Shutting down, have to charge it.

Hi guys!

First off, my battery health is at 88%, so its not at 60,50 or something else.

The watch is shutting down sometimes and its hard to understand why. I've noticed that sometimes its shuts off when Im riding a bicycle and its to "Shaky", maybe I dont know it thats the problem and to start it up again I need to charge it. What do you think? Im satisfied with a wild guess!