I've done a huge number of hours on sentry duty (unmedicated) and the the hour would either pass by in an instant and I wouldn't even realise it, or it would se

I've done a huge number of hours on sentry duty (unmedicated) and the the hour would either pass by in an instant and I wouldn't even realise it, or it would seem to drag on for hours. One thing I certainly couldn't do was pay attention to nothing happening for an hour just incase something happened.