The title kinda of sums it up. Have you ever experience getting physically tired in dreams; like from running or carrying stuff?
From what I can recall, there hasn’t been one dream where I have gotten tired by doing things. I remember from one of the few LDs I’ve had, where I was carrying this one-handed sword. It was abnormal heavy, but I never actually got tired of using it while I was fighting against some random knight.
I think only if you expect or fear to get tired you can be.
I’d say the same.
Generally, i don’t get tired of anything, unless i think about that i -should- be tired doing that IRL, which thankfully happens very rarely.
I can’t remember an instance that involves waterbreathing, my dreams don’t typically stray there. I expect it’s the same, you only need to breath if you remember that you do.
Yeah it’s all in the mind I say. Last night I did about an hour of not-stop, high-intensity, videogame-style martial combat without feeling anything like exhaustion or tiredness, but I bet in a LD with good control you could get out of breath within seconds by the mere thought of it.
Yep, all about the mind here 
in several dreams I have had I could run as long as I liked without getting tired while the mere thought of stamina makes you tired 
yup mind over matter 