Reference charts
What Is a Good HRV? Normal HRV by Age
There is no universal good HRV number. The age table reports mean RMSSD from one 5-minute supine ECG study of healthy adults. A watch or ring uses a different window, sensor and algorithm, so its number will not match that table. The bands further down are consumer-facing illustrations, not validated health grades.
Updated . Educational reference, not medical advice.
What is a good HRV by age?
A good HRV depends on age, and there is no universal score. In one 5-minute supine ECG study of healthy adults, mean RMSSD was 42.9 ms in women and 39.7 ms in men at ages 25–34, and 19.1 ms in both sexes at ages 65–74 (Voss et al., 2015). Across short-term studies, the mean of published rMSSD averages was 42 ms, and those study means ranged from 19 to 75 ms (Nunan et al., 2010). Those figures are population references from ECG, not a wearable target and not a diagnosis.
RMSSD by age
Means and standard deviations from Voss et al. (2015), Tables 5 (women) and 7 (men). The cohort is 1,906 healthy adults in KORA S4 (Augsburg, Germany), ages 25–74. Each recording is a 5-minute supine ECG (leads II and V2, 500 Hz) after 5–10 minutes of rest. RMSSD follows the 1996 Task Force definition. An overnight watch or ring average is a different measurement. The longer discussion is the HRV reference chart by age.
| Age (years) | Women, mean RMSSD ± SD (ms) | Men, mean RMSSD ± SD (ms) | n (women / men) |
|---|---|---|---|
| 25–34 | 42.9 ± 22.8 | 39.7 ± 19.9 | 208 / 330 |
| 35–44 | 35.4 ± 18.5 | 32.0 ± 16.5 | 259 / 292 |
| 45–54 | 26.3 ± 13.6 | 23.0 ± 10.9 | 158 / 235 |
| 55–64 | 21.4 ± 11.9 | 19.9 ± 11.1 | 95 / 183 |
| 65–74 | 19.1 ± 11.8 | 19.1 ± 10.7 | 62 / 84 |
Source: Voss et al., PLOS ONE 2015, Tables 5 and 7 (doi:10.1371/journal.pone.0118308). Five-minute supine ECG after 5–10 minutes of rest. Values are mean ± standard deviation, in milliseconds.
Illustrative RMSSD bands
| Illustrative RMSSD band (ms) | Non-clinical label | Why the number is insufficient |
|---|---|---|
| <20 | Low | Can occur in healthy people or with many transient and chronic factors; it is not diagnostic by itself |
| 20–39 | Below Average | May reflect sedentary lifestyle, chronic stress, poor sleep, or normal aging (common in adults over 55); room for improvement |
| 40–59 | Average | May fall near some study medians, but does not establish normal autonomic function |
| 60–99 | Above Average | Good parasympathetic tone; typical for physically active adults under 45; reflects positive recovery |
| 100–150 | Excellent | May occur in younger or trained people; does not prove recovery capacity |
| >150 | Very High | May reflect physiology, ectopic beats, artifact or processing; verify unexpected values rather than assigning a grade |
Source: Illustration only. These cutoffs are not the Voss 2015 means in the age table, and they are not diagnostic grades.
How to read this chart
The age table is a 5-minute supine ECG mean, split by sex. The bands in this section are illustrations. They are not those study means, and a value that a consumer chart calls low can be typical for an older adult in the KORA data.
HRV scores reported by consumer wearables are typically RMSSD measured during sleep (nocturnal HRV) or upon waking (morning readiness HRV). These values can differ significantly from clinical HRV assessments performed during controlled supine rest, making direct comparison between devices and clinical studies difficult. Each device uses proprietary algorithms, and values from different brands should not be compared directly. Overnight heart rate is reported the same way; see sleeping heart rate by age and gender for large ring-data tables. How published wearable HRV studies compare with a reference is collected on the HRV accuracy board. The formula itself is the RMSSD algorithm, and the plain-language definition is what HRV measures.
The single most important HRV metric is your personal baseline and how your daily readings compare to your rolling average. A 15–20% drop from your 7-day average may indicate insufficient recovery, oncoming illness, or acute stress, even if the absolute number is within a "normal" range. Conversely, a consistently rising HRV trend over weeks to months is a positive indicator of improving fitness, stress management, and cardiovascular health.
