Singers use extended humming to relax and access deeper vocal frequencies, which involves mechanical activation of vagal pathways that drive a parasympathetic response.

“So, it turns out that the stuff they say at retreats and yoga classes, is mechanistically supported.”

“this is the way that singers often will start to relax in order to get into some of the deeper frequency notes that they need to hit with their voice. As you've probably observed, high notes sort of bring people up into their head and up, even if they're using their diaphragm, higher and higher and higher, whereas lower frequency sounds deeper and deeper. And it's just mechanical activation of the particular branches of the vagus that are able to drive this parasympathetic response.”

“And it's a long, slow exhale. So, this is the third part. There's also a collateral activation, which is just neuroscience-speak for activation of that deceleration pathway. When you do this humming at the back of your throat, and down into your chest, and into your belly, you're also getting the same effect that you get with an exhale, which is to slow the heart rate way, way down.”

“if you want to try and really deep relax, this extended humming that you're trying to move down further and further from, say, your lips to the back of your throat, to deeper in your throat near your Adam's apple, to your chest region, even into your abdomen, and your diaphragm, you'll notice that it really, really calms you down.”