Scientific five-minute HRV calculator
Calculate and interpret five-minute HRV against scientific reference data.
Connect a Polar H10 for a guided supine recording, or upload an existing HRV report and enter values manually. 5HRV calculates RMSSD, SDNN, pNN50, LF, HF and LF/HF directly in your browser and interprets them against age- and sex-specific reference data.
30.40 ms
RMSSD
47.63 ms
SDNN
3.28
LF/HF
Time domain: SDNN 47.63 ms, RMSSD 30.40 ms; frequency domain: HF 125.95 ms², LF 400 ms², LF/HF 3.28. The recording shows preserved overall variability, preserved parasympathetic activity and a central autonomic pattern.
HRV reports provide numbers. Interpretation requires context.
Exported HRV reports often contain RMSSD, SDNN, pNN50, HF and LF without a coherent interpretation. Values depend on age, sex, recording duration, rhythm, breathing and artefact handling. 5HRV applies a defined framework to turn those measurements into a structured scientific report.
What 5HRV does
Measures
Guides a standardized supine Polar H10 recording and calculates the principal five-minute HRV parameters directly from RR intervals.
Interprets
Places RMSSD and SDNN within age- and sex-specific reference distributions from the DanFunD population study.
Summarizes
Produces a concise scientific summary and structured report that can be copied or printed.
How it works
Measure or enter
Connect a Polar H10 for a guided supine measurement, or upload an existing report and enter previously calculated values.
Calculate
5HRV calculates RMSSD, SDNN, pNN50, LF, HF and LF/HF directly in your browser from the received RR intervals or entered values.
Interpret
Review recording quality, age- and sex-specific reference placement and the structured scientific analysis.
You can also upload an existing HRV report or enter previously calculated values manually.
30.40
RMSSD
ms
47.63
SDNN
ms
3.3
pNN50
%
126
HF
ms²
400
LF
ms²
3.28
LF/HF
Time domain: SDNN 47.63 ms, RMSSD 30.40 ms, pNN50 3.3%; frequency domain: HF 125.95 ms², LF 400 ms², LF/HF 3.28. The recording shows preserved overall variability, preserved parasympathetic activity and a central autonomic pattern.
A result designed to be read, copied and printed as a scientific report.
Every interpretation includes an Autonomic Pattern Score, individual metric placement with percentile categories, and a scientific analysis paragraph—all derived from the same underlying framework.
Built on established HRV methodology
5HRV combines international HRV measurement standards with age- and sex-stratified short-term reference data from the DanFunD population study. The framework distinguishes robust time-domain measures—RMSSD as the principal short-term vagal-related measure, SDNN as total five-minute variability—from more method-sensitive spectral parameters (HF and LF). LF/HF is a calculated descriptive ratio, not a direct measurement of autonomic balance. Standardized recording conditions are essential for reproducible interpretation.
Professional applications
Autonomic assessment
Non-invasive characterization of autonomic function from a standardized recording.
Orthostatic and post-acute infection research
Standardized HRV measurement in POTS, ME/CFS and Long COVID research protocols.
Longitudinal monitoring
Repeatable short-term recordings to track changes over time under consistent conditions.
Interventional and observational studies
Reproducible autonomic outcome measurement suitable for interventional and cohort studies.
Designed for practical use
All calculations run in the browser and no data is transmitted to a server. Entered values are retained only temporarily in the current browser tab so the result page can be displayed, and no personal identifiers are required. Results can be copied or printed directly from the report page.