Factors that acutely affect HRV include alcohol (reduces HRV for 12–48 hours), sleep quality and duration, exercise timing and intensity, hydration status, caffeine, stress, and late meals. For the most consistent readings, measure HRV at the same time each day (ideally upon waking), after a consistent sleep schedule, and before consuming caffeine. A 7-day or 30-day rolling average provides a more reliable picture than any single daily reading. If your HRV is consistently in the "Low" category for your age and you are under 50, consider discussing with your healthcare provider, as persistently low HRV is associated with increased cardiovascular risk and all-cause mortality.
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Frequently asked questions
What is a good HRV by age?
In healthy adults recorded with a 5-minute supine ECG, mean RMSSD was 42.9 ms in women and 39.7 ms in men at ages 25–34, 35.4 and 32.0 ms at 35–44, 26.3 and 23.0 ms at 45–54, 21.4 and 19.9 ms at 55–64, and 19.1 ms in both sexes at 65–74 (Voss et al., 2015). A review of short-term studies found a mean rMSSD of 42 ms, with study means from 19 to 75 ms (Nunan et al., 2010). There is no universal good score. A wearable overnight number is a different measurement, and one reading is not a diagnosis.
Is 37 a low HRV?
About 37 ms is not a low cutoff. It sits near the 42 ms mean of short-term rMSSD study averages in healthy adults (Nunan et al., 2010; those study means ranged from 19 to 75 ms). In the KORA 5-minute ECG series it is close to the mean at ages 25–34 (39.7 ms in men, 42.9 ms in women) and above the means from age 45 onward (19.1 to 26.3 ms). Age, the recording and the device all change the comparison. One number is not a diagnosis.
Is an HRV of 40 considered normal?
About 40 ms is close to the short-term rMSSD mean of 42 ms across studies of healthy adults (Nunan et al., 2010) and to the ages 25–34 means in a 5-minute supine ECG study (39.7 ms in men and 42.9 ms in women; Voss et al., 2015). It is not a normal range for every age or every device. In that same ECG study, mean RMSSD at ages 55–64 was 21.4 ms in women and 19.9 ms in men. Watches and rings often average overnight pulse intervals, which are not the same as a 5-minute lab ECG.
Why is my HRV so low even though I'm fit?
Fitness is only one influence. HRV also falls with age, and a single low reading can follow poor sleep, alcohol, illness, stress or a different recording window. A ring or watch reports pulse-rate variability, not an ECG RMSSD, and brands do not match each other. Shaffer and Ginsberg (2017) note that two artifacts inside a 5-minute segment can distort RMSSD. A fit person can still sit below a population mean. Compare the same device with your own recent baseline, and talk with a clinician about symptoms rather than treating one low value as a diagnosis.
What is a good HRV score for my Apple Watch / Whoop / Oura Ring?
Devices differ in timing, artifact handling and summary methods, so values are not directly comparable across brands. No universal RMSSD interval defines health for adults aged 25–55. Compare like-for-like readings with your own baseline and discuss symptoms or unexpected changes with a clinician.
Can HRV be too high?
Extremely high HRV (RMSSD >150 ms) is usually a sign of excellent fitness, especially in young endurance athletes. However, in rare cases, very high HRV can indicate pathological vagal tone or be associated with conditions like vasovagal syncope. If very high HRV is accompanied by frequent fainting, dizziness, or unexplained fatigue, medical evaluation is warranted.
How quickly can I improve my HRV?
Most people see measurable HRV improvements within 4–8 weeks of consistent aerobic exercise (150+ min/week), improved sleep hygiene, and stress management. The fastest improvements come from eliminating HRV-suppressing habits: reducing alcohol intake, improving sleep consistency, and managing acute stress. Meditation and deep breathing exercises can acutely increase HRV within a single session, while sustained structural improvements require weeks of consistent lifestyle changes.
References
- Voss A, Schroeder R, Heitmann A, Peters A, Perz S. Short-term heart rate variability—influence of gender and age in healthy subjects. PLoS One. 2015;10(3):e0118308. doi.org/10.1371/journal.pone.0118308
- Nunan D, Sandercock GRH, Brodie DA. A quantitative systematic review of normal values for short-term heart rate variability in healthy adults. Pacing Clin Electrophysiol. 2010;33(11):1407–1417. doi.org/10.1111/j.1540-8159.2010.02841.x
- Shaffer F, Ginsberg JP. An overview of heart rate variability metrics and norms. Front Public Health. 2017;5:258. doi.org/10.3389/fpubh.2017.00258
- Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Heart rate variability: standards of measurement, physiological interpretation, and clinical use. Circulation. 1996;93(5):1043–1065. doi.org/10.1161/01.CIR.93.5.1043