RingConn sells three rings, the Gen 3, the Gen 2 and the cheaper Gen 2 Air, and all three record HRV and share one app. They differ in battery life, materials and extras: the Gen 3 adds blood pressure trends and vibration alerts, and the Gen 2 Air leaves out sleep apnea monitoring (RingConn Support, Gen 3).
Documentation checked: 22 October 2026. RingConn updates its app and its help pages often, so details can change.
What HRV number RingConn shows
The ring shines light into the finger and times each pulse, a method called photoplethysmography PPG An optical method that shines light into the skin and detects the pulse of blood with each heartbeat. Most watches, rings and phone-camera apps use it to estimate HRV. More about PPG (PPG). RingConn’s comparison page lists HRV as “24/7 Monitoring” on the Gen 3, Gen 2 and Gen 2 Air, alongside heart rate and blood oxygen; it measures breathing rate Breathing rate How many breaths you take a minute. It moves HRV on its own: slower, deeper breathing makes the beat-to-beat swing larger, and below about 9 breaths a minute it shifts from the HF band into LF. More about Breathing rate only at night (RingConn, compare).
RingConn’s guide to its scores says its “HRV terminology uses RMSSD RMSSD Root mean square of successive differences: an HRV metric built from how much each heartbeat interval differs from the next, in milliseconds. It mainly reflects vagal activity. More about RMSSD ” (RingConn, health scores), the standard measure of how much one beat-to-beat gap differs from the next (Task Force, 1996). The value is in milliseconds.
RingConn does not publish the window. For heart rate, its support pages spell it out: the Vital Signs chart updates every 5 minutes, and the sleep chart’s average runs “from bedtime to wake-up” (RingConn Support, Gen 2). We found nothing similar for HRV: no sampling interval, and no statement of which part of the night a nightly value covers. That window matters, because a whole-night average, a deep-sleep value and a 4-hour value differ on the same night (why Oura and WHOOP show different HRV). For the same reason, we left RingConn out of the simulated night on our other device pages.
RingConn’s own advice is to compare like with like: “Avoid comparing an overnight HRV value directly with an unrelated daytime HRV measurement” (RingConn, HRV guide).
The Stress Index
RingConn builds one score on HRV, the Stress Index. The ring’s software estimates it from heart rate and the intervals between beats and scores it from 1 to 100 (RingConn, stress guide). RingConn calls the bands “RingConn-specific”, says its Normal band is “not a universal medical reference”, and warns that a score of 50 does not mean an HRV of 50 ms.
What is in a readiness score?
From the makers' own documentation
- HRV : named by the maker Heart rate variability from the ring’s optical sensor: "A Stress Index of 50 is not an HRV of 50 milliseconds."
- Resting heart rate : not named Not named by the maker.
- Breathing rate : not named Not named by the maker.
- Sleep : not named Not named by the maker.
- Temperature : not named Not named by the maker.
- Activity or load : not named Not named by the maker.
Also: Heart rate at the time: the software "uses heart-rate and beat-interval information to estimate a stress index". Resting heart rate is not named.
RingConn's Stress Index names 1 of the six inputs, HRV, and others beyond them. RingConn publishes the four bands and calls them "RingConn-specific". It gives no formula.
Source: RingConn Stress Index: scores, HRV and daily patterns (RingConn)
A list of scores, one per device, with six inputs for each: HRV, resting heart rate, breathing rate, sleep, temperature and activity or load. RingConn's Stress Index names 1 of the six inputs, HRV, and others beyond them. RingConn publishes the four bands and calls them "RingConn-specific". It gives no formula.
RingConn’s guide mentions other summaries, such as Wellness Balance, Lifestyle or Recovery, and says their labels “may differ between app versions”. It gives no weights for them (RingConn, health scores). What is an HRV score out of 100 explains why such scores cannot be compared across brands, and is Garmin stress the same as HRV covers a similar score.
Where your RingConn HRV goes
RingConn’s product pages group HRV with heart rate and blood oxygen under Vitals, and its support pages put the heart rate charts on the Insights page, under the Vital Signs tab (RingConn Support, Gen 2). We found no RingConn page that names the HRV screen itself.
Getting HRV out of the app is harder. RingConn documents two links:
- Apple Health. Turn it on under Me, App Settings, Data Management, Connect to Apple Health. RingConn lists what syncs and how often: steps, calories, blood oxygen and heart rate about every 30 minutes; sleep, height and weight once the data is ready. HRV is not on the list (RingConn Support, Gen 3).
- Health Connect on Android. RingConn stopped syncing to Google Fit on 1 October 2025 and moved to Health Connect, which receives activity, sleep, resting and average heart rate, blood oxygen, height and weight. On HRV, RingConn says: “There is currently an algorithm compatibility issue, so we do not support syncing your HRV data at this time” (RingConn, Health Connect). Its July 2026 troubleshooting guide still says the same (RingConn, Health Connect sync).
- The ring Reads the pulse with light at the finger. HRV is recorded around the clock on all three models.
- RingConn app Shows HRV, and a Stress Index from 1 to 100 built on heart rate and HRV. No subscription.
- Outside the app
- Apple Health No HRV
- Steps, calories, blood oxygen, heart rate, sleep. HRV not listed.
- Health Connect No HRV
- Activity, sleep, heart rate, blood oxygen. HRV not synced.
Three steps joined by arrows. One: the ring, which reads the pulse with light at the finger and records HRV around the clock. Two: the RingConn app, which shows HRV and a Stress Index from 1 to 100 built on heart rate and HRV, with no subscription. Three: two places outside the app. Apple Health receives steps, calories, blood oxygen, heart rate, sleep, height and weight, and RingConn does not list HRV. Health Connect on Android receives activity, sleep, heart rate, blood oxygen, height and weight, and RingConn says HRV is not synced because of an algorithm compatibility issue.
In practice, you keep your HRV history in RingConn’s app and account. RingConn ties data to the account rather than the ring, so it carries over when you move to a new model (RingConn Support, Gen 3). An app that reads HRV from Health Connect will not see RingConn’s.
Does RingConn need a subscription?
No. RingConn’s comparison page lists the subscription fee as “No” for all three rings, and the Gen 3 and Gen 2 pages say “No Subscription Required” (RingConn, compare). HRV and the stress score are in the free app. RingConn’s US store listed these starting prices on 22 October 2026:
| Option | Device price | Subscription for HRV | 3 years |
|---|---|---|---|
| RingConn Gen 2 Air | $199 | None | $199 |
| RingConn Gen 2 | $299 | None | $299 |
| RingConn Gen 3 | $349 | None | $349 |
| WHOOP One | Included | $199 a year | $597 |
Starting prices from each maker’s US page (see Sources); some RingConn finishes cost more. We read the WHOOP price on 21 October 2026.
What HRV tracking costs over three years
US prices, 21 – 22 October 2026
Each price, and the page it was read on, is in the table.
A step chart of the money spent on HRV tracking from the first day to the end of year 3, one line per option. A device bought outright is a flat line; a yearly membership steps up at the start of each year. RingConn Gen 2 Air: $199 on the first day, $199 by the end of year 3. RingConn Gen 2: $299 on the first day, $299 by the end of year 3. RingConn Gen 3: $349 on the first day, $349 by the end of year 3. WHOOP One membership: $199 on the first day, $597 by the end of year 3.
Oura is the closer comparison, since it is also a ring, but Oura’s store showed us another country’s prices, so its ring is not in the chart. Its membership costs $5.99 a month or $69.99 a year in the US, after one included month, and without it the app shows the three daily scores but not the nightly HRV number (Oura Member Care). Cheapest HRV tracking compares more options.
How accurate is RingConn HRV?
We found one peer-reviewed study of a RingConn ring. Tao and colleagues recorded 64 athletes aged 13 to 26, from rifle, pistol and archery squads, for 10 minutes while they sat still within 5 minutes of a training session, wearing a RingConn Gen 2 on the left index finger and a Polar H10 chest strap at the same time. The researchers detected each beat themselves, in the ring’s raw pulse signal and the strap’s ECG ECG A recording of the heart's electrical activity, taken with electrodes on the skin. ECG-based RR intervals are the reference standard for measuring HRV. More about ECG , worked out RMSSD in 90-second windows and compared each person’s averages. They dropped 12 of the 384 windows (3.1%) because the ring’s signal was unusable (Tao and colleagues, 2026):
- RMSSD: the ring read 3.237 ms higher on average (the bias), with 95% limits of agreement from −8.591 to 15.065 ms and an average absolute error of 4.620 ms (intraclass correlation 0.9449).
- SDNN SDNN The standard deviation of all NN intervals in a recording, in milliseconds. It measures overall variability, and its value depends strongly on how long the recording lasts. More about SDNN : closer, with a bias of 1.791 ms and limits from −3.107 to 6.690 ms.
The authors call RMSSD agreement “good but had wider limits of agreement, indicating that small within-athlete changes should be interpreted more cautiously.”
How far one reading can sit from the reference
Validation tracker
Difference from the reference in RMSSD (ms), as each paper reports it
The RingConn row is the one study of a RingConn ring we found: 64 athletes sitting still after training, with RMSSD worked out by the researchers from the ring’s raw pulse signal, recorded with research firmware RingConn supplied, and averaged over each person’s 90-second windows. Three of its authors work for RingConn or a company involved in developing the ring. In that study the ring read higher than the strap on average. The Oura rows are the app’s own overnight number. Papers differ on which device they subtract from which, so compare the widths of the bars rather than the side of zero they fall on.
Sources: Johansson and colleagues, 2026, Tao and colleagues, 2026, Cao and colleagues, 2022, Miller and colleagues, 2022. Every study we have checked, with its numbers, is in the device validation tracker.
A chart with one horizontal bar per device and study, from the device validation tracker, on a scale in milliseconds with zero marked. Polar H10 (Reclined, against a lab ECG; Johansson and colleagues, 2026): bias 0.4 ms, limits −3.3 to 4.0 ms. RingConn Gen 2 (Seated after training, beats against an H10; Tao and colleagues, 2026): bias 3.237 ms, limits −8.591 to 15.065 ms. Oura Ring (Overnight at home, app value against an ECG; Cao and colleagues, 2022): bias −15.88 ms, limits −33.29 to 1.53 ms. Oura Ring Gen 2 (One night in a sleep lab, app value; Miller and colleagues, 2022): bias −10.2 ms, limits −87.4 to 67.0 ms. The RingConn row is the one study of a RingConn ring we found: 64 athletes sitting still after training, with RMSSD worked out by the researchers from the ring’s raw pulse signal, recorded with research firmware RingConn supplied, and averaged over each person’s 90-second windows. Three of its authors work for RingConn or a company involved in developing the ring. In that study the ring read higher than the strap on average. The Oura rows are the app’s own overnight number. Papers differ on which device they subtract from which, so compare the widths of the bars rather than the side of zero they fall on.
Read the result with its conditions. RingConn and a company involved in developing the ring supplied the rings, “customized research firmware” and data export. Three of the seven authors work for them and helped with the recording and the signal processing; the paper says the companies had no right to block publication. The firmware recorded the ring’s light signal 100 times a second and exported it raw, a setup that, in the authors’ words, “may differ from routine consumer-firmware operating modes”. So the study tested the ring’s sensor, and the HRV number the app shows was not part of it. Sitting still for 10 minutes is also the easy case for an optical sensor, and the study did not test sleep.
RingConn’s Gen 3 page claims a mean absolute error for HRV of under 3.5 ms (RingConn, Gen 3). It names no HRV measure, conditions or reference, and we found no study behind it, so we read it as a marketing figure. The one published study found an average absolute error of 4.620 ms, though it may not measure the same thing. No RingConn ring was in the independent overnight studies in the device validation tracker. In one of them, the Oura Ring Gen 4’s average error in overnight RMSSD against a chest strap was 5.96% (Dial and colleagues, 2025).
How to read RingConn’s numbers
- Read weeks, not days. Even sitting still, one person’s RMSSD from the ring could differ from the strap’s by up to about 15 ms, within limits of agreement nearly 24 ms wide. A change of a few milliseconds from one day to the next tells you little.
- Keep the fit the same. RingConn’s support pages suggest a snug fit with the sensor on the pad of the finger, and recommend the index finger “for a more stable signal” (RingConn Support, Gen 2). Pick a finger and stay on it.
- Do not read the stress score as HRV. It mixes in heart rate and has its own scale.
- Start a new series after a change. A new model or an app update can shift the values; see can a software update change my HRV.
- Compare RingConn only with itself. Without a published window, its number cannot be matched to an Oura, WHOOP or Garmin value, or to a morning chest-strap reading (overnight vs morning HRV). HRV by device lists what each brand measures.
RingConn or Oura for HRV?
Both are rings that read the pulse at the finger. Oura publishes its window, the average of 5-minute samples taken during sleep, and has independent overnight evidence behind it; read the Oura guide. RingConn costs nothing after the ring and records around the clock, but publishes no window and has one study, of athletes sitting after training, partly by its own staff. If the accuracy of the overnight number matters most to you, Oura has more evidence, though its results vary from study to study. If you want a trend with no running cost, RingConn gives you one, as long as you read it against itself.
When to talk to a doctor
RingConn states that its rings are “not a medical device” and are not for diagnosing any condition (RingConn, Gen 3 manual), and its stress score is not a medical test. Talk to a doctor if low HRV or a run of high stress readings comes with feeling unwell, lasting fatigue, palpitations, dizziness, fainting or chest pain, whatever the number says.