I don't know a lot about the mechanics of instruments, but on the basis of my arguments