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Mind, Body,& the Mechanisms of Relief

Experimental methods + reporting · August 2026

Testing a multimodal measurement workflow

An improvised six-stage session combining phenomenological interviews, a laboratory recorder, and a mobile wearable.

Abstract

One adult participant · descriptive pilot · no efficacy inference

An improvised session combined two interviews, two state-shifting interventions, a BIOPAC MP36, and an Astroskin wearable. The first aim was to capture, align, analyze, and report the sequence as one reproducible record. The second was to evaluate the mobile system beside the laboratory acquisition.

Heart-rate trajectories and matched-beat variability agreed closely. Both systems showed slow breathing during music. Later respiration diverged because the waveforms contained slow cycles and faster substructure. Finger and forehead PPG amplitude also differed, showing why sensor location matters. The outcome is a working acquisition and analysis pipeline, a clear account of its limits, and a more specific repeat protocol.

Experimental sequence

The full experimental sequence

The first interview occurred before physiological recording. The MP36 and wearable then ran continuously through two resting periods, music, a second interview, and the final intervention.

Swipe to follow the full sequence →

Immediately before 00:0000:0007:2413:2113:5019:1125:21
30:37
Instruction · 29 sec
MP36 physiologyContinuous from 00:00Wearable physiologyContinuous from 00:00Interview activePre-sessionPost-music
The pre-recording interview appears at a fixed width because its exact duration is unavailable. From 00:00 onward, widths follow recorded duration. The labelled 29-second instruction interval falls outside the quiet Baseline 2 analysis.

Instrumentation

Laboratory and wearable measurement systems

Shared channels allow direct comparison. Different sensor locations and the wearable’s additional context channels show what each system contributes.

Laboratory system

BIOPAC MP36 · 500 Hz

ECG · finger PPG · respiratory belt

High-resolution waveforms, direct event capture, and full access to the recorded channels.

Mobile wearable

Astroskin · Hexoskin platform

Three-lead ECG · forehead PPG · thoracic and abdominal respiration

Continuous mobile sensing plus motion, position, temperature, oxygen saturation, and signal-quality channels.

Raw signal

ECG

Both systems captured comparable cardiac peaks and beat timing.

Raw signal

Respiration

The belts agreed during slow breathing and diverged when waveform structure became more complex.

Raw signal

PPG

Finger and forehead pulse amplitude differed, showing why sensor location must remain explicit.

Results

Cross-device comparison

Section values are whole-phase medians or matched-beat summaries. Each breathing-rate value is calculated from individual breath periods and retains decimal precision.

Heart rate

r = 0.997

0.21 BPM median absolute difference across 28 one-minute windows

RMSSD

≤ 0.4 ms

section differences after matching beats detected in both raw ECG recordings

Respiration

r = 0.452

0.25 cycles/min median absolute difference overall, with a large final-phase disagreement

ECG-to-PPG timing

r = 0.589

moderate trajectory agreement across non-equivalent finger and forehead pulse landmarks

Heart rate

BPM
Baseline 182.1 / 81.7
Music82.0 / 82.2
Baseline 286.6 / 86.7
Interview85.8 / 86.2
Altered78.6 / 78.5
MP36Wearable

RMSSD

ms · matched beats
Baseline 150.7 / 50.6
Music36.2 / 36.4
Baseline 233.1 / 33.0
Interview39.4 / 39.8
Altered47.0 / 47.1
MP36Wearable

Breath-period rate

cycles/min
Baseline 16.47 / 5.34
Music4.88 / 4.75
Baseline 25.05 / 5.09
Interview5.04 / 5.01
Altered8.34 / 5.59
MP36Wearable

PPG pulse amplitude

index · first baseline = 100
Baseline 1100 / 100
Music104 / 102
Baseline 271 / 103
Interview77 / 103
Altered86 / 102
MP36Wearable

Time course

Physiology across the full session

Aligned 60-second summaries show when the two systems followed the same trajectory and when sensor location or signal structure produced different estimates.

Swipe to inspect the full time course →

Physiology across the recorded sessionFive aligned time-series panels compare the MP36 laboratory recorder and Astroskin wearable during Baseline 1, music, Baseline 2, the interview, and the final intervention.B1MusicB2InterviewFinalHeart rateBPM7488102MP36, 0.5 min: 82Astroskin, 0.5 min: 82MP36, 1.5 min: 83Astroskin, 1.5 min: 83MP36, 2.5 min: 79Astroskin, 2.5 min: 79MP36, 3.5 min: 86Astroskin, 3.5 min: 85MP36, 4.5 min: 80Astroskin, 4.5 min: 79MP36, 5.5 min: 79Astroskin, 5.5 min: 79MP36, 6.5 min: 82Astroskin, 6.5 min: 82MP36, 7.9 min: 79Astroskin, 7.9 min: 79MP36, 8.9 min: 79Astroskin, 8.9 min: 79MP36, 9.9 min: 85Astroskin, 9.9 min: 85MP36, 10.9 min: 78Astroskin, 10.9 min: 78MP36, 11.9 min: 84Astroskin, 11.9 min: 84MP36, 14.3 min: 89Astroskin, 14.3 min: 89MP36, 15.3 min: 86Astroskin, 15.3 min: 86MP36, 16.3 min: 89Astroskin, 16.3 min: 89MP36, 17.3 min: 82Astroskin, 17.3 min: 82MP36, 18.3 min: 83Astroskin, 18.3 min: 83MP36, 19.7 min: 100Astroskin, 19.7 min: 100MP36, 20.7 min: 86Astroskin, 20.7 min: 86MP36, 21.7 min: 83Astroskin, 21.7 min: 83MP36, 22.7 min: 85Astroskin, 22.7 min: 86MP36, 23.7 min: 79Astroskin, 23.7 min: 79MP36, 24.7 min: 84Astroskin, 24.7 min: 84MP36, 25.9 min: 79Astroskin, 25.9 min: 80MP36, 26.9 min: 78Astroskin, 26.9 min: 78MP36, 27.9 min: 79Astroskin, 27.9 min: 79MP36, 28.9 min: 75Astroskin, 28.9 min: 76MP36, 29.9 min: 79Astroskin, 29.9 min: 79Matched-beat RMSSDms204570MP36, 0.5 min: 48Astroskin, 0.5 min: 48MP36, 1.5 min: 45Astroskin, 1.5 min: 44MP36, 2.5 min: 65Astroskin, 2.5 min: 66MP36, 3.5 min: 40Astroskin, 3.5 min: 40MP36, 4.5 min: 56Astroskin, 4.5 min: 55MP36, 5.5 min: 51Astroskin, 5.5 min: 51MP36, 6.5 min: 51Astroskin, 6.5 min: 51MP36, 7.9 min: 36Astroskin, 7.9 min: 37MP36, 8.9 min: 32Astroskin, 8.9 min: 32MP36, 9.9 min: 44Astroskin, 9.9 min: 44MP36, 10.9 min: 34Astroskin, 10.9 min: 34MP36, 11.9 min: 27Astroskin, 11.9 min: 27MP36, 14.3 min: 40Astroskin, 14.3 min: 40MP36, 15.3 min: 32Astroskin, 15.3 min: 33MP36, 16.3 min: 38Astroskin, 16.3 min: 39MP36, 17.3 min: 27Astroskin, 17.3 min: 26MP36, 18.3 min: 31Astroskin, 18.3 min: 31MP36, 19.7 min: 25Astroskin, 19.7 min: 26MP36, 20.7 min: 45Astroskin, 20.7 min: 46MP36, 21.7 min: 42Astroskin, 21.7 min: 42MP36, 22.7 min: 40Astroskin, 22.7 min: 40MP36, 23.7 min: 41Astroskin, 23.7 min: 41MP36, 24.7 min: 40Astroskin, 24.7 min: 40MP36, 25.9 min: 47Astroskin, 25.9 min: 47MP36, 26.9 min: 49Astroskin, 26.9 min: 49MP36, 27.9 min: 44Astroskin, 27.9 min: 44MP36, 28.9 min: 42Astroskin, 28.9 min: 41MP36, 29.9 min: 54Astroskin, 29.9 min: 54Breath-period ratecycles/min3711MP36, 0.5 min: 7Astroskin, 0.5 min: 5MP36, 1.5 min: 7Astroskin, 1.5 min: 6MP36, 2.5 min: 6Astroskin, 2.5 min: 4MP36, 3.5 min: 6Astroskin, 3.5 min: 5MP36, 4.5 min: 4Astroskin, 4.5 min: 6MP36, 5.5 min: 7Astroskin, 5.5 min: 6MP36, 6.5 min: 7Astroskin, 6.5 min: 6MP36, 7.9 min: 4Astroskin, 7.9 min: 4MP36, 8.9 min: 5Astroskin, 8.9 min: 5MP36, 9.9 min: 4Astroskin, 9.9 min: 4MP36, 10.9 min: 5Astroskin, 10.9 min: 5MP36, 11.9 min: 5Astroskin, 11.9 min: 5MP36, 14.3 min: 6Astroskin, 14.3 min: 6MP36, 15.3 min: 6Astroskin, 15.3 min: 6MP36, 16.3 min: 5Astroskin, 16.3 min: 5MP36, 17.3 min: 5Astroskin, 17.3 min: 5MP36, 18.3 min: 4Astroskin, 18.3 min: 4MP36, 19.7 min: 6Astroskin, 19.7 min: 5MP36, 20.7 min: 5Astroskin, 20.7 min: 5MP36, 21.7 min: 5Astroskin, 21.7 min: 5MP36, 22.7 min: 5Astroskin, 22.7 min: 5MP36, 23.7 min: 6Astroskin, 23.7 min: 6MP36, 24.7 min: 4Astroskin, 24.7 min: 4MP36, 25.9 min: 9Astroskin, 25.9 min: 5MP36, 26.9 min: 8Astroskin, 26.9 min: 7MP36, 27.9 min: 8Astroskin, 27.9 min: 5MP36, 28.9 min: 8Astroskin, 28.9 min: 6MP36, 29.9 min: 9Astroskin, 29.9 min: 6PPG pulse amplitudewithin-site index60103145MP36, 0.5 min: 140Astroskin, 0.5 min: 100MP36, 1.5 min: 115Astroskin, 1.5 min: 99MP36, 2.5 min: 88Astroskin, 2.5 min: 99MP36, 3.5 min: 90Astroskin, 3.5 min: 99MP36, 4.5 min: 97Astroskin, 4.5 min: 100MP36, 5.5 min: 104Astroskin, 5.5 min: 101MP36, 6.5 min: 92Astroskin, 6.5 min: 102MP36, 7.9 min: 85Astroskin, 7.9 min: 102MP36, 8.9 min: 99Astroskin, 8.9 min: 102MP36, 9.9 min: 116Astroskin, 9.9 min: 102MP36, 10.9 min: 120Astroskin, 10.9 min: 102MP36, 11.9 min: 112Astroskin, 11.9 min: 103MP36, 14.3 min: 71Astroskin, 14.3 min: 104MP36, 15.3 min: 71Astroskin, 15.3 min: 104MP36, 16.3 min: 65Astroskin, 16.3 min: 103MP36, 17.3 min: 75Astroskin, 17.3 min: 103MP36, 18.3 min: 71Astroskin, 18.3 min: 103MP36, 19.7 min: 75Astroskin, 19.7 min: 102MP36, 20.7 min: 86Astroskin, 20.7 min: 103MP36, 21.7 min: 78Astroskin, 21.7 min: 103MP36, 22.7 min: 76Astroskin, 22.7 min: 103MP36, 23.7 min: 76Astroskin, 23.7 min: 103MP36, 24.7 min: 72Astroskin, 24.7 min: 103MP36, 25.9 min: 74Astroskin, 25.9 min: 103MP36, 26.9 min: 77Astroskin, 26.9 min: 101MP36, 27.9 min: 85Astroskin, 27.9 min: 102MP36, 28.9 min: 97Astroskin, 28.9 min: 101MP36, 29.9 min: 96Astroskin, 29.9 min: 101ECG → PPG timingchange from B1, ms-25-3+20MP36, 0.5 min: -2Astroskin, 0.5 min: +15MP36, 1.5 min: +2Astroskin, 1.5 min: +3MP36, 2.5 min: +2Astroskin, 2.5 min: +1MP36, 3.5 min: 0Astroskin, 3.5 min: -10MP36, 4.5 min: 0Astroskin, 4.5 min: -13MP36, 5.5 min: +2Astroskin, 5.5 min: -2MP36, 6.5 min: 0Astroskin, 6.5 min: +1MP36, 7.9 min: -4Astroskin, 7.9 min: -2MP36, 8.9 min: +1Astroskin, 8.9 min: -4MP36, 9.9 min: -4Astroskin, 9.9 min: -7MP36, 10.9 min: 0Astroskin, 10.9 min: -1MP36, 11.9 min: -4Astroskin, 11.9 min: +1MP36, 14.3 min: -16Astroskin, 14.3 min: -10MP36, 15.3 min: -14Astroskin, 15.3 min: -10MP36, 16.3 min: -12Astroskin, 16.3 min: -10MP36, 17.3 min: -2Astroskin, 17.3 min: -3MP36, 18.3 min: -9Astroskin, 18.3 min: 0MP36, 19.7 min: -16Astroskin, 19.7 min: -23MP36, 20.7 min: -18Astroskin, 20.7 min: -17MP36, 21.7 min: -16Astroskin, 21.7 min: -8MP36, 22.7 min: -12Astroskin, 22.7 min: -10MP36, 23.7 min: -8Astroskin, 23.7 min: -4MP36, 24.7 min: -8Astroskin, 24.7 min: -4MP36, 25.9 min: -8Astroskin, 25.9 min: -3MP36, 26.9 min: -4Astroskin, 26.9 min: -5MP36, 27.9 min: +1Astroskin, 27.9 min: -6MP36, 28.9 min: +2Astroskin, 28.9 min: -2MP36, 29.9 min: -2Astroskin, 29.9 min: -4051015202530minutes from physiology recording startMP36 laboratoryAstroskin wearable
Whole-session time course. Points summarize non-overlapping 60-second windows. Lines stop at phase boundaries. PPG amplitude is indexed within each sensor site; ECG-to-PPG timing is shown as within-device change from Baseline 1. Only the trajectories are comparable across those two tracks.
Music · 07:24–13:21

Slow breathing was the clearest shared pattern.

Both systems measured about 4.8 cycles per minute across the phase. Heart rate remained close to Baseline 1, while matched-beat RMSSD was lower. Whole-phase PPG pulse amplitude stayed near Baseline 1 at both the finger and forehead.

Final intervention · 25:21–30:37

Cardiac measures converged while respiration separated.

Both ECGs showed a lower heart rate and higher RMSSD than Baseline 2. The MP36 belt weighted faster respiratory substructure than the wearable belts. Finger PPG amplitude rose from its Baseline 2 low while forehead PPG remained stable, which argues against reading either site as a direct measure of systemic blood flow.

Phenomenology

Participant-reported experience

The first interview characterized the participant before recording. The second took place after the music and quiet rest periods.

After music + quiet rest

The participant reported feeling calmer and more tired or sleepy, with time passing somewhat more slowly.

Possible chills were rated 3/10 and described as localized. The selected track produced little response for this participant. The interview describes a low-intensity experience marked mainly by relaxation.

Responses recorded twice
Connection to the wider world
6 / 10 → 6 / 10
Bodily awareness
7 / 10 → 7.5 / 10 · limited
Curiosity
unchanged
Sense of self-boundary
possibly more porous · qualitative

Several questions were missing or changed wording and response anchors. The results are therefore reported item by item, with no combined score.

Next iteration

Repeat-study requirements

The pipeline worked. The next protocol should make intervention effects, time effects, and measurement disagreements easier to separate.

  1. 01Mark every boundary

    Write synchronized events into physiology, stimulus, and audiovisual records.

  2. 02Repeat and counterbalance

    Vary the order of music, quiet rest, interview, control, and intervention periods across repeated sessions.

  3. 03Standardize the interviews

    Use the same questions and response anchors before and after each target phase, and preserve qualitative detail.

  4. 04Add independent references

    Use airflow or capnography for breath identity and an appropriate reference before interpreting vascular transit or blood pressure.

  5. 05Test stimulus relevance

    Compare standardized and participant-selected music and collect immediate event-button and chill reports.

Data and methods for Commons members

The authenticated project folder contains the unchanged acquisitions, portable signal tables, event and section files, versioned analysis packages, checksums, and frozen tool copies. Maintained code and reporting sources live in the Commons repository.

Open the member CommonsReturn to the Summit

Single-participant descriptive pilot with one fixed-order session. PPG pulse amplitude reports local pulsatile blood-volume change at the sensor site. ECG-to-PPG intervals include pre-ejection time; pulse-transit interpretation would require an independent reference. Analysis version 4 · 4 September 2026.