Same thing happens to me. Especially when I’m writing or concentrating on something really hard. When I pause, I’ll sigh, and my husband immediately wants to know what’s wrong. We have this exchange at least three times a day.
Me: sigh
Him: What’s wrong?
Me: Nothing. I’m just breathing.
And on it goes. sigh
Count me in as one of the unconscious sighers, or whatever (I sigh all the time and don’t realize I do it). I suppose I don’t breathe as well as I should.
A bit of both? While leaving the office yesterday, I heard myself giving a long sigh - then turned a corner, and saw my boss - oops.
I certainly didn’t mean to sigh, it just happened. I definitely didn’t mean to be heard. But my subconcious can be overdramatic.