The rhythm of his own breathing accelerated with each step.

The room was silent except for the slow, even rhythm of her breathing.

I tried to control the erratic rhythm of my breathing.

There was a slight catch in the rhythm of his breathing, but he didn't move.

Could tell in the rapid, irregular rhythm of his breathing.

After a moment, once the even rhythm of his breathing has resumed, they begin their debate in earnest.

He grew to know the rhythm of her breathing.

For a moment Jamie feared she might be dead, but then he saw the slow rhythm of her breathing.

They closed completely and she could tell by the rhythm of his breathing he'd fallen fast asleep.

Not so much as a stutter in the rapid rhythm of his breathing.