Since I updated my watch to the full version of WatchOS9 (Have been on the beta for a while) it started overtracking fitness by a lot, like I've been active for 6x as much as I really have been. I also have barely enough battery to last half a day, when I can normally go 1,5 days.
Apple Watch SE
Hello berndvanruremonde,
We know it's important that your Apple Watch track your activity as correctly and accurately as possible. We can help.
First, make sure the device that the Apple Watch is pared to is up-to-date. If not, make a backup of the device and update the software. Here's a guide to help. How to back up your iPhone, iPad, and iPod touch - Apple Support.
If both the iPhone and Apple Watch software are up-to-date, try powering off and restarting each device. We know this sounds like a simple step, but sometimes a fresh restart can correct unusual behavior that pops up.
If the issue persists with your activity not being tracked correctly, you may want to consider calibrating your Apple Watch. This page guides you on how to calibrate your Apple Watch to improve the Workout and Activity accuracy: Calibrating your Apple Watch for improved Workout and Activity accuracy - Apple Support.
Also, be sure to note the following information:
Your personal information, such as your height, weight, gender, and age, is one of the things your Apple Watch uses to calculate how many calories you burn and more. Learn how to update your personal information.
We hope this information helps you out.
Kind regards!
WatchOS9 overtracking fitness and draining battery
