Recovery Rate: How Fast Your Pulse Settles
Estimated from a single camera (PPG) reading — an educational estimate, not a medical measurement. State labels (Flow, Focus, Alarm…) are rough, experimental patterns, not emotion detection.
What this number shows
Recovery Rate in this tool is a within-window measure. It looks at the highest heart rate in the last 15 seconds and asks how far the most recent beat has come back from that peak toward the window average. It is not the same as the clinical "heart rate recovery" test, which measures how many beats per minute your pulse drops in the first minute after hard exercise.
How this tool calculates it
For each beat the tool converts the RR interval to beats per minute. If the peak is at least 2 bpm above the window average, Recovery = (peak − latest beat) ÷ (peak − average) × 100, limited to 0–100%. If there was no clear peak, the value is 0. The tool works on a rolling 15-second window of fingertip video (about 30 frames per second), finds each pulse peak, keeps only beat-to-beat (RR) intervals between 400 and 1,500 ms that are within 22% of the median, and smooths the displayed numbers so they change gradually.
How to read it
Near 100%
The latest beat is back at (or below) your average for the window, so any short spike has passed.
Around 50%
Your pulse is about halfway back from its recent peak.
Near 0%
Either your pulse is still at its peak, or there was no noticeable peak at all (a steady reading also shows 0). Check the other numbers to tell these apart.
Why it moves a lot
Heart rate naturally rises on each inhale and falls on each exhale, so the "peak" is often just the top of a breath cycle and the value can swing from beat to beat. A single false or missed beat from the camera can also create an artificial peak.
Recovery in the broader sense
Over hours and days, recovery is better judged by trends: morning resting heart rate, HRV measured the same way each day, sleep, and how you feel. After exercise, a faster drop in heart rate during the first minute is generally a sign of good fitness.
Important limits
This is a rough, experimental indicator of this browser tool, not a medical or training metric.
The ONDA app is a separate product: it focuses on pulse, breathing and, with an Apple Watch, coherence. It does not use the formulas on this page.
The ONDA Principle
High means your pulse is back near its average after a recent peak; 0% can also simply mean there was no peak.
Ready to measure?
The ONDA app works with your iPhone camera, Apple Watch and Apple Health.