Relaxation / Calmness: An Experimental Index
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 is
Relaxation here is an experimental index that goes up when your beat-to-beat rhythm looks steady and your Energy index is high (which in this tool mostly means your heart rate is not above about 75 bpm). It is not a measure of how calm you feel, and it is not a validated relaxation score.
How this tool calculates it
Relaxation = 60 × (1 − min(1, 1.5 × CSI)) + 0.2 × Energy, limited to 0–100%. CSI is the standard deviation of your RR intervals divided by their mean. Note that breathing rate is not part of this formula, even though slow breathing often does help you relax. 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
Higher
Your RR intervals varied little relative to their average, and your pulse was moderate. Sitting still with a clean signal pushes it up.
Lower
The rhythm looked more irregular (higher CSI) or your pulse was faster. Finger movement also adds irregularity and lowers the score.
Important limits
This is an experimental heuristic built from a few camera-derived inputs. It is not a validated physiological measure, it is not emotion detection, and it is not a medical test. Treat it as a rough hint about the direction your signal is moving, not as a verdict about how you feel. One quirk: in real physiology, a relaxed body often shows more beat-to-beat variation linked to breathing, while this index rewards less variation. That is one more reason to treat it as a rough hint only.
What actually helps
Slow breathing
Breathing slowly, around 5.5–6 breaths per minute (individually about 4.5–7) with a relaxed longer exhale, is a well-studied way to calm the body for most people.
Posture and stillness
Sit comfortably, drop your shoulders and rest your hand so the finger stays on the lens without pressing hard.
A few quiet minutes
Heart rate usually settles over several minutes of rest, not seconds.
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
Relaxation here mostly reflects a moderate pulse and a steady-looking rhythm. How you feel matters more than the number.
Ready to measure?
The ONDA app works with your iPhone camera, Apple Watch and Apple Health.