KnowYourPrime Evidence Registry · Finding KYP-ER-0014

Normal HRV Range by Age

Question assessedIs there a normal heart rate variability range, and does it change with age?

KnowYourPrime evidence ratingEstablishedStrong, consistent evidence supports the claim.

Yes, it falls with age. Resting HRV declines steadily from early adulthood in large reference studies and within the same people followed for 22 years, so a normal value has to be read against age, and reference ranges exist by sex and decade. The ranges are wide, and they come from ECG recordings, not from any wearable.

Finding KYP-ER-0014Version 1.0Reviewed October 24, 2026Rating rule 1.4CC BY 4.0

Why this is rated Established

Four anchor studies, including two built specifically to set reference values and one that measured the same people two decades apart, all find HRV decreasing with age. That consistent affirmation rates the claim Established.

Two studies add caveats rather than contradictions: HRV differs by ethnicity, with higher resting HRV in African Americans than European Americans in one meta-analysis, and an age difference seen during sleep was not found during a brief waking rest. A systematic review of normal values found variation between people so large that a single number is not meaningful.

How the rating rule reads this evidence

Anchor-grade evidence affirms the core relationship.
Multiple supporting studies are consistent with the core relationship.
Some evidence conflicts on secondary points that do not change the core direction.

Key results

From 24-hour Holter recordings in 695 healthy volunteers, reference values for SDNN, RMSSD, pNN50 and frequency measures were set for men and women in 10-year bands from 20 to 60, with 5th and 95th percentiles, and HRV measures decreased consistently with age. (Sammito et al., Heart Rhythm, 2018)
In 2,874 non-medicated healthy adults aged 35 to 74, almost all 5-minute resting HRV indices decreased with age in percentile curves by sex and decade. (Dantas et al., Psychophysiology, 2019)
In adults recorded in 1991 to 1993 and again in 2013 to 2014 (783 and 466 people), frequency-domain power, SDNN and nonlinear indices all fell significantly within the same people over 22 years. (Karhumaa et al., Autonomic Neuroscience, 2025)
A systematic review of 44 studies and 21,438 healthy adults found large methodological differences between studies and inter-individual variation reaching 260,000 percent for spectral measures. (Nunan et al., Pacing and Clinical Electrophysiology, 2011)

What this finding covers

Applies to: Resting HRV measured by ECG in healthy adults, by age and sex.

Does not cover: The specific HRV number any wearable reports, which uses its own method and timing and is not interchangeable with these reference values; HRV in people with heart disease or on medication.

Limitations

Reference values depend on the recording length and method, so a 5-minute value and a 24-hour value are not comparable.
Ranges are wide; a value outside them in one person is not by itself a finding.
Ethnicity and other factors shift values and are not reflected in most reference tables.

Evidence base

10 studies scored · 5 anchor · 2 conflicting · 3 supporting · Evidence last evaluated Oct 24, 2026

Anchor studies

The studies the rating rests on.

Changes and prognostic significance of autonomic cardiac regulation during ageing.Karhumaa et al., Autonomic Neuroscience, 2025. doi.org/10.1016/j.autneu.2025.103255
Reference values for short-term resting-state heart rate variability in healthy adults: Results from the Brazilian Longitudinal Study of Adult Health-ELSA-Brasil study.Dantas et al., Psychophysiology, 2019. doi.org/10.1111/psyp.13052
Reference values for time- and frequency-domain heart rate variability measures.Sammito et al., Heart Rhythm, 2018. doi.org/10.1016/j.hrthm.2016.02.006
A quantitative systematic review of normal values for short-term heart rate variability in healthy adults.Nunan et al., Pacing and Clinical Electrophysiology, 2011. doi.org/10.1111/j.1540-8159.2010.02841.x
Effect of age and sex on heart rate variability in healthy subjects.Zhang et al., Journal of Manipulative and Physiological Therapeutics, 2007. doi.org/10.1016/j.jmpt.2007.04.001

Conflicting studies

Studies whose findings run against the claim.

Age-related losses in cardiac autonomic activity during a daytime nap.Chen et al., Psychophysiology, 2022. doi.org/10.1111/psyp.13701
Ethnic differences in resting heart rate variability: a systematic review and meta-analysis.Hill et al., Psychosomatic Medicine, 2015. doi.org/10.1097/PSY.0000000000000133

Supporting studies

Studies consistent with the claim that do not carry the rating on their own.

Comprehensive linear and nonlinear heart rate variability normative data in children.Kakavand et al., Clinical Autonomic Research, 2025. doi.org/10.1007/s10286-024-01056-x
Heart rate variability: reference values and role for clinical profile and mortality in individuals with heart failure.Zeid et al., Clinical Research in Cardiology, 2024. doi.org/10.1007/s00392-023-02248-7
Normative Values of Short-Term Heart Rate Variability Parameters in Koreans and Their Clinical Value for the Prediction of Mortality.Lee et al., Heart, Lung & Circulation, 2018. doi.org/10.1016/j.hlc.2017.04.009

Version history

Version	Date	Rating	Change
1.0	October 24, 2026	Established	First published.

Rating history on the research desk: Established (September 29, 2026).

Cite this finding

KnowYourPrime Evidence Registry, Finding KYP-ER-0014, version 1.0, reviewed 2026-10-24. https://knowyourprime.com/evidence-normal-hrv-by-age

Machine-readable: JSON · Markdown · All findings

Research desk: the HRV research desk entry for this question, with every scored study and its role
Related finding: Wearable HRV Accuracy Against ECG (KYP-ER-0003)
Related finding: Overnight HRV Drop Before an Infection (KYP-ER-0013)
On this site: Is My HRV Normal for My Age? Reference Ranges by Age and Sex
On this site: What Is a Good HRV? There Is No Universal Number

This is KnowYourPrime's own assessment of the published evidence, rated under the KnowYourPrime evidence methodology. The rating is set by a fixed rule from the roles of the studies above and moves only when the evidence or the rule changes. Every change to the rating or the text is published as a new dated version. To report an error, write to corrections@knowyourprime.com.