Highlights from our new study for the special issue on “Wearables and the ANS” in Autonomic Neuroscience (full text below).

Aim 1: Test the validity of the Polar H10 vs ECG for HRV and standard cardiac autonomic reflex tests using a time-efficient protocol (see Pic 3).

Aim 2: Determine the extent to which supine RMSSD captures variability in other cardiovagal markers (deep breathing test, orthostatic reflex test, standing RMSSD).

Findings:

Relative agreement was near-perfect across all metrics, with negligible bias, narrow 95% limits of agreement, and MAPE consistently <1%.

Supine HRV explained between none and half of the variance in markers of cardiovagal function from separate assessments.

We explain why supine HRV is limited as a standalone index with examples (see Pic 4).

Instead of conventional supine HRV, which provides 1 assessment in ~10 min (5 min stabilization, 5 min recording), consider this shorter (8 min) protocol that includes 4 distinct assessments for a more comprehensive evaluation.

For remote monitoring, chest-strap ECG assessment should be prioritized over optical wearable sensors such as wristbands and smartwatches, which remain susceptible to substantial error in HRV estimation.

The H10’s ease of use, low cost, and lack of disposable electrodes make it well-suited for remote monitoring and field-based testing, while its high measurement accuracy supports its use in laboratory or clinical settings when traditional ECG is impractical or unavailable.