Guide · Wearables
Both track heart rate, sleep and activity. Both can trigger an SOS. The difference doesn't come down to the feature list, but to where you'll actually end up wearing the device. And to what you want to do with it.
Want to see several readings, receive messages and press a button in an emergency? Then go for a smartwatch. Only want to track sleep and trends without anyone noticing the device? Then go for a smart ring.
Many people now wear a device on their wrist. Far fewer wear a ring. That's not down to the technology – smart rings have become surprisingly good over the past two or three years – but to a simple everyday question. Where do you want to look when you want to know your heart rate? At a display, or at an app on your phone?
That's the heart of the comparison. We'll show you the real differences, not the marketing version.
What each device can really do
Smartwatches: the display is the advantage
A health watch such as the Kardena CARE Pro 5 measures heart rate, blood oxygen, sleep, heart rate variability and skin temperature, and can record a one-minute ECG on request. A ring can't do that – not because of its sensors, but because an ECG needs two points of contact on opposite sides of the body. Watch on your left wrist, fingers of your right hand on the metal edge, done.
The second real advantage is the display. You see the reading instantly. With a ring, you have to check your phone.
The trade-off: a ring won't bother you at night, but a watch will. Light sleepers notice the difference.
Smart rings: lighter, more discreet, fewer distractions
A ring weighs between three and six grams. After two days, you no longer notice it. It looks like jewellery, not technology. That's why many people wear one round the clock – at the office and at appointments too. With a watch, that's often not the case.
And because a ring has no display, its battery lasts considerably longer. Five to seven days is standard, sometimes more. Watches with an AMOLED display manage three to seven days with typical use, depending on the model and brightness.
The downside: in everyday use, you can't see a single reading on the ring itself. Everything ends up in the app. That's enough for tracking trends. It's not enough in the moment.
The honest comparison
| Criterion | Smartwatch | Smart ring |
|---|---|---|
| Heart rate, SpO₂, sleep | Both accurate | Both accurate |
| ECG | Yes (on models such as the CARE Pro 5 and Pro 6) | No |
| SOS emergency call | Directly on the wrist, at the press of a button | Rare, and usually only via smartphone |
| Notifications | Visible on the display | Via the app only |
| Battery life | Typically 3–7 days | Typically 5–7 days |
| Comfort at night | Noticeable, can be disruptive | Barely noticeable |
| Visibility | Clearly recognisable | Looks like jewellery |
| Price range | Usually €100–350 | Usually €150–350 |
The price surprises some people: good rings tend not to be cheaper than watches. Miniaturisation comes at a cost.
Which device is really worth it – and for whom
Choose a smartwatch if ...
- you need an SOS button on your wrist (for elderly relatives, for example)
- an ECG or blood pressure estimates matter to you
- you want to read distance, pace or heart rate at a glance while exercising
- you want to see messages without getting your phone out
The CARE Pro 6 is particularly beginner-friendly: it starts up in German, the app is optional and a printed manual is included. Often the right choice for people aged 60+.
CARE Pro 6
SOS to up to 5 contacts, ECG, ~7-day battery, German default settings. Classic (round) or Modern (square).
View product →CARE Pro 5
ECG, AI micro-check, HRV analysis, Bluetooth calling, data sharing with up to 3 trusted contacts.
View product →Choose a smart ring if ...
- you're looking for a wearable that won't disturb you at night
- trends over several weeks matter more to you than individual readings on your wrist
- you don't want a visible device, whether for work or personal reasons
- you look at your smartphone a lot anyway and don't see using the app as a detour
Kardena stocks several models in its Smart rings range.
A special case: the health band
Between the watch and the ring, there's a third category that's often overlooked: a simple fitness or health band with no display. The Kardena CARE Vital 2 is one such device. It measures heart rate, SpO₂ and sleep in the background, has an SOS function triggered by pressing the button three times, and sits as discreetly on the wrist as a piece of jewellery. For people who don't want to wear a watch but still want an emergency call close at hand, it's often a better answer than a ring.
What many people overlook when comparing
Measurement accuracy isn't a yes-or-no question. Both form factors measure heart rate using photoplethysmography – in other words, light sensors against the skin. At rest, both watch and ring come close to a chest strap. During fast movement – strength training, intervals – any optical measurement becomes less accurate. That applies to both.
SOS in everyday life isn't theoretical. If someone falls and needs to call for help, it has to work within a few seconds. A watch with a button on its edge has the advantage here. Rings often have no physical button. If you specifically want the device as a safety measure for yourself or a relative, settle this question before any other.
The ring's battery advantage disappears with frequent measurements. If the app is set to 'SpO₂ every 30 minutes', even a ring's battery life drops to three or four days. You'll rarely find that on a spec sheet.
A short answer to the original question
If safety comes first – SOS, fall detection, ECG – a smartwatch is the more practical choice. If discretion and sleep analysis matter most and you don't mind checking your phone, a ring is a real pleasure to use. If you're somewhere between these two worlds and simply want an understated everyday device, take a look at the CARE Vital 2. It often suits people better than they expect.
All Kardena products come with a 24-month manufacturer's warranty on the device and 6 months on the battery, plus 30-day returns. If you still can't decide, you can get advice via our contact page or by phone from Anna on +49 30 42434749.