How long can you delay "ready" action

In real life, adrenaline helps but fatigue. In RPG, in theory, players may say they are alert for hours...

The only "fatigue" rule in DD is the barb's after-rage fatigue. Anyone has idea how long you may remain "alert" and "with weapon ready" ? Fortitude roll (endurance applies!) vs ?

10 after 10 first minutes, +1 each extra 10 minutes ? Seems good ? There is an official rule ?

It really depends on what you mean by "alert". Standing behind a door with the waraxe above your head ready to slash down on the first thing through said door? Muscles clenched and slow breathing and all that? Not long and I would personally give a negative to the dolt telling me that is what he is doing. If you mean weapon out scanning an area alert to the goings on of the area that is taken care of by listen and spot checks and the alertness feat. Failure indicts you were napping while the whatever came close enough to give you such a whack

You can ready as long as the game is timed in rounds. When the action stops, you stop readying, and would have to roll initiative as normal when a new encounter starts.

Geoff.