Wear OS is getting a new update. Known as "H", it adds a new battery-saving mode to Android-powered watches. The new update also overhauls how a watch reboots or shuts down, as well as how it resumes apps and handles the switch to sleep mode.
https://www.notebookcheck.net/New-Wear-OS-update-brings-Battery-Saver-Mode-and-more.362906.0.html