Ice or cold water reg preperation

[ScubaDo]

I was in 33 degree water last weekend and had my reg freeflow after 15min.  I surfaced and shut my air off for a couple minutes and retried.  Once it was working again I went back down.  This time instead of touring around the lake, I took it real slow around the weedbeds watching the fish and breathing real slow, I didn't have anymore problems.