Your heart,
in 30 seconds.

Cuore uses photoplethysmography (PPG), the same sensing technique used in dedicated fitness trackers and pulse oximeters. Under normal conditions — still finger, adequate contact with the lens — measurements are clinically comparable to dedicated pulse sensors. Results may vary with motion, poor circulation, or cold fingers. Cuore is not a medical device.

Cuore requires iOS 17.0 or later and a rear camera with a flash. It works on all iPhones that support iOS 17 — iPhone XS and newer. It is optimised for iPhone and is not available on iPad.

Heart Rate Variability (HRV) measures the variation in time between consecutive heartbeats. A higher RMSSD — what Cuore reports — generally indicates a well-functioning autonomic nervous system and better ability to adapt to stress. Athletes and health researchers use HRV to track recovery and overtraining. It drops when you're stressed, sleep-deprived, or unwell, often before you consciously notice.

No. All measurements are stored locally on your iPhone using SwiftData. Cuore has no backend server, no analytics SDKs, and no cloud sync. Your health data never leaves your device unless you explicitly share it via Apple Health.

The stress classification is derived from your HRV (RMSSD) reading and calibrated against published population reference ranges. Lower HRV correlates with higher sympathetic nervous system activity — what we experience as stress. The result is shown as a descriptive label (Very Relaxed → Very Stressed) alongside a numeric score.

Yes. Cuore Pro is a standard App Store subscription managed entirely by Apple. You can cancel at any time through the Settings app or your Apple ID subscription page. Access continues until the end of the current billing period.