New firmware update aims to fix CIRCUL Ring’s rough start

CIRCUL Ring is about to get a new firmware update that touches on everything from sleep tracking to step counting. It’s a big patch that seems aimed at fixing some of the biggest early complaints.

The smart ring, launched via an Indiegogo campaign in 2024, promised a broad range of health metrics in a compact design. But early impressions have been underwhelming. Users have noted issues with comfort, battery life, unreliable sleep tracking, and a finicky charging cradle. The app also felt half-baked, lacking the polish and depth needed to make sense of all the data.

This firmware update is the company’s first major attempt to turn things around.

What’s new?

One of the most important additions is a new sleep recovery index based on RMSSD, a heart rate variability measure tied to parasympathetic nervous activity. This is being used to estimate how well your body recovers overnight, factoring in heart rate, blood oxygen, and sleep stages. It’s an individualized metric that will get more accurate the more you wear the device. The app will also start displaying RMSSD and recovery trends, helping users track changes over time.

Sleep apnea detection has been tweaked to align with medical standards. Instead of flagging a 3% drop in blood oxygen as an event, the threshold has been raised to 4%, which brings it in line with CMS recommendations. That should mean fewer false positives and reports that are easier for doctors to interpret. CIRCUL says your original data remains unchanged—only the way events are tallied is different.

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Step counting has also been fine-tuned. Previous builds had issues with undercounting or inconsistent readings, and this update is supposed to improve that. Calorie estimates are being reworked too, which should help users who rely on the ring to gauge their activity levels more precisely. The sleep report section has seen upgrades as well, with better visibility into heart rate, temperature, HRV, and SpO2 fluctuations during the night.

Another change comes to daily heart rate tracking. The algorithm has been refined to deliver more accurate readings throughout the day. At least, that’s the promise.

Our takeaway

All in all, this sounds like a comprehensive update package. Whether it helps to iron out most of the issues, remains to be seen.

To the company’s credit, they’re being transparent about their roadmap. It seems blood pressure readings are in open beta, and they’re working on better stress and energy tracking. We are yet to see a smart ring that can track blood pressure with decent accuracy.

There’s also an AFib detection feature on the horizon, though it’s only in early testing for now. Behind the scenes, CIRCUL claims to have resolved some hardware issues like water resistance and general reliability, at least in newer production batches.

There’s a lot riding on these updates. The early adopter feedback has not been great, and while the ring does offer a fairly rich set of sensors, it’s only as useful as the data interpretation. Right now, the software still lags behind more mature ecosystems. The hardware also needs refinement, especially in comfort and charging consistency.

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