# Diel

> Diel is a personal stress and recovery index for iPhone and Apple Watch. It compares signals from Apple Health and everyday context with your own baseline, helping you understand your daily rhythm.

## Product

- App: Diel
- Platform: iOS and watchOS
- Core idea: a relative index, not an absolute measurement
- Inputs: heart and recovery signals, sleep, movement, daylight, respiratory rate, wrist temperature, mood, caffeine, alcohol, and optional cycle context
- Calibration: Diel learns a personal baseline over roughly 7–14 days
- Privacy: Health data is processed on the device and Diel does not write data back to Apple Health
- Medical disclaimer: Diel does not measure cortisol, diagnose conditions, or provide medical advice

## Pages

- [Home](https://diel.primary0.com/): What Diel does and how it works.
- [Support](https://diel.primary0.com/support): Help and contact information.
- [Privacy Policy](https://diel.primary0.com/privacy): How Diel handles health data and analytics.
- [Terms of Use](https://diel.primary0.com/terms): Terms for using Diel.

## Contact

- Support: use the support form at https://diel.primary0.com/support