Biomarkers · Autonomic
Heart Rate Variability (SDNN)
Higher values go with lower risk of death. No risk curve catalogued yet.
Published risk of death1.51×lowest quartile vs third quartile of SDNN (pulse rate variability, 5-min) (95% CI 1.15–1.98) · Japanese community residents aged 30-79 recruited 2009-2018, followed to end of 2022
What else moves this marker
They describe those study groups, not an individual, and an association is not a cause.
Diseases and conditions
| What | Effect on the marker | Comparison · population | Source |
|---|---|---|---|
| ↓ Anxiety disorders · patients with anxiety disorders vs healthy controls, resting state | SMD -0.3897 | anxiety disorder patients vs healthy controls · 4897 patients with anxiety disorders and 5559 controls (99 studies) | meta analysis · PMID 35340102 |
| ↓ Dementia and neurocognitive disorders · patients with dementia vs healthy controls, resting recordings | SMD -0.3059 | dementia patients vs healthy controls · Patients with dementia or mild cognitive impairment and healthy controls (24 studies) | meta analysis · PMID 33287558 |
| ↓ Dementia with Lewy bodies · patients with dementia with Lewy bodies vs healthy controls | SMD -1.4154 | dementia with Lewy bodies vs healthy controls · Patients with dementia with Lewy bodies and healthy controls (subgroup of 24-study meta-analysis) | meta analysis · PMID 33287558 |
Day-to-day noise on a wearable
How much a single day's nightly rmssd from a consumer wearable moves around a person's own level, from months of free-living data in open datasets (proxy: RMSSD is a different HRV index from SDNN). ICC is the share of variation that is between people: near 1, one day tells people apart; near 0, it is mostly noise. The smallest detectable change (95%) is the change a single day, or a 7-day mean, must exceed before it is more than noise. Days to average assumes days are independent; for resting heart rate they are not, so the true number is larger.
| Dataset | People · person-days | Within-person SD | ICC: one day · 7-day mean | Detectable change: one day · 7-day mean | Days to average |
|---|---|---|---|---|---|
| LifeSnaps | 39 · 2,424 | 10.60 ms | 0.75 · 0.95 | 29.39 · 11.11 | 35 for 5.00 ms |