Apple Watch Series 12 Heart Sensor Holds Up in an Early Outside Test
Apple's new watch checks your heart rate every five seconds. A chest strap test found it accurate, but not a big leap over last year.
Apple Watch Series 12 reached stores on September 18, starting at $399. Its biggest change is a redesigned set of heart sensors, and the first outside test says they work well.
What Is New
Apple calls the new sensor setup the Health Sensing System. The company says the watch now checks your heart rate every five seconds through the day. It also says heart rate variability, a sign of stress and recovery, can be measured up to 24 times more often than before.
A new Readiness Score rates you from 0 to 10 each day. It then suggests one of four plans, from Recover to Go For It.
The watch comes in 42mm and 46mm sizes and runs watchOS 27. Apple rates the battery at up to 24 hours.
The Outside Test
Reviewer Rob ter Horst, known online as The Quantified Scientist, tested the watch against a Polar H10 chest strap. Chest straps are the usual yardstick for heart rate accuracy.
During indoor cycling, the two were almost identical. While running and lifting weights, the match was also very close. In his tests, last year's Series 11 did slightly better on runs, and overall the two watches landed in about the same place.
Apple's own accuracy claim comes from a study of more than 1,000 people.
Should You Upgrade?
If you already own a Series 11, heart rate accuracy alone is not a strong reason to buy. If your watch is a few years older, the more frequent readings may make your health trends more useful. Either way, give the Readiness Score a couple of weeks to learn your patterns.
Questions Readers Ask
What is the Readiness Score?
It is a new daily score from 0 to 10. The watch uses it to suggest whether to rest, take it easy or go hard that day.
How long does the battery last?
Apple rates it for up to 24 hours of normal use. It says 15 minutes of charging gives up to 12 hours.
Where This Came From
We confirmed the facts in this story against these reports. The words above are our own.
