Health Data Agreement
Version 1.0 · Effective date: to be set on launch
Zensus is a health and nutrition tracking application. To provide its core service, Zensus must collect and process data that falls within the definition of special category data under Article 9 of the UK and EU General Data Protection Regulation. This agreement explains exactly what health data we collect, why, how it is protected, who else may access it, and your rights over it.
By tapping "I agree" during account setup, you give explicit consent under GDPR Article 9(2)(a) for Zensus to process your health data as described in this agreement, and you acknowledge that Zensus is a tracking tool and not a source of medical advice. This consent is separate from, and in addition to, your acceptance of our Terms of Service and Privacy Policy.
2. What Health Data We Collect
2.1 Dietary Data
Calorie intake; macronutrients (protein, carbohydrates, fats, broken down by source); micronutrients (all B vitamins, vitamin C, choline, vitamins A, D, E, K1, K2); minerals (potassium, magnesium, sodium, calcium, phosphorus, iron, zinc, iodine, selenium, copper, manganese); fatty acids; amino acids; dietary fibre; water intake; your daily nutrition targets; and a running daily aggregate of your intake across all food logs.
2.2 Body Measurements
Body weight and height; body circumferences (neck, chest, waist, hips, biceps, thighs, calves); strength benchmarks for key movement patterns; cardiovascular metrics (resting heart rate, VO2 max, ApoB). We maintain a historical record of all measurements so you can view trends over time.
2.3 Exercise Data
Resistance training (weight lifted, reps, estimated one-rep max, volume, RPE, distance, duration, notes) and endurance training (distance, speed, max heart rate, personal bests, intervals, incline, resistance level, RPE, notes).
2.4 Sleep Data
Sleep quality ratings you submit (a score from 1 to 10) against each date.
2.5 Profile and Demographic Data
Date of birth and gender (used to calculate age-appropriate nutrition targets and apply demographic presets), exercise frequency, and preferred unit system.
3. Why We Process This Data
The sole purpose of collecting this data is to provide the Zensus health and nutrition tracking service: displaying your daily intake and progress, calculating and updating your goals, tracking measurements and exercise capacity over time, displaying trends and progress charts, awarding achievements and leaderboard scores, and enabling Team comparisons.
We do not use your health data for advertising, profiling for third-party commercial purposes, or any purpose not listed above.
4. Legal Basis for Processing
We process your special category health data on the basis of your explicit consent under UK GDPR Article 9(2)(a) and EU GDPR Article 9(2)(a). You gave this consent by tapping "I agree" on this agreement during account setup. We record the date, time, language, and version of the agreement you consented to, along with a confirmation that you acknowledged the English version as legally binding (where applicable).
5. How We Protect Your Health Data
Encrypted at rest (application-level encryption in addition to database-level security): resting heart rate, VO2 max, and ApoB values; maximum heart rate during endurance exercise; all historical measurement values; personal notes attached to exercise logs.
Not separately encrypted at rest (protected by database-level security and access controls): food log nutrient values; body weight, height, and circumference measurements; exercise performance data; sleep ratings; date of birth and gender.
All data is transmitted over encrypted connections (TLS). Access to the database is restricted to authorised backend services and staff. Production health data is never used in development or testing environments.
6. Who Else Accesses Your Health Data
We share your health data with the following third-party processors only to the extent necessary to operate the service:
| Processor | Purpose | What they don't receive | Location |
|---|---|---|---|
| Sentry | Error monitoring — may receive request context (user ID, operation) if an error occurs | Actual health values | United States (SCCs apply) |
| PostHog | Product analytics — event type, premium status, country, platform | Health values | European Union |
| Supabase | Database hosting — infrastructure only | N/A — not used for any other purpose | United States |
| Fly.io | Application hosting — infrastructure only | N/A — not used for any other purpose | United States |
| Mailgun (Sinch) | Weekly nutrition report email — contains actual health data (top foods, macros, weekly averages); other account emails don't | — | United States (SCCs apply) |
| OneSignal | Push notifications — may reference measurement categories due, or points milestones | Actual health values (weight, calories, readings) | United States (SCCs apply) |
You can opt out of the weekly nutrition report and push notifications at any time via Profile → Notifications. Data processing agreements are in place with every processor listed above.
9. How Long We Keep Your Health Data
Your health data is stored for as long as your account is active — we do not apply a fixed retention period because the ongoing history of your measurements and food logs is the product. When you delete your account, all health data is permanently deleted within 30 days. Consent records (proof that you agreed to this document) are retained after account deletion as required by GDPR Article 7. See our Data Retention Policy for full detail across all data categories.
10. Your Rights
- Right of Access: request a copy of all health data via Profile → Privacy → Download My Data
- Right to Data Portability: the export is provided in structured JSON
- Right to Erasure: delete your account (30-day grace period) via Profile → Account → Delete Account
- Right to Withdraw Consent: because health data processing is fundamental to how Zensus works, withdrawal is only possible by deleting your account; this does not affect the lawfulness of processing before withdrawal
- Right to Rectification: correct inaccurate health data directly within the app
- Right to Lodge a Complaint: UK users — ICO (ico.org.uk); EU users — your local supervisory authority
11. Children and Young People
Zensus requires users to be at least 16 years old. We do not knowingly collect health data from anyone under 16 and will delete it promptly if we become aware of this.
Users aged 16–17 are permitted to use Zensus. In accordance with the UK Age Appropriate Design Code and EU GDPR Article 8, the following protections apply to all users, including those aged 16–17:
- No behavioural advertising or commercial profiling using health data
- Minimal data collection — only data necessary for the core tracking service
- No third-party data sharing beyond what is described in Section 6
- Full control over public leaderboard visibility at any time (see Section 7.1)
We do not currently apply an age-specific default to leaderboard visibility — the same default applies to all users regardless of age, and can be changed by any user at any time.
12. Changes to This Agreement
If we make material changes to the health data we collect or how we process it, we will present you with an updated version of this agreement and ask for your consent again before continuing to process your health data.
13. Contact
For our full privacy practices, see our Privacy Policy.