Focus / Concentration: 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
Focus here is an experimental index. It does not measure attention, and a camera on your fingertip cannot know what you are thinking about. It averages two other indices in the tool, Energy and inverse Stress, so it is highest when your heart rate is moderate (at or below about 75 bpm) and your beat-to-beat rhythm is steady.
How this tool calculates it
Focus = 0.5 × Energy + 0.5 × (100 − Stress), limited to 0–100%. Energy = 90 − 1.5 × (heart rate above 75 bpm) − 80 × CSI; Stress = 130 × CSI, where CSI is the standard deviation of your RR intervals divided by their mean. 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
Moderate pulse and even beat intervals during the reading. This can go along with calm, steady work, but a relaxed person reading nothing at all will score the same.
Lower
A faster pulse, a more irregular rhythm, or a noisy signal from finger movement.
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. Heart signals change with concentration in lab studies, but not in a way that lets a short camera reading tell you how focused you are.
What actually helps
One task at a time
Set a clear goal for the next 25–50 minutes and remove obvious distractions.
Calm body first
Slow breathing for a few minutes before demanding work can lower arousal if you feel wired.
Rest
Sleep, hydration and regular breaks do more for concentration than any single number.
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
Focus rises when your pulse is moderate and your rhythm is steady. It is a hint about your body, not a reading of your mind.
Ready to measure?
The ONDA app works with your iPhone camera, Apple Watch and Apple Health.