What is a good HRV by age? The chart, and its limits
You glanced at your watch, saw an HRV of 28 ms, and looked up whether that was bad. Then you found a chart saying 60–100 ms is healthy, and now you feel worse than you did before you checked. That chart was probably built from young athletes. A good HRV by age looks very different at 52 than it does at 27, and the honest version of this answer has more caveats than most sites will give you. Here is what the published data actually shows, and what to do with it.
What HRV actually measures
Your heart does not beat like a metronome. HRV is the size of that wobble.
Between two beats there might be 0.90 seconds, then 0.86, then 0.93. Heart rate variability measures the variation in those gaps, in milliseconds. It reflects the balance between the two halves of your autonomic nervous system: the sympathetic side that speeds things up, and the parasympathetic side that slows them down. More variation generally means your nervous system is switching between them freely.
The most common measure on consumer devices is SDNN, the standard deviation of the intervals between normal beats. Apple Watch reports SDNN, and most of what lands in your Health app comes from overnight samples taken while you are still. Oura, Whoop, and Garmin often report RMSSD instead, a different calculation that produces different numbers. That alone makes cross-device comparison a dead end.
What a good HRV by age looks like
Here is the clearest dataset published on the question, and its numbers are lower than the internet’s.
A 2015 study of 1,906 healthy adults took five-minute resting ECG recordings and reported normative values by age band and sex.
| Age | SDNN, women (ms) | SDNN, men (ms) | RMSSD, women (ms) | RMSSD, men (ms) |
|---|---|---|---|---|
| 25–34 | 48.7 | 50.0 | 42.9 | 39.7 |
| 35–44 | 45.4 | 44.6 | 35.4 | 32.0 |
| 45–54 | 36.9 | 36.8 | 26.3 | 23.0 |
| 55–64 | 30.6 | 32.8 | 21.4 | 19.9 |
| 65–74 | 27.8 | 29.6 | 19.1 | 19.1 |
Two things stand out. Average SDNN roughly halves between the mid-twenties and the mid-seventies. And the male-female difference, real in the younger bands, disappears in the oldest ones.
A separate 2020 study in Frontiers in Aging Neuroscience followed 291 healthy adults aged 19–69 and found the same slope: mean SDNN fell from about 42 ms in the twenties to roughly 24 ms in the sixties. Different population, same direction.
So if you are 50 and reading 30 ms, you are sitting close to the published average for your age. The 60–100 ms figure circulating on fitness sites describes people two decades younger, often athletes.
Why the chart is the least useful part of this
Every number above comes with an error bar wider than most people expect.
In that 2015 dataset, the standard deviations run 12–21 ms. A woman aged 45–54 with an SDNN of 23 ms and one with 51 ms are both inside one standard deviation of the same average. Population norms describe groups. They do not grade individuals.
There is also no clinical target to hit. As Harvard Health notes, cardiologist Dr. Christopher Cannon points out that there are no guidelines or recommendations from professional cardiovascular societies about HRV, and no standardized definition of a high or low value. The Cleveland Clinic makes the same point more bluntly: variability that is normal in one person may not be normal in another.
Which leaves the only comparison that holds up: you, against you, last month. The same logic applies to resting heart rate, where the trend also carries more information than the reading.
What actually pushes your HRV down
Most single-night drops have a boring explanation.
- Alcohol. Usually the largest and most reliable overnight hit.
- Poor or short sleep, including a late bedtime at your usual wake time.
- A hard workout the previous day. This one is expected, not alarming.
- Illness, often a day or two before you feel symptoms.
- Acute stress: a deadline, a bad conversation, a sick parent.
Sustained low HRV is a different question. The Cleveland Clinic lists diabetes, high blood pressure, arrhythmia, asthma, anxiety, and depression among the conditions associated with lower variability. Untreated sleep apnea belongs on that list too, and it is one of the more common explanations in adults over 40, so it is worth knowing the signs of sleep apnea you can spot without a bed partner.
Note the word associated. Low HRV is not a diagnosis of any of these, and a normal HRV does not rule them out.
When it’s worth mentioning to a doctor
Three patterns are worth raising. Everything else can wait.
- A sustained drop from your own baseline, meaning several weeks rather than several days, with no obvious lifestyle explanation.
- A low trend alongside new symptoms: unusual fatigue, shortness of breath, palpitations, dizziness, or loud snoring with daytime sleepiness.
- A low trend plus a known condition you are already managing, such as hypertension or type 2 diabetes, where your clinician may read it as one more input.
Bring the trend, not the screenshot. A monthly average over six months tells a doctor something. Tuesday’s 24 ms does not. More of what is worth escalating, and what to leave alone, is in our wearables and Apple Health guides.
What Katika Care does about this: If you want a single place to keep all of this — your HRV and resting heart rate trend, your parent’s blood pressure log, your kid’s growth chart — Katika Care does that. It’s free, no ads, no data resale, and works alongside Apple Health or Health Connect.
A good HRV by age is a starting point, not a verdict. The useful way to hold this number is loosely. Learn roughly where your age band sits, learn where you personally sit inside it, then stop reading the daily figure and check the monthly one. HRV is a decent mirror for habits you already know you should change. It is a poor scoreboard, and an even poorer diagnosis.
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Frequently asked questions
What's a good heart rate variability number?
There isn't a universal one. HRV depends on your age, sex, fitness, sleep, and the device doing the measuring, and no cardiology society publishes a target. Published five-minute ECG norms put average SDNN near 50 ms for adults in their late twenties and closer to 30 ms after 55. Use those as context, not a grade. The number worth watching is your own average over a few weeks.
Is a low HRV something I should worry about?
One low night, no. HRV drops after poor sleep, alcohol, a hard workout, illness, or a stressful day, and it comes back. What matters more is a sustained drop from your own baseline that lasts a few weeks, especially alongside new symptoms like unusual fatigue, shortness of breath, or palpitations. That combination is worth a conversation with your doctor rather than more scrolling.
How is heart rate variability measured?
Clinically, with an ECG that times the gap between each heartbeat. Wearables estimate the same intervals optically at the wrist, using light to detect blood flow. Apple Watch reports SDNN, the standard deviation of those intervals, sampled periodically rather than continuously. Most of the readings in your Health app come from overnight samples taken while you are still, which is why HRV data looks sparse during the day.
Can I improve my heart rate variability?
Often, though it moves slowly. The habits associated with higher HRV are the unglamorous ones: consistent sleep, regular aerobic exercise, less alcohol, and managing stress. Harvard Health frames HRV as a way to see whether those changes are working rather than a target to chase. Give any change six to eight weeks before reading anything into the trend, and compare monthly averages instead of days.
Why is my HRV lower than my friend's?
Probably age and hardware. HRV declines across adulthood, and the gap between two healthy people the same age can still be large, because genetics and fitness both play a part. Different devices also compute HRV differently, so an Oura number and an Apple Watch number are not directly comparable. Comparing across people is the least informative thing you can do with this metric.