Which health wearable should you buy?

Best sleep tracker

A sleep tracker is only as good as your willingness to wear it in bed, which is why the rings win on comfort: the Oura Ring 5 starts at 2 g and the Ultrahuman Ring PRO at 3.3 g, against about 26.5 g for a Whoop band and 30.3 g for the smallest Apple Watch. Battery matters just as much, because a device you charge at night is a device that misses nights. Apple Watch Series 11 claims up to 24 hours of normal use; every other device here claims a week or more, and the Withings ScanWatch 2 claims 35 days.

On what they actually record overnight, four stand out. Oura measures SpO2 while you sleep, needs a sleep period longer than three hours, and reports Average Blood Oxygen for the night. Withings runs 24/7 temperature tracking alongside overnight HRV and a Breathing Quality Index. Garmin's CIRQA and Venu 4 let you set Pulse Ox to “During Sleep” for continuous overnight readings. Samsung's Galaxy Ring measures heart rate, blood oxygen and skin temperature while you sleep. Whoop reports blood oxygen, skin temperature and respiratory rate too — but only on the Peak and Life plans, since Whoop states WHOOP One members do not get Health Monitor.

Best wearable for HRV

If HRV is the number you care about, the question is not who measures it — nearly everything here does — but *when*. Oura states it measures HRV only during sleep, takes five-minute samples through the night, and shows the mean of those samples. Whoop tracks HRV passively through sleep and takes the reading that drives Recovery during slow-wave sleep. Garmin measures the time between heartbeats while you sleep and needs seven nights before it shows a seven-day average, and about three weeks before it compares that to your baseline. Polar takes HRV nightly for Nightly Recharge, on both the Loop and the Vantage V3.

Apple Watch is the outlier: Apple's own heart-rate paper describes a background algorithm that watches heart rate through the day and reports a reading roughly every five minutes whenever you are still, published as SDNN. That is a different statistic sampled at a different time, so an Apple HRV number is not comparable to an overnight one. Samsung is the gap — HRV is not named on the Galaxy Ring product page, its buy page, or either of its support articles.

For getting that HRV out of the vendor's app and into your own analysis, Polar and Withings are the easiest: both run public APIs you can register for directly. Oura's API is open to any account holder but needs an active Membership on Gen3 rings and newer. What counts as a good HRV is a separate question — the short answer is that it only means anything against your own baseline.

Oura vs Whoop

The clearest split is commercial, not technical. Oura sells you a ring — €429 for Silver or Black on its EU store — and then charges €69.99 a year for Membership on Gen3 rings and newer, which comes to €568.98 over two years. Whoop does not sell a device separately at all: WHOOP One is €199 a year and WHOOP Peak €264 a year on the EU storefront, each including a WHOOP 5.0, so two years costs €398 or €528 with the hardware bundled in. Technically, the ring is 2 g and the band about 26.5 g; neither has GPS. If you want ECG you need WHOOP MG on the €399-a-year Life membership, since Whoop states outright that WHOOP 5.0 does not include it. See also our longer read on why the recovery scores disagree.

Smart ring vs watch

None of the three rings here — Oura Ring 5, Samsung Galaxy Ring, Ultrahuman Ring PRO — has GPS or an ECG. All three claim a week or more of battery and weigh single-digit grams. The watches invert that: Apple Watch Series 11 adds ECG, fall detection, built-in GPS and sleep apnea notifications, but claims up to 24 hours of normal use, which means charging around your sleep window. The Withings ScanWatch 2 is the odd one out — a hybrid watch with ECG and 24/7 temperature tracking that claims 35 days.

Wearables without a subscription

Garmin is the loudest on this. The CIRQA Smart Band is sold under the tagline “Track all day. Look later. No subscription required.”, and Garmin states its data syncs to the Garmin Connect app at no additional cost, with Connect+ ($6.99 per month or $69.99 per year) strictly optional. Polar puts it in writing too: “No monthly fees. No locked features. Full access to every feature from day one.” At the other extreme, Whoop has no non-subscription path, and Oura's Membership is what unlocks API access on Gen3 rings and newer — so if you plan to use your own data outside Oura's app, the Membership is not optional.

Definitions

HRV (heart rate variability) is the variation in the time between consecutive heartbeats, measured in milliseconds. It is not a fitness score; it is a rough readout of autonomic nervous system balance, and it is only meaningful against your own baseline. Different vendors compute it differently — Apple publishes SDNN, the standard deviation between normal beats — and different vendors sample it at different times, which is why two devices worn on the same night can disagree.

A readiness or recovery score is a vendor's proprietary blend of overnight signals — typically HRV, resting heart rate, sleep and recent activity — compressed to a single number, usually 0–100. There is no industry definition and no shared scale. SpO2 is blood oxygen saturation, estimated optically. Skin temperature is usually reported as a deviation from your own recent nights rather than an absolute reading. Connected GPS means the device has no GPS chip and borrows your phone's.

Where Vitra fits, honestly

Vitra is a desktop app that reads your ring's data and explains it. The last row of the table above has exactly three states. Yes — Oura, read through the public Oura API, and that is the whole supported list today. Being worked on — Polar, whose support is written but still sits behind a switch that is off; plus Ultrahuman and Withings, both on the build list because each runs an API a third party can actually reach. None of the three is usable yet, and none is on offer. No — everything else, with the real reason spelled out in the cell rather than a vague “coming soon”. Nothing sits in “being worked on” that is not genuinely on the build list.

Two of these devices cannot be supported by a desktop app at all, and it is worth saying why rather than leaving it vague. Apple Health hands data to apps running on the user's own iPhone or Apple Watch; Apple states there is no route by which Apple itself gets access, and there is no server-side API for a desktop app to call. Samsung Health is read through an Android on-device SDK, with no public cloud API. Google's cloud route, the Google Health API, gates every scope behind a privacy and security review. Those are checkable facts, not excuses — but they are also the reason a Mac or Windows app will not be reading your Apple Watch any time soon.

The unflattering part: because Vitra reads Oura through the Oura API, and Oura requires an active Membership for API access on Gen3 rings and newer, Vitra cannot remove that recurring cost for you. It removes its own — Vitra is a one-time purchase — but the Membership underneath is Oura's, not ours.

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