It's cool to know that our ancient instinct to sing to crying babies has the ability slow their heart rate and help them feel calm. I like the, "shh shh shhhh..." method too.

I spent A LOT of time bouncing, rocking and shhhing my baby girl when she was tiny. It did help her. But it also slowed my heart rate, chilled out my tense shoulders and quieted my racing frustrations. I think it was all the exhaling.