Workout Lens

Privacy Policy

Effective date: 23 March 2026  ·  SYLERO B.V.

1. Introduction

This Privacy Policy describes how SYLERO B.V. ("SYLERO", "we", "us", or "our") handles information in connection with the Workout Lens iOS application ("the App").

The core principle of Workout Lens is simple: your health data never leaves your device unless you explicitly choose to export and share it yourself. We do not collect, store, or transmit your personal data to any server.

By using Workout Lens you acknowledge that you have read and understood this Privacy Policy.

2. Data Controller

The data controller responsible for the App is:

SYLERO B.V.
Chamber of Commerce (KVK): 69820309
VAT: NL858025607B01
The Hague, Netherlands
Email: hello@sylero.nl

For privacy-related inquiries you may also reach us at the same address with the subject line "Workout Lens — Privacy".

3. Data We Access

Workout Lens requests read access to your Apple Health (HealthKit) data solely to provide its core functionality: generating an export file of your workouts.

The App may read the following categories of HealthKit data, where available:

Workout metadata

  • Workout type (e.g. running, cycling, walking)
  • Start time, end time, and duration
  • Source application and source device

Health measurements per workout

  • Heart rate (time-series)
  • Cadence (steps per minute)
  • Running speed and pace
  • Distance
  • Active energy (kilocalories)
  • Elevation / altitude change (where available)

Workout structure

  • Lap and split events
  • GPS route points (latitude, longitude, altitude, timestamp)

Access is granted through the standard iOS HealthKit permission dialog. You may grant or revoke any of these permissions at any time via Settings → Privacy & Security → Health → Workout Lens on your iPhone.

The App does not access clinical health records, medical data, sleep data, nutrition data, or any other health categories beyond those listed above.

The App does not access your camera, microphone, contacts, photos library, location (outside of GPS data already recorded in HealthKit), or any other device data.

4. How We Process Data

All data processing takes place entirely on your device. The App reads HealthKit data, formats it into a structured CSV file, and presents that file to you for export. No data is transmitted to SYLERO's servers or to any third party at any point during this process.

The export file is created locally in your device's temporary storage and is handed to the iOS Share Sheet. What happens to the file after you share it — for example, if you send it to a cloud service or an AI application — is governed by the privacy policy of that destination service, not by this policy.

The App does not include any analytics SDKs, advertising SDKs, crash reporting SDKs, or any other third-party tracking libraries. No usage data, telemetry, or diagnostic information is collected.

Workout Lens is designed for users in the European Economic Area (EEA) and we comply with the General Data Protection Regulation (GDPR).

Because all data processing occurs locally on your device and no data is transmitted to us, SYLERO does not act as a data processor or controller of your HealthKit data in the traditional sense. However, to the extent that any processing of health data falls within the scope of the GDPR:

  • Legal basis (Art. 6(1)(b) GDPR): Processing is necessary to perform the service you requested — generating a workout export file.
  • Special category data (Art. 9(2)(a) GDPR): Health data is special category data. Your explicit consent is obtained through the iOS HealthKit permission dialog before any health data is accessed.

6. Data Sharing

SYLERO does not share, sell, rent, or otherwise disclose your health data to any third party. We receive no copies of your data.

The only "sharing" that occurs is when you use the iOS Share Sheet to export your file. This action is entirely under your control. The recipient of your export file (e.g., an AI application, a cloud storage service, an email recipient) is chosen solely by you.

7. Data Retention

SYLERO retains no health data. All data remains on your device at all times.

Export files generated by the App are temporary and are not stored by the App itself. If you save an export file to your device (e.g., via the Files app), it is stored under your control, subject to your device's own storage settings.

Deleting the App from your iPhone removes the App and its local storage. It does not affect the data in Apple Health, which is managed by iOS and Apple.

8. Security

Because no data is transmitted to any external server, the attack surface of Workout Lens is significantly reduced compared to cloud-based applications. Your health data is protected by the same iOS security mechanisms that protect all HealthKit data — including device encryption and the HealthKit access control layer.

We recommend keeping your iPhone's iOS version up to date to benefit from the latest Apple security updates.

9. Your Rights (GDPR)

As a data subject under the GDPR, you have the following rights. Given the local-only nature of this App, most of these rights can be exercised directly on your device:

Right of access (Art. 15)

All data the App accesses is visible within the App itself. You can view your workout data in the App at any time.

Right to rectification (Art. 16)

Workout Lens reads data from Apple Health. To correct health data, please do so in the Apple Health app on your iPhone.

Right to erasure (Art. 17)

You can revoke Workout Lens's access to your health data at any time via iPhone Settings. Deleting the App removes all local App data. Removing health records from Apple Health is done within the Apple Health app.

Right to restrict processing (Art. 18)

You can revoke HealthKit permissions at any time to stop the App from accessing your data, via Settings → Privacy & Security → Health → Workout Lens.

Right to data portability (Art. 20)

Workout Lens is itself a data portability tool — it exports your HealthKit data in machine-readable CSV format on demand.

Right to object (Art. 21)

You can object to processing at any time by revoking HealthKit permissions or deleting the App.

Right to lodge a complaint

If you believe your privacy rights have been infringed, you have the right to lodge a complaint with the Dutch supervisory authority:

Autoriteit Persoonsgegevens (AP)
Website: autoriteitpersoonsgegevens.nl

10. Children's Privacy

Workout Lens is not directed at children under the age of 13. We do not knowingly collect any personal information from children under 13. If you believe a child under 13 has used the App, please contact us at hello@sylero.nl so we can take appropriate action.

11. Changes to This Policy

We may update this Privacy Policy from time to time. When we do, we will revise the "Effective date" at the top of this page. For significant changes, we will also update the App's App Store description. We encourage you to review this policy periodically.

Continued use of Workout Lens after changes to this policy constitutes acceptance of the revised policy.

12. Contact

If you have any questions, concerns, or requests regarding this Privacy Policy or the handling of your data, please contact us:

SYLERO B.V.
Email: hello@sylero.nl
Subject: Workout Lens — Privacy
The Hague, Netherlands

We aim to respond to all privacy-related inquiries within 5 business days.