"if you don’t end your activity… "
Yes but I did end it and was in trouble.
All your answers make no sense and don’t address the point:
Who is the genius in Suunto who decided you need to download tracks to a phone and then upload them back in order to be able to follow them on the watch?
The data is already in the watch, let me use it, please!
And besides, the battery of my watch outlasts the one of my phone, so the situation was not unexpectable (some of you who answered would probably come up with this great solution: make the battery of the watch last less