Hi @Ze11han ,
This channel explains the idea very clearly. In the video, the example is triggered when the character takes damage, but you can easily adapt the variables so the effect is driven by fatigue instead
Also In other videos, the channel also shows how to set up a health system and goes into additional features that could be useful
I’m not sure if this is exactly what you’re looking for, but this video shows how to create a stamina system. It could be a useful reference for building the fatigue system you want.