No universal target: normal HRV covers a wide range, and two healthy people can differ several-fold.
Age matters most: median RMSSD roughly halves between your early 20s and your late 50s.
Women run slightly higher: by about 5 ms on average between ages 20 and 45, with the gap closing after 60.
Compare like with like: Apple Watch reports SDNN, while most other wearables report RMSSD, so their numbers aren't interchangeable.
Your trend beats the population: a steady or rising HRV against your own baseline is the best sign. A persistently low HRV for your age is worth looking into.
What does HRV measure?
Heart rate variability is the variation in time between one heartbeat and the next, measured in milliseconds. A healthy heart doesn't tick like a metronome. It speeds up slightly when you breathe in and slows when you breathe out.
That variation is controlled by your autonomic nervous system. Your parasympathetic ("rest and digest") branch increases HRV, and your sympathetic ("fight or flight") branch reduces it. A higher HRV for your age generally means your body is recovered and able to adapt to stress.
If your HRV has dropped recently, read our guide on Why your HRV might be going down
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What is a normal HRV range for adults?
The most widely cited normal values come from a systematic review that pooled 44 studies [1]. Together they included 21,438 healthy adults aged 18 and over. Each study measured HRV at rest over a short recording, usually 5 minutes lying down, using the standard international method.
Across these studies, the average RMSSD was 42 ms, with study averages ranging from 19 to 75 ms. The average SDNN was 50 ms, ranging from 32 to 93 ms.
RMSSD (root mean square of successive differences) measures how much each gap between heartbeats differs from the one before. It mainly reflects your parasympathetic "rest and digest" activity, and it's the measure most wearables report.
SDNN (standard deviation of NN intervals) measures how spread out all the gaps between heartbeats are across the whole recording. It reflects both branches of the nervous system, and it gets larger the longer the recording.
These figures mix all adult ages and aren't split by age or sex, so treat them as a broad guide rather than a target. The review also found large differences between individuals, even among healthy people. For values matched to your age and sex, see the chart below.
Normal HRV ranges by age and sex
This table shows the median RMSSD in men and women from the lifelines Cohort Study in the Netherlands. It measured RMSSD in 84,772 healthy people ages 13 to 75. As we age our HRV falls until about age 60 where it levels off.
Age | Women: median RMSSD (normal range) | Men: median RMSSD (normal range) |
20–24 | 52.1 ms (11.3–205.5) | 47.6 ms (9.6–174.0) |
25–29 | 47.5 ms (11.5–180.7) | 42.3 ms (10.1–172.7) |
30–34 | 42.3 ms (11.5–161.0) | 36.9 ms (10.2–140.8) |
35–39 | 37.9 ms (10.8–141.9) | 32.8 ms (8.6–123.8) |
40–44 | 33.9 ms (9.7–123.7) | 29.0 ms (8.1–105.5) |
45–49 | 29.2 ms (8.3–109.5) | 26.0 ms (7.1–95.5) |
50–54 | 26.6 ms (7.5–96.3) | 23.7 ms (6.7–87.5) |
55–59 | 22.5 ms (6.7–83.6) | 21.0 ms (5.5–89.5) |
60–64 | 20.5 ms (5.5–79.3) | 19.1 ms (4.8–86.6) |
65–69 | 17.8 ms (5.0–83.0) | 17.7 ms (4.9–110.5) |
70–74 | 18.3 ms (5.0–115.8) | 16.0 ms (4.7–161.9) |
75+ | 16.1 ms (3.5–106.2) | 14.9 ms (3.7–130.3) |
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Why HRV varies between people
Two healthy people of the same age can have very different HRV. Several things set your baseline:
Genetics: genes explain roughly 13–23% of the variation in HRV [4]. Part of your baseline is simply inherited.
Age: HRV declines across adult life, as the chart above shows.
Sex: women tend to have slightly higher parasympathetic activity until around 60 [2, 3].
Fitness: regular aerobic exercise is linked to higher HRV. In a study of 8 million wearable users, more physical activity went with higher HRV, although this shows association rather than cause [5].
Breathing: slow breathing raises HRV in the moment, which is why readings taken during guided breathing look higher.
Health conditions and medicines: high blood pressure, diabetes and some medicines can lower HRV. Beta-blockers can raise it.
This is why comparing your number with a friend's, or with someone online, tells you very little. Comparing it with your own past readings tells you much more.
Why your HRV looks different on each wearable
If you've switched devices and your HRV suddenly jumped or dropped, the device is the likely reason. Wearables don't all measure HRV the same way.
Device | Metric reported | When it measures |
Apple Watch | SDNN | Short readings through the day and night |
Oura, WHOOP, Garmin, Fitbit | RMSSD | Mainly overnight, during sleep |
Due to RMSSD and SDNN measuring different things (explained above), an Apple Watch number can't be compared directly with an Oura or Garmin number. RMSSD is the measure most researchers use for day-to-day tracking.
If you switch devices, give the new one 2–4 weeks to build a fresh baseline before comparing.
Time of day matters too. HRV peaks in the early morning and falls through the day [5]. A night-time reading and an afternoon reading can differ a lot, even from the same device.
Is a higher HRV always better?
Usually, yes, within your own normal range. A higher resting HRV for your age generally reflects good recovery and a healthy, adaptable nervous system. Endurance athletes often have high values.
There are exceptions. A very high or suddenly erratic HRV, especially if it's out of keeping with how you feel, can come from irregular heartbeats rather than good health. Extra beats (ectopics) and atrial fibrillation both make the gaps between beats more uneven, which pushes the HRV figure up.
Speak to a doctor if a sudden jump in HRV comes with palpitations, a fluttering or irregular pulse, dizziness or breathlessness. Some wearables can also flag a possible irregular rhythm, and that alert is worth acting on.
How to find your own baseline
Your personal baseline is more useful than any population chart. To find it:
Use the same device and wear it the same way, snug on the wrist or with a chest strap.
Measure at the same time each day. Overnight readings or a reading just after waking work best.
Track for 2–4 weeks before drawing conclusions. Most apps build your baseline automatically over this period.
Look at the weekly average, not single days. One low reading after a late night or a hard workout is normal.
Note what's going on: training, alcohol, illness, stress, travel and, for women, where you are in your cycle.
Once you know your baseline, a good HRV is one that stays within it or slowly rises.
Is your HRV too low?
A low HRV matters most when it's low for your age and stays low. A large meta-analysis of 38,008 people found that HRV predicted death from any cause, in both healthy and clinical populations [6]. People whose 5-minute RMSSD was in the lowest quarter had a 56% higher risk of death.
That's a population link, not a verdict on you. A single low reading tells you very little. These studies are also observational, so they don't show that raising your HRV lowers your risk.
It's worth speaking to a doctor if:
your HRV has stayed well below your usual range for more than 2 weeks without an obvious reason
it's consistently near the bottom of the normal range for your age
a low HRV comes with symptoms such as fatigue, breathlessness, palpitations, chest pain or low mood
Low HRV is linked to conditions such as high blood pressure and diabetes [7, 8], which a blood test and a blood pressure check can pick up.
Frequently asked questions
Is 30 a good HRV? An RMSSD of 30 ms is close to the median for healthy adults in their 40s [2]. It's normal for most people in midlife. In your 20s it's below average but still within the normal range.
Is 50 a good HRV? Yes. An RMSSD of 50 ms is above the median for every adult age group except women aged 20–24, who sit at about 52 ms [2].
Is 100 a good HRV? An RMSSD of 100 ms is high, but it's within the normal range for most healthy adults under 50 and common in endurance athletes. If your HRV jumps to this level suddenly, or you notice an irregular heartbeat, check with a doctor.
What is a good HRV for a woman? In healthy women, median RMSSD falls from about 52 ms in the early 20s to about 34 ms in the early 40s and 22 ms in the late 50s [2].
What is a good HRV for a man? In healthy men, median RMSSD falls from about 48 ms in the early 20s to about 29 ms in the early 40s and 21 ms in the late 50s [2].
What is a good HRV while sleeping? There are no agreed clinical norms for overnight wearable HRV. Overnight values are measured differently from the clinical studies above, so the best guide is your own device's baseline over several weeks.
The bottom line
A good HRV isn't a single number. Use the age and sex chart to see roughly where you sit, then focus on your own trend. A steady or rising HRV within your normal range is a good sign. A persistently low HRV for your age, especially with symptoms, is worth discussing with a doctor.
References
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:10.1111/j.1540-8159.2010.02841.x
Tegegne BS, Man T, van Roon AM, Snieder H, Riese H. Reference values of heart rate variability from 10-second resting electrocardiograms: the Lifelines Cohort Study. Eur J Prev Cardiol. 2020;27(19):2191–2194. doi:10.1177/2047487319872567
Koenig J, Thayer JF. Sex differences in healthy human heart rate variability: a meta-analysis. Neurosci Biobehav Rev. 2016;64:288–310. doi:10.1016/j.neubiorev.2016.03.007
Singh JP, Larson MG, O'Donnell CJ, et al. Heritability of heart rate variability: the Framingham Heart Study. Circulation. 1999;99(17):2251–2254.
Natarajan A, Pantelopoulos A, Emir-Farinas H, Natarajan P. Heart rate variability with photoplethysmography in 8 million individuals: a cross-sectional study. Lancet Digit Health. 2020;2(12):e650–e657. Full text
Jarczok MN, Weimer K, Braun C, et al. Heart rate variability in the prediction of mortality: a systematic review and meta-analysis of healthy and patient populations. Neurosci Biobehav Rev. 2022;143:104907. doi:10.1016/j.neubiorev.2022.104907
Schroeder EB, Liao D, Chambless LE, et al. Hypertension, blood pressure, and heart rate variability: the ARIC study. Hypertension. 2003;42(6):1106–1111.
Hillebrand S, et al. Prediabetes, type 2 diabetes and heart rate variability. Diabetes Care. 2020
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