missing source measurements, follow the Apple Health data troubleshooting guide.

Ready to set up your iPhone dashboard and Apple Watch companion? Download My Bio Age free on the App Store. The iPhone app is completely free, with no in-app purchases, subscription or account required. Your health data is processed privately on your iPhone.