And then there is when we are doing neither. We're between breaths, or holding our breath.
Interestingly enough, there are all kind of benefits to holding our breath, including an increased lung capacity, better diaphragm control and oxygen intake, increased energy, decreased stress, etc...
Of course, when we're surrounded by water, the only water to survive is to hold our breath.
So, yes, inhale and exhale. Don't forget to breathe.
And don't forget there is a time not to.