Overview
Pulse Link: Heart Rate BLE ("the app") is developed by Humble Mars LTD. Your privacy is important to us. This policy explains what data the app accesses, how it is used, and how it is protected.
In short: all data stays on your devices. There are no accounts, no analytics, no cloud storage, and no data shared with third parties.
What We Don't Do
- No user accounts or registration
- No cloud storage or server-side processing
- No third-party SDKs or services
- No advertising or ad tracking
- No data shared with or sold to third parties
- No cross-app or cross-site tracking
Data Accessed & How It's Used
Heart Rate
Real-time heart rate readings are accessed from the Apple Watch optical sensor via HealthKit during active workout sessions. Heart rate data is displayed on the watch and iPhone, relayed from watch to iPhone via WatchConnectivity (Apple's encrypted on-device channel), and broadcast locally over Bluetooth Low Energy to nearby connected fitness equipment. Heart rate data is not persisted by the app beyond the active session. It is optionally saved to Apple Health as part of workout data (user-controlled).
Resting Heart Rate
Your resting heart rate is read from Apple Health to calculate personalised heart rate zones using the Karvonen formula. If unavailable, a default of 72 BPM is used. This value is read on-demand and not stored separately by the app.
Date of Birth
Your date of birth is read from Apple Health to estimate maximum heart rate (220 − age) for zone calculation. If unavailable, you can enter it manually. This value is read on-demand and not stored separately by the app.
Workout Sessions
Workout session data (duration, heart rate samples, energy expended, workout type) is optionally saved to Apple Health at the end of each session. This is enabled by default and can be turned off in Settings. Workout data is stored in Apple Health (managed by iOS) and is not stored elsewhere by the app.
Data Transmission
All data transmission is local and on-device:
- Apple Watch → iPhone: Heart rate and energy data transmitted via WatchConnectivity, encrypted by iOS.
- iPhone → Fitness Equipment: Heart rate broadcast over Bluetooth Low Energy as a standard Heart Rate Service. BLE is a local, short-range wireless protocol (~10 metres). Data is only accessible to physically nearby paired devices.
- iPhone → Apple Health: Workout data optionally saved to Apple Health (user-controlled).
No data is transmitted to any remote server, cloud service, or third party at any point.
Bluetooth
The app uses the iPhone's Bluetooth to advertise a standard BLE Heart Rate Service (UUID 0x180D). BLE is a local-only, short-range protocol. Up to 3 external devices can connect simultaneously. The app uses background mode to continue broadcasting when the iPhone is locked. The BLE device name defaults to "Pulse Link" and is user-configurable in Settings.
Children's Privacy
The app does not knowingly collect data from children under 13. The app has no accounts, no analytics, and processes all data on-device.
Data Retention
The app does not maintain its own data store. Heart rate data exists only in memory during an active session. Workout data is optionally written to Apple Health, where it is managed by iOS's data retention policies and your controls.
Changes to This Policy
We may update this privacy policy from time to time. Changes will be posted on this page with an updated effective date. We encourage you to review this page periodically.
Contact
For privacy-related questions, contact us at pulse-link@humblemars.com.