Average HRV by age (RMSSD, resting overnight):
| Age | Low | Median | High |
|---|---|---|---|
| 20–29 | 35 ms | 60 ms | 100+ ms |
| 30–39 | 30 ms | 50 ms | 85 ms |
| 40–49 | 25 ms | 40 ms | 70 ms |
| 50–59 | 20 ms | 35 ms | 55 ms |
| 60+ | 18 ms | 28 ms | 45 ms |
SDNN (Apple Watch) values run roughly 1.5–2× higher than RMSSD. Use the median as a rough orientation, not a target.
The short answer
A “good” HRV is yours, on a good day, when you’ve been sleeping, breathing slowly, and recovering well. The only comparison that matters is you-now versus you-last-month.
Why HRV benchmarks are mostly noise
HRV varies dramatically between people — and even between devices on the same person. Three things conspire to make absolute numbers misleading:
- Different metrics. SDNN (Apple Watch) and RMSSD (Oura, Whoop) measure different things, on different timescales, and produce different numbers. SDNN tends to be 2–3× higher than RMSSD for the same person.
- Different times.Daytime measurements are dramatically lower than overnight measurements. Standing measurements are lower than lying-down. A “your HRV is 25” reading is meaningless without context.
- Different bodies. Genetic variation in baseline HRV is wide. A naturally calm person with an HRV of 40 may be healthier than an athlete with an HRV of 80 — what matters is where you sit in your own distribution.
Approximate norms, with caveats
If you must compare, these are the ranges most studies converge on for resting overnight RMSSD by age. Everyone is wider than the ranges suggest.
- 20s — 50 to 100 ms
- 30s — 40 to 80 ms
- 40s — 30 to 65 ms
- 50s — 25 to 55 ms
- 60s+ — 20 to 45 ms
SDNN ranges are roughly 1.5–2× higher. Your Apple Watch nightly SDNN of, say, 55 ms in your forties is firmly in the “normal, healthy, plenty of room to grow” band.
The comparison that actually matters
Forget the population. Compare yourself to yourself.
Take a seven-day rolling average. Watch it move over weeks of intentional intervention — slower breathing, better sleep, less alcohol. If that average is trending up, the intervention is working. If it’s trending down, something has changed and it’s worth asking why.
A 10 percent week-over-week change in your seven-day average is a big signal. A 5 percent change in either direction is meaningful. Single-day spikes mean nothing.
When to be concerned
A sustained drop in HRV — say, a 20 percent decline in your seven-day average over two weeks — usually means one of: developing illness (often viral, often before symptoms), chronic stress accumulation, sleep debt, or training overload. It is not a diagnostic tool. It is a signal to investigate.
Conversely, a sustained upward trend after weeks of slow-breathing practice is the most reliable confirmation that the practice is working at the physiological level — not just at the feels-good-after-sessions level.