What action is it to start holding your breath?

[Eideann]

The subject basically says it, I can't find anything to explain how to start holding your breath and was wondering what action it would be.

[kyrt-ryder]

I would bet money it's a non action Eideann. You simply choose to stop breathing and the 'holding your breath' clock starts ticking.

[Sekret_One]

A free action. Maybe a dc 15 reflex save to do it ... reflexively?