Summary
| Direction in PACVS | ↓ Reduced — lower than in the comparison group |
|---|---|
| Category | Functional |
| Also described as | Autonomic function |
| Compared against | HC (healthy controls) |
| Associated symptoms | Dysautonomia, POTS |
| Test type | Clinical or physiological test |
| Source | Mundorf et al. 2024 — doi:10.3390/vaccines12070790 |
| Condition atlas | PACVS Biomarker Atlas |
Other conditions where Heart rate variability (HRV) is reported
- Heart rate variability (HRV) in Gulf War Illness — ↓ reduced vs HGV
- Heart rate variability (PTLDS) in Lyme Disease — ↓ reduced vs HC
- Heart rate variability (RMSSD) in ME/CFS — ↓ reduced vs HC
- Heart rate variability (SDNN) in ME/CFS — ↓ reduced vs HC
See the cross-condition hub: Heart rate variability (HRV) across conditions.
Trials, interventions and tests
In clinical-trial registrations this marker maps to the outcome term Autonomic Function (13 registered trials use a matching outcome measure).
Clinical trials using Heart rate variability (HRV) as an outcome
- NCT07317401: Investigating the Effects of Intermittent Hypoxia-Hyperoxia Treatment (IHHT) in People With Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) to Improve Fatigue, Pain, and Quality of Life by Targeting Mitochondrial Dysfunction and Autonomic Nervous System Impairment (Not Yet Recruiting)
Outcome measure: Objective autonomic, neurophysiological, and functional performance measures - NCT05697640: Study to Investigate Improvement in Physical Function in SF-36 With Vericiguat Compared With Placebo in Participants With Post-COVID-19 Syndrome (Active Not Recruiting)
Outcome measure: Improvement in symptoms of autonomic dysfunction as measured by the Composite Autonomic Symptom Score (COMPASS-31) - NCT05710770: Immunoadsorption in Patients With Chronic Fatigue Syndrome Including Patients With Post-COVID-19 CFS (Completed)
Outcome measure: Improvement in symptoms of autonomic dysfunction as measured by the Composite Autonomic Symptom Score (COMPASS-31) - NCT07190105: Vagal Approaches on Long COVID-19 (Completed)
Outcome measure: Body Perception Questionnaire (BPQ) - NCT07110714: Effects of Kneipp Hydrotherapy in Post-COVID-19 Patients (Recruiting)
Outcome measure: Autonomic function (heart rate variability by photoplethysmography) - NCT06968104: Vagus Nerve Stimulation to the Ear to Improve Symptoms in Post-COVID-19 and ME/CFS (Active Not Recruiting)
Outcome measure: Autonomic Function - NCT05630040: VNS for Long-COVID-19 (Completed)
Outcome measure: Composite Dysautonomia Symptom Score (COMPASS 31) - NCT05566379: Mindfulness in Post Acute Sequelae of SARS-CoV-2 Infection (PASC) Dysautonomia (Completed)
Outcome measure: Change from baseline in the composite autonomic symptom score COMPASS-31 for autonomic symptoms
5 more trials reference this marker.
Interventions studied alongside this marker
Hypothesis-generating links from trial outcome usage and literature co-occurrence. Not treatment recommendations.
- Vagus nerve stimulation — 2 trials, 6 PubMed co-citations
e.g. From Therapeutic Heterogeneity to Precision Neuromodulation: Non-Invasive Brain Stimulation for Chronic… - Acceptance and commitment therapy — 1 trial, 6 PubMed co-citations
e.g. User Experience and Clinical Utility of a Smartphone-Based Application for Hwa-Byung Treatment: a protocol… - Inspiratory muscle training — 1 trial, 6 PubMed co-citations
e.g. Competing Demands: Acute Effects of Inspiratory Load on Hemodynamics and Vastus Lateralis Deoxygenation… - Coenzyme Q10 — 1 trial, 6 PubMed co-citations
e.g. Royal Jelly Plus Coenzyme Q10 Supplementation Enhances High-Intensity Interval Exercise Performance via…
Commercial test availability
Heart Rate Variability — specialty laboratory test. Functional autonomic measure; ordered via autonomic/POTS workup, not a single standard lab code.
Links are for reference only; availability, specimen requirements and coverage vary by location.
Related Functional markers in PACVS
- Salivary nitric oxide ↓
- Orthostatic heart rate increment ↑
- 6-minute walk distance ↓
- Exertional SpO₂ nadir ↓
- Chester Step Test (VO₂ proxy) ↓
- PAC-19QoL score ↓
- Neurofilament light chain (NfL) ↑
Full list: PACVS Biomarker Atlas.
Frequently asked questions
Is Heart rate variability (HRV) high or low in PACVS?
Reduced. Studies summarised in the OSMF atlas report lower Heart rate variability (HRV) in PACVS than in healthy controls. Source: Mundorf et al. 2024.
What symptoms is Heart rate variability (HRV) associated with in PACVS?
The cited literature associates this marker with Dysautonomia, POTS. These are population-level associations and do not mean the marker causes the symptoms.
Which test measures Heart rate variability (HRV)?
It is measured as a clinical or physiological test. Commercial laboratories such as NASA Lean Test / clinical autonomic workup list an orderable assay.
Is one abnormal Heart rate variability (HRV) result diagnostic of PACVS?
No. No single biomarker is diagnostic of PACVS. Heart rate variability (HRV) findings come from group comparisons, overlap considerably between patients and controls, and vary with study design, timing and comparison group. A result should be interpreted by a clinician alongside symptoms, history and other tests.
Is Heart rate variability (HRV) specific to PACVS?
No. The same marker is also reported in Gulf War Illness, Lyme Disease, ME/CFS in this atlas, so it reflects shared biology (for example inflammation or vascular stress) rather than a condition-specific signature.
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Last reviewed: 2026-06-30 · Page generated from pacvs.json · Browse: PACVS atlas · Biomarker Index · All marker pages
Disclaimer: This page is an educational synthesis of published, peer-reviewed research and is not medical advice. Biomarker findings vary across studies with case definitions, comparison groups, timing and assay methods. Direction of change reflects the predominant finding in the cited source and does not establish a diagnostic threshold. Discuss any test result with a qualified clinician.