Apple Watch now measures your heart rate every five seconds

Apple has released two new watches: the Apple Watch Series 12 and the more powerful Apple Watch Ultra 4. Both are built around a new chip called the S11, which Apple itself describes as the most powerful it has ever put in a watch.

More frequent health measurements

The big news is how often the watches now keep an eye on the body. Previously, the Apple Watch measured heart rate about every five minutes. Now it happens every five seconds, all day long. At the same time, the watches measure so-called heart rate variability, meaning how much the time between each heartbeat varies, which is used as a measure of stress and recovery. This now happens up to 24 times more often than before.

All the new measurements are gathered in a new feature called Readiness, a kind of daily form score from 0 to 10. The score is calculated by a machine learning model, meaning a computer program trained to find patterns in data about your activity, sleep and heart rate. Based on the score, you get a short recommendation such as "rest," "take it easy" or "today you can go all out."

The step counter has also been updated with new algorithms, which according to Apple make it the most accurate on the market among smartwatches.

New audio and speech features

On the audio side, new features arrive under the name Audio Intelligence. Among them is Live Rewind, where a double tap on the watch shows the last 15 seconds of speech as text, and Siri Recap, which makes a short summary of a conversation. The features run locally on the watch in an isolated, secured hardware enclave, so the audio is not stored or sent anywhere, according to Apple.

The watch runs the new software watchOS 27, where Siri, Apple's voice assistant, has become sharper with help from Apple's AI system, called Apple Intelligence. The battery still lasts about a day with normal use, and a quarter of an hour of charging gives several hours of extra power.

Price and launch in Denmark

The Apple Watch Series 12 costs from DKK 3,499, while the Ultra 4 costs from DKK 6,999. Both models can already be bought in Denmark through Apple's Danish online store, and they hit stores on September 18.

For ordinary users, the update first and foremost means that the watch can give a faster and more detailed picture of how the body is doing right now, instead of a snapshot from several hours ago. Whether the new Readiness score actually hits the mark is something independent reviewers are currently testing.

What it means for you

If you already have an Apple Watch, you'll get the new measurements automatically with an update to watchOS 27. If you want the Series 12 or Ultra 4, you can buy them in Apple's Danish online store right now. Use the Readiness score as a pointer to your daily form, but take it with a grain of salt until more people have tested how accurate it is.