Privacy Policy & Google Play Health Data Safety

Effective Date: October 17, 2026 • Package ID: com.headstrong.app

Google Play Data Safety Summary:

100% On-Device Storage: Your workout logs, body weight history, and biometric recovery metrics are stored locally on your device.
Zero Third-Party Data Sharing: HeadStrong never sells, rents, or shares your health or fitness data with advertising networks or third parties.
Instant In-App Data Deletion: You can export or permanently erase all stored data at any time inside Program → Data Safety & Privacy.

1. Health & Biometric Data We Process

When you log workouts or optionally connect your Google Pixel Watch via the Fitbit Web API (OAuth 2.0 PKCE), HeadStrong processes:

Workout & Strength Logs: Exercises, sets, repetitions, weights lifted, and Repetitions in Reserve (RIR).
Body Weight Metrics: Daily scale entries used to compute your 7-day Exponential Moving Average (EMA) and DOTS strength score.
Optional Wearable Telemetry: Heart Rate Variability (RMSSD), Resting Heart Rate (RHR), Sleep duration, Daily Steps, VO2 Max, and Active Zone Minutes (AZM) to compute your Daily Readiness Score.

2. How Your Data Is Stored & Protected

All workout sessions, custom exercises, and biometric logs are persisted locally on your device. If you authorize Fitbit Web API via OAuth 2.0 PKCE (RFC 7636), cryptographic code verifiers are held strictly in ephemeral session storage and connections occur over TLS/HTTPS directly between your device and api.fitbit.com.

3. Data Retention, Export & Permanent Deletion

In compliance with Google Play’s User Data and Account Deletion Policy, you have complete control over your data directly inside the app:

Export Backup: Navigate to Program → Data Safety & Privacy → Export My Data (JSON) to download a complete copy of your records.
Permanent Deletion: Navigate to Program → Data Safety & Privacy → Delete All My Data to permanently wipe all workout logs, biometric records, and OAuth tokens from your device.

4. Non-Medical Fitness Disclaimer

HeadStrong is a fitness and strength training tool designed for educational and workout-tracking purposes only. Readiness scores, heart rate recovery indicators, and volume landmarks do not constitute medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional before starting an intensive strength program.

5. Contact & Support

For privacy inquiries or data protection support, contact: privacy@headstrong.app