Is it essential to breathe during a golf swing and a snooker shot? if yes, what is the best sequence to learn?

I am a good golfer and good snooker player but I have always held my breath during a golf swing and a snooker shot probably believing this was preventing unwanted movement during the process and nothing atall to do with tension. However during golf practice and several practice swings I am aware I am uncomfortable and believe I must have this concept wrong. I also believe I may be restricting some cue-action.