By Ed Hardy • 8:12 am, May 1, 2022

Apple developers are trying to enable the upcoming Apple Watch Series 8 to sense the wearer’s body temperature, according to a trusted analyst. But it’s not a done deal. Cupertino also hoped to make sensing body temp part of Series 7 but couldn’t work out the bugs.

This is just one of the health-related sensors that are proving to be a challenge for the Apple Watch team.

There’s no more basic health indicator than temperature. That’s because the body warms itself up in response to infection. A body temperature sensor in an Apple Watch would be able to alert the user that they’re ill – and possibly contagious – before they notice themselves.

Apple is trying. “I believe Apple Watch 8 in 2H22 could take body temperature,” Ming-Chi Kuo an analyst with TF International Securities, said Sunday via Twitter.

But it’s not easy. “Apple canceled body temperature measurement for Apple Watch 7 because the algorithm failed to qualify before entering EVT stage last year,” Kuo noted. And it’ll only become part of Series 8 “if the algorithm can meet Apple’s high requirements before mass production.”

Taking body temperature is a challenge for a wrist computer. A standard thermometer is placed under the tongue to get the body’s core temperature. That’s not an option for a watch. It has to use skin temperature, and “skin temperature quickly varies depending on outside environments,” said Kuo.

The answer is an algorithm that can use skin temp to infer the core temp. As noted, Apple developers have so far been unable to make one that’s sufficiently accurate.

A previous report indicated Apple’s next wearable might be able to detect elevated body temperature without giving an exact number.

Apple isn’t the only company struggling with this task. Kuo predicts the Galaxy Watch 5 will lack a body temp sensor because Samsung can’t get it to work right.

(2/3) The challenge in implementing precise body temperature measurement is that skin temperature quickly varies depending on outside environments. A smartwatch can't support core temperature measurement in terms of hardware, so it needs an excellent algorithm to work together.

Heath sensors are a significant part of the Apple Watch’s feature set. Series 7 looks for irregular heart rhythms and dangerously low heart rates. It can also measure blood oxygen levels.

But adding new ones to Series 8 is causing Apple headaches. In addition to the body temperature problem, the company has reportedly had to push back the debut of blood pressure and blood glucose monitoring.

Still, Apple reportedly plans to add new women’s health features plus new sleep-, fitness- and medication-management options in the ‌Health app for Apple Watch and iPhone in 2022.