The new Apple Watch Series 3 is coming with a new software update on September 19. WatchOS 4 will pack various improvements that would include health and wellness-related improvements.
These developments focus on furthering the new and sportier types and will surely improve experience of the users.
Make sure you manually check out the release of the 4th version of WatchOS on Sep. 19. You will have to do that if your watch does not notify you to update the WatchOS which is already present in your device.