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# Night Heart Rate: I Separated the Good from the Bad in 8 Smart Rings
- URL: https://www.lordofthesmartrings.com/smart-rings-night-heart-rate-test/
- Published: 2026-10-22T06:11:49.000Z
- Updated: 2026-10-22T06:11:49.000Z
- Description: Seven nights, eight smart rings and a chest strap as the referee. Five rings recorded my night heart rate reliably and earn a recommendation. Three think I'm running up the stairs in my sleep — I wouldn't buy those.
- Author: LORDoftheSMARTRINGS
- Tags: smart ring, heart rate, comparison, testing, oura5, Ultrahuman PRO, ultrahuman air, RingConn Gen 3, helio, Circular 2, Muse, 🏆  Best smart ring, 💍Circular Smart Rings, 💍Oura Ring Gen 3 & 4 & 5, 💍 RingConn Smart Ring, 💍Ultrahuman AIR & PRO

**It's 12:54 a.m. and I'm fast asleep.** My Oura says my heart is beating 46 times a minute. At the exact same moment, the Circular Ring 2 says 73\. And the Muse Ring One? 96 — as if I were power-walking up the stairs.

So which one is telling the truth? There's only one way to find out: **a proper reference.**

There are so many smart rings out there right now that even I struggle to keep track — and I'm literally the Lord of the Smart Rings. So I decided to **find out which ones are actually worth your money**. For seven nights I slept with eight smart rings (yes, I'm officially running out of fingers) plus a chest strap as the referee (not exactly comfy, would not recommend), and sorted them into two groups:

> The ones that **can** and the ones that **can't** **measure the most basic thing of all: how fast my heart beats at night.**

Along the way, we'll hit two surprises. When the "bad" rings get it right, they're almost as accurate as the good ones — something else trips them up. And the ring that logs your heart rate most often finished dead last.

📹

****Prefer video over text? Watch it** [▶️ YouTube](https://www.youtube.com/watch?v=hV%5FxVMhw-Tg&ref=lordofthesmartrings.com)

Whether you're shopping for a ring or already wearing one, by the end you'll know whether you can trust its night-time numbers. And at the very end, I'll reveal who won the whole thing.

## 📌 Heart rate is the foundation of sleep, HRV and your morning score

Why night heart rate? Because it's not just one number out of many. It's the **base of the pyramid** — almost everything your smart ring (or any wearable, really) shows you in the morning is built on it:

> [View this post on Instagram](https://www.instagram.com/p/Del5R7Am6Vb/?utm%5Fsource=ig%5Fembed&utm%5Fcampaign=loading)
> 
> [A post shared by Lord (@lordofthesmartrings)](https://www.instagram.com/p/Del5R7Am6Vb/?utm%5Fsource=ig%5Fembed&utm%5Fcampaign=loading)

The higher you go up the pyramid, the more estimates and the less certainty. And above all: **an error at the base travels all the way to the top.** If a ring is off by ten beats, how is it supposed to calculate trustworthy derived metrics and scores? And could errors like that even feed orthosomnia?

[Orthosomnia — the wearable sickness. Do you have it?For seven years I opened Oura every morning like a report card. Then I learned what I was doing had a name — orthosomnia.![](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/icon/favicon-ea0fd378-6dba-4eec-8e6a-f9c278af9d4f.ico)LordOfTheSmartRingsLORDoftheSMARTRINGS![](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/thumbnail/Orthosomnia_thumb_B_EN-9da7e0af-95e8-410c-b932-44a087bdb1d4.jpg)](https://www.lordofthesmartrings.com/orthosomnia-wearable-sleep-tracker-obsession/)

To be fair, measuring heart rate from your finger is tough for an optical sensor. The ring shines light into your skin and, from the light that bounces back, estimates how the blood volume in your vessels changes (photoplethysmography, or PPG). A bit of movement, a ring that's loose or has slipped, or cold fingers — and the signal gets noisy, which leads to errors.

**On the other hand, night is the easiest possible job for optics.** I'm lying still, and my heart rate is slow and steady.

And that's not just my gut feeling. Independent studies confirm that optical sensors measure resting heart rate reliably…

#### Studies

Plews, Altini et al. (2017): 29 people at rest, finger optics (smartphone camera) vs a chest strap and ECG. Measured HRV — even more demanding than heart rate itself — matched the ECG practically perfectly (correlation 1.00).  
  
Study in IJSPP.Cao et al. (2022): 35 people, a night at home, Oura ring vs ECG. Heart rate in five-minute segments correlated at 0.99, and the nightly average was off by just 0.4 beats.   
  
Study in JMIR.Dial et al. (2025): 13 people, 536 nights, Oura rings vs a Polar H10 chest strap. Nightly resting heart rate with an error of about 2% and a bias of less than one beat. Study in Physiological Reports.

Fun fact: in that last study, Oura read on average 0.9 beats lower than the strap. In my test? 0.8\. A study funded by the US Air Force and me in bed with eight rings — we landed on the same number.

How a smart ring's heart rate accuracy differs between rest and activity, I covered here:

[Oura Ring 5 vs a Chest Strap: 24 Hours of Heart Rate "Accuracy"I strapped an Oura Ring 5 and a chest strap to one ordinary day — sleep, six workouts, the lot — and pulled the raw data. Here's how a smart ring actually measures your heart rate, and exactly where it goes quiet.![](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/icon/favicon-728bb791-4dc1-4145-bb04-4b7c1f86af39.ico)LordOfTheSmartRingsLORDoftheSMARTRINGS![](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/thumbnail/OURA-5-vs-chest-strap-24-hours-8ef05f0d-bb70-41c5-98af-821840fc5df1.png)](https://www.lordofthesmartrings.com/oura-ring-5-accuracy-tested-chest-strap-vs-ring/)

## 🥼 How I tested (quickly, I promise)

The referee was a **Polar H10** chest strap. It doesn't use light — it measures electrically (like an ECG) and catches every single heartbeat. Every night I paired it with my Garmin Fenix, which logged heart rate second by second, including the raw beat-to-beat (R-R) data.

I wore all the rings at the same time, for seven nights between October 9 and 17, 2026\. And I pulled the data as close to the source as possible:

- **Oura, Ultrahuman PRO and AIR** straight from their APIs (the most detailed data these companies give you) — huge brownie points to both of them for being open with our data.
- **Circular, Muse, Leep, RingConn and Amazfit Helio** from an Apple Health export — exactly the numbers each ring's app writes into Apple Health, which other apps then pull from.

![Eight smart rings on my fingers during the test, labelled](https://storage.ghost.io/c/b8/5c/b85c2e68-4736-48ae-83b9-3434527854cf/content/images/2026/10/prsteny-tep-prsteny-na-prstech.jpg)

Ring positions during the test: right hand Muse One, Circular 2, Amazfit Helio, Ultrahuman PRO; left hand RingConn Gen 3 and Oura 5 (both on the index finger), Ultrahuman AIR, Leep.

## ⏱️ How often do rings "take a snapshot" at night?

Rings only write your night heart rate into the app, API or Apple Health at certain intervals. How often the sensor actually fires up, most brands don't say. Here's what the data shows:

![How often each smart ring logs night heart rate](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/2026/10/night-hr-en_04_sampling.png)

One hour of sleep (3:00–4:00 a.m.). Every tick = one heart-rate value the ring logged.

| Ring                 | How often it logs night heart rate                       | What we know about the value             |
| -------------------- | -------------------------------------------------------- | ---------------------------------------- |
| Amazfit Helio        | every 5 min (12× per hour)                               | reading lasts about 1 minute             |
| Circular Ring 2      | irregular, every 3–5 min (13× per hour)                  | timestamp only, duration not stated      |
| Leep                 | every 5 min (11× per hour)                               | timestamp only, duration not stated      |
| Muse Ring One        | every 2 min, but with long gaps (9× per hour on average) | timestamp only, duration not stated      |
| Oura Ring 5          | every 5 min (12× per hour)                               | 5-minute value (probably an average)     |
| RingConn Gen 3       | every 10 min (6× per hour)                               | each value covers 10 minutes             |
| Ultrahuman PRO / AIR | every 6 min (10× per hour)                               | 32-second reading (per the manufacturer) |

Remember two rows in particular: Muse, which logs the most often, and RingConn, which logs the least. We'll come back to them in a minute.

## ❌ DON'T BUY: three rings that miss the mark at night

![Same night: Oura Ring 5 vs Circular Ring 2 against the chest strap](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/2026/10/night-hr-en_01_night_oura_vs_circular.png)

Night of Oct 12–13 (the Circular's worst of seven). Oura hugs the strap line. The Circular scatters dots where I definitely wasn't. Check the other rings in the interactive chart below.

Look at the chart on the right. This isn't a ring that just runs a little high. It looks like it's occasionally measuring somebody else. I'm sleeping at 45 bpm, and in between, dots pop up at 70, 80, 90.

And here's the first surprise I promised. When these rings get it right, they're actually pretty accurate — the typical error for both Leep and Circular is around 2 beats. **The problem isn't that the sensor can't measure. The problem is that the ring lets readings into your data that it should have thrown away.** Good rings recognize a bad signal and simply don't log it. These ones log it — and act like everything's fine.

**Circular Ring 2:** 28% of night readings are more than 10 beats above the strap. The nightly average came out 2.5 to 12.7 beats too high. And for October 14 and 15, it wrote a resting heart rate of 68 and 69 into Apple Health, while the strap's lowest five-minute average on those nights was 43\. (I already called it [the most controversial smart ring](https://www.lordofthesmartrings.com/circular-ring-2-unboxing-review/) when I unboxed it.)

![Circular Ring 2: typical night vs chest strap](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/2026/10/night-hr-ring_circular.png)

Typical night = the night with the median error out of seven. Black line = chest strap, dots = ring.

**Am I the one making the mistake?** I double-checked. Here's a night in my analysis (Apple Health data): 74 bpm. In the Circular app? Also 74\. The chest strap at the same moment: 45.

![The same reading in my analysis and in the Circular app: 74 bpm at 12:26 a.m., strap 45](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/2026/10/night-hr-circular_check_en.png)

Left: my analysis of the Apple Health data. Right: the Circular app. Same reading, same number — so the error isn't in the data transfer or in my calculation.

**Leep:** 19% of readings overshoot by more than 10 beats, often straight up to 85–96 bpm while I was sleeping at 45\. Nightly average +2.8 to +10.3 beats.

![Leep: typical night vs chest strap](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/2026/10/night-hr-ring_leep.png)

Typical night = the night with the median error out of seven. Black line = chest strap, dots = ring.

**Muse Ring One:** 42% of readings more than 10 beats above the strap — and on two nights, 66% and 72%. On its worst night, it claimed my heart was beating around 75 all night long. The strap said 47\. ([Muse Ring One unboxing](https://www.lordofthesmartrings.com/muse-one-ring-the-wait-is-over-unboxing-and-first-test/).) And whole runs of its readings show exactly 94 bpm, as if it got stuck on that value.

![Muse Ring One: typical night vs chest strap](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/2026/10/night-hr-ring_muse.png)

Typical night = the night with the median error out of seven. Black line = chest strap, dots = ring.

Here's the average night heart rate. If you're wondering why Oura reads lower, it's because it "misses" a lot of short episodes when heart rate rises in some sleep cycles — more in [Oura vs chest strap](https://www.lordofthesmartrings.com/oura-ring-5-accuracy-tested-chest-strap-vs-ring/).

![Average night heart rate: ring vs chest strap](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/2026/10/night-hr-en_03_average_hr.png)

Average night heart rate over 7 nights. Bar = what the ring showed, black tick = chest strap.

## ✅ BUY: five rings that nailed the night

Now for the good news. These five rings handled the night, and I trust their numbers.

**Amazfit Helio — overshoots once in a while, but doesn't wreck the night.** A few single readings fly off, but the nightly average stayed within 2.6 beats of the strap.

![Amazfit Helio: typical night vs chest strap](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/2026/10/night-hr-ring_helio.png)

Typical night = the night with the median error out of seven. Black line = chest strap, dots = ring.

[Buy Amazfit Helio Ring (Amazon)](https://amzn.to/49Z2Q2U?ref=lordofthesmartrings.com)

**Oura Ring 5 — boringly reliable.** Seven nights, not a single spike over 10 beats. Its one flaw: the nightly average is 0.9–1.2 beats lower than the strap. Every night. But it's consistent, and you can live with that, because what really matters is the change from your own baseline. (How Oura compares with Whoop and Garmin over 637 nights is in [Oura vs Whoop vs Garmin: Same Night, Opposite Advice](https://www.lordofthesmartrings.com/oura-vs-whoop-vs-garmin-637-nights/).)

![Oura Ring 5: typical night vs chest strap](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/2026/10/night-hr-ring_oura.png)

Typical night = the night with the median error out of seven. Black line = chest strap, dots = ring.

[Buy Oura Ring 5](https://lotsr.link/oura?ref=lordofthesmartrings.com)

*A note for Oura Ring 4 owners:* the previous generation measures heart rate the same way, so this verdict applies to you too. I wore both generations at the same time and compared them in [Oura 5 vs Oura 4: Parallel Test of the Measured Data](https://www.lordofthesmartrings.com/oura-5-vs-oura-4-part-ii-the-parallel-test/). No need to upgrade for heart-rate accuracy.

**RingConn Gen 3 — measures less, but honestly.** Only six values an hour, each covering ten minutes. And still not a single spike more than 10 beats up. Nightly average 1.6–2.0 beats below the strap, again rock-steady. (More in my [RingConn Gen 3 review](https://www.lordofthesmartrings.com/ringconn-gen-3-review/).)

![RingConn Gen 3: typical night vs chest strap](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/2026/10/night-hr-ring_ringconn.png)

Typical night = the night with the median error out of seven. Black line = chest strap, dots = ring.

[Buy RingConn Gen 3](https://ringconn.pxf.io/GbVYN6?ref=lordofthesmartrings.com)

**Ultrahuman Ring PRO and AIR — the reliable twins.** For both, the nightly average lands within ±1.4 beats of the strap. Now and then a single reading flies off (2–3%), but the night as a whole is spot-on. And unlike Oura, they often catch some of the short heart-rate peaks too, which gives them a more accurate average.

![Ultrahuman PRO and AIR: typical night vs chest strap](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/2026/10/night-hr-ring_ultrahuman.png)

Typical night = the night with the median error out of seven. Black line = chest strap, dots = ring.

[Buy Ultrahuman Ring PRO – 10% OFF (code FITNESATOR10)](https://www.ultrahuman.com/global/ring-pro/buy/?affiliateCode=fitnesator&ref=lordofthesmartrings.com)

[Buy Ultrahuman Ring AIR – 10% OFF (code FITNESATOR10)](https://lotsr.link/ultrahuman?ref=lordofthesmartrings.com)

Ultrahuman discount code: **FITNESATOR10** takes 10% off both the Ring PRO and the Ring AIR (applied at checkout). Current prices and offers are always on my [Ultrahuman discount code](https://www.lordofthesmartrings.com/ultrahuman-discount-code/) page.

## 🤯 Measuring more often doesn't mean measuring better

And now, surprise number two. Remember the frequency chart? Muse logs heart rate the most often — as often as every two minutes. And it finished dead last. RingConn logs only once every ten minutes — and not a single spike upwards.

Measuring more often doesn't help if the ring can't tell which readings are bad. RingConn logs one value per ten minutes, which naturally smooths out the noise. Oura and Ultrahuman seem to throw out the low-quality stretches (which is why Oura's night data sometimes has gaps). Muse, Circular and Leep keep everything. It's like taking a photo every two minutes… and keeping all the blurry ones in your album.

## 🔄 Is this the final verdict? Nope.

I want to be fair: this is the state of things as of October 2026, on the firmware these rings had at the time. **It's not a life sentence.** Firmware can change accuracy a lot — I've seen it first-hand.

So if Circular, Muse or Leep ship a fix, I'll happily put them back under the strap and update this article. Until then, the rule is simple: you're buying the ring as it is today, not as it might be someday.

## 🧠 What to take away if you already own a ring

- **Check your night heart-rate chart.** If, in the middle of the night, you see regular spikes to 70–100 bpm while everything around them sits at about 50, that's most likely a measurement error, not a nightmare. Although it might be a nightmare for whoever paid hundreds of dollars for that ring…
- **Watch the trend, not one number.** Even a good ring gets single readings wrong. That's why you look at weeks, not one morning.
- **Update your firmware.** I've seen it make the difference between "way off" and "spot-on".

## 📊 See it for yourself

Pick a night, switch on the rings you care about, and compare them with the strap:

Every ring vs the chest strap: pick a night and switch rings on

night of Oct 9–10night of Oct 10–11night of Oct 11–12night of Oct 12–13night of Oct 13–14night of Oct 14–15night of Oct 16–17 (after 4 beers) AllNone✓ Buy✗ Don't buy

HelioCircular 2LeepMuseOura 5RingConn 3UH AIRUH PRO

![Night heart rate: rings vs chest strap](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/2026/10/night-hr-en_01_night_oura_vs_circular.png)

Black line: Polar H10 chest strap (1-min average). Dots: what the ring logged. Scroll or drag to zoom. Data: Oura and Ultrahuman API, others Apple Health · LordOfTheSmartRings.com

## 🏆 So who won?

I promised you a winner. Here's the full ranking, based on how many beats each ring is off, on average, at night:

![How many beats each smart ring is off at night – ranking](https://storage.ghost.io/c/01/ca/01ca9f1d-13b0-43d5-a8fe-dac2f7d3dc2f/content/images/2026/10/night-hr-en_02_ranking.png)

The shorter the bar, the more accurate the ring. 7 nights, all rings worn at once, chest strap as the reference.

| #  | Ring                      | Average error | Readings within 3 beats of the strap | Spikes 10+ beats up | Nightly average vs strap |
| -- | ------------------------- | ------------- | ------------------------------------ | ------------------- | ------------------------ |
| 🥇 | **Oura Ring 5**           | 1.0 bpm       | 93%                                  | 0%                  | −0.9 to −1.2             |
| 🥈 | **Ultrahuman Ring PRO**   | 1.5 bpm       | 90%                                  | 2%                  | −1.0 to +1.0             |
| 🥉 | **Ultrahuman Ring AIR**   | 1.6 bpm       | 90%                                  | 3%                  | −0.3 to +1.4             |
| 4. | RingConn Gen 3 (4 nights) | 2.0 bpm       | 79%                                  | 0%                  | −2.0 to −1.6             |
| 5. | Amazfit Helio             | 3.1 bpm       | 67%                                  | 3%                  | −0.3 to +2.6             |
| 6. | Leep (6 nights)           | 7.6 bpm       | 61%                                  | 19%                 | +2.8 to +10.3            |
| 7. | Circular Ring 2           | 8.1 bpm       | 58%                                  | 28%                 | +2.5 to +12.7            |
| 8. | Muse Ring One (6 nights)  | 15.7 bpm      | 40%                                  | 42%                 | +5.7 to +28.3            |

**The winner is the Oura Ring 5.** The smallest error, the most readings within three beats of the strap, and seven nights without a single nonsense spike. Its one "sin" — reading about a beat low — happens so consistently, night after night, that you can treat it as a feature rather than a bug.

Silver and bronze go to the Ultrahuman PRO and AIR — and not by much. The Ultrahuman PRO actually has the nightly average closest to the strap of all (off by just 0.05 beats on average); it just lets the odd single reading slip through. Which makes Ultrahuman the best smart ring without a subscription.

## ⚠️ Being honest about the limits

❗

****Important: I'm rating exactly one thing here — night heart rate, measured on me, while I sleep.** Not build quality, size or comfort, battery life, sleep stages, the app, the price or the subscription.

- One person (me), seven nights, calm sleep with a heart rate around 45–50 bpm. On other hands and at higher heart rates, things could look different — although even after a night with four beers (average 58.5 bpm), the split between good and bad rings didn't change.
- I wore all the rings at the same time (positions in the photo above).
- For five of the rings, I'm rating the data their apps write into Apple Health. The app itself may show you a smoother chart.
- The results apply to firmware versions from October 2026.

#### ❓ FAQ

Which smart ring measures night heart rate most accurately?The Oura Ring 5: it's off by about 1 beat on average and had no spike over 10 beats in 7 nights. Second is the Ultrahuman PRO, third the Ultrahuman AIR — which makes Ultrahuman the best ring without a subscription.Why does my smart ring show night-time spikes to 70–100 bpm?Usually it's a measurement error, not your real heart rate. Weaker rings (Circular 2, Leep, Muse Ring One) log noisy readings they should throw away. Good rings recognize the bad signal and don't log the value.Is measuring heart rate more often more accurate?No. Muse logs heart rate the most often, as often as every 2 minutes, and finished last. RingConn logs only 6 times an hour and had no upward spike at all.

## Wrap-up

At 12:54 a.m. I was sleeping at 45 bpm. Most of the rings knew it; two of them thought I was up and walking around. Over all seven nights, five rings passed and three didn't.

Night heart rate is the foundation your ring builds sleep, HRV and your morning score on. If you're buying a ring mainly for sleep and recovery, this is the first test it has to pass.

That said, a firmware update can move accuracy a lot, so I'll happily rewrite this verdict as soon as the brands give me a reason to.

What should I put under the strap next?

*Ring links in this article are affiliate links: if you buy through them, I get a small commission and you pay the same. It has zero influence on the results — the chest strap decided the ranking.*

## VIDEO VERSION