BIOLOGICAL
HRV drift compensation in long-form sessions
Sessions over 30 minutes show a 4-6% downward drift in HRV gain. Suspect carrier phase walk after thermal equilibration. Adding a 12-minute thermal pre-soak before the next cohort.
Context
Long-form coherence sessions are a core deliverable of the 432Hz cohort. Reproducible HRV gain over the full session window is the contract we make with clinical partners — any systematic drift erodes confidence in the protocol.
Method
- 01Cohort of N=18 subjects, 45-minute supine sessions, polar H10 chest strap sampled at 1kHz.
- 02Generator hardware was a single Mk II unit, ambient temperature logged at 30s intervals.
- 03HRV gain computed as RMSSD ratio between minute 5 baseline and a rolling 5-minute window.
Findings
- ▸Gain plateaus at minute 12, then drifts down 4-6% by minute 30.
- ▸Drift onset correlates (r=0.71) with a +3.2°C rise in chassis temperature.
- ▸Subjects report no perceptible change in session quality across the drift window.
Next steps
Add a 12-minute thermal pre-soak before the next cohort begins recording. If drift disappears, we'll fold the pre-soak into the published session protocol and revisit oscillator selection separately.