Sleep Tracker - Cernidia

HRV Readiness & Recovery

Free

Make sense of your sleep, recovery and daily energy. Connect Apple Watch or WHOOP and find a useful next step for your day. Understand your signals. Shape your day around them. Cernidia helps you make sense of your sleep, recovery and daily energy, so everyday choices about rest, movement and focus have more context. See the bigger picture behind your numbers and notice patterns over time. No ads, subscriptions or in-app purchases. No Cernidia account needed. UNDERSTAND YOUR SIGNALS • Review your sleep and your next planned sleep window. • Follow your daily energy estimate and recovery in your personal context. • Explore breathing-rate trends, blood-oxygen readings and heart-rate zones when suitable data is available. • Add a quick check-in to record how you feel. CONNECT YOUR WEARABLES Use Apple Health with Apple Watch, or connect an existing WHOOP account. WHOOP Recovery, Sleep, Strain and Workouts are labelled separately. Connections are optional, and Cernidia remains usable without a wearable. PUT INSIGHTS INTO YOUR DAY Give tasks, routines and recovery time a place in your day. Optional calendar access helps your plans fit around real commitments. The Apple Watch companion shows your current and next activity, lets you record an energy check-in and adds heart-rate context to workouts you start. CHOOSE YOUR WAKE-UP WINDOW Smart Wake lets you choose a wake-up window and uses previously recorded sleep phases to estimate a wake time. Your latest wake time serves as a backup. Alarm or notification permissions are needed for alerts; Smart Wake does not detect your current sleep stage in real time. PRIVATE AND OPTIONAL Your health summaries, check-ins and plans stay on your devices. Cernidia has no app-data cloud sync, product analytics, advertising or cross-app tracking. The optional WHOOP connection uses an online authorization service. WHOOP health records are fetched directly to your iPhone and stored locally. WHAT TO EXPECT Personal comparisons need enough readable history. Missing data stays unknown. Features depend on your device, permissions and available records. Apple Watch and WHOOP devices are sold separately; WHOOP also requires its own membership. Cernidia supports general wellness and everyday decisions. It does not diagnose conditions or provide medical treatment recommendations.

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Updated sleep and recovery views, clearer optional health connections and refreshed App Store information. This version contains no product usage analytics.

Version 1.0.1

The developer, Sven Kraln, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Linked to You

    The following data may be collected and linked to your identity:

    • Location
    • Diagnostics
    • Other Data

Privacy practices may vary, for example, based on the features you use or your age. Learn More

Accessibility

The developer has not yet indicated which accessibility features this app supports. Learn More

Information

Seller
Sven Kraln
Size
24.7 MB
Category
Health & Fitness
Compatibility
Requires iOS 18.0 or later.
  • iPhone
    Requires iOS 18.0 or later.
  • Apple Watch
    Requires watchOS 10.0 or later.
Languages
English
Age Rating
9+
Copyright
© 2026 Sven Krain
  • Developer Website
  • Privacy Policy