Coherence App

iPhone / Forme et santé

Coherence is a structured physiological evaluation app built around Heart Rate Variability (HRV) and guided breathing sessions.

It does not measure relaxation.
It evaluates autonomic behavior, cardiac coherence and recovery patterns through structured session analysis.

HOW SESSIONS WORK

Sessions are started from Apple Watch. Breathing is guided using haptic feedback and color cues:

• Haptic + blue = nasal inhalation
• No haptic + green = nasal exhalation

Inhalation timing is detected algorithmically in real time. The ITFD algorithm continuously evaluates HRV dynamics and determines the optimal breathing rate and inhalation–exhalation structure during the session.

Signal acquisition is performed through Apple Watch. When available, external chest straps such as Movesense or Polar H10 can be used to refine HRV signal quality and improve algorithmic precision.

If the HUM button is blinking before starting, the ITFD algorithm has detected that adding humming during exhalation is recommended.

Humming is performed as Single-Breath Humming: a steady low sound during the entire exhale, producing stable nasal vibration. This vibratory nasal exhalation is associated with nitric oxide (NO) release. For more detailed information, see the corresponding sections in the Features area of our site.

To avoid consciously forced diaphragmatic breathing, the app proposes a light index–thumb opposition as a sensorimotor anchor. This subtle gesture supports postural stability and reduces accessory respiratory engagement without deliberate control. For more detailed information, see the corresponding sections in the Features area of our site.

MEASUREMENT AND INTERPRETATION

Each session generates an ITFD score derived from HRV behavior across repeated sessions. The model integrates SDNN and RMSSD dynamics to provide structured physiological interpretation.

The main card displays, by default, the latest recorded session. If a specific day is selected in the calendar, the card reflects the results of that selected session instead.

The dynamic background and main card interface include real-time graphical responses to physiological data during the session. Visual intensity and motion adapt continuously to coherence and stress dynamics, functioning as structured biofeedback rather than decorative animation.

The main card includes:

• A 7-day mini-chart showing daily minimum and maximum ITFD values
• Directional change compared to the previous session
• An interpretive phrase integrating structural analysis and circadian context
• A selectable calendar
• A 30-day trend summarizing overall progression

The interpretive phrase reflects the session within the system’s daily pattern, not only an isolated change.

In addition to the main interpretation, each session includes detailed charts displaying stress, coherence, and heart rate (HR) data. These charts provide structured visual feedback and allow observation of session dynamics both in real time and retrospectively.

STRUCTURE

The app is ideally designed for one session in the morning and one in the evening to evaluate daily autonomic patterning. Early sessions progressively stabilize as more data is recorded.

Coherence does not provide generic stress scores, motivational framing, or lifestyle coaching.

It is designed for users interested in structured HRV interpretation, cardiac coherence analysis, and measurable autonomic dynamics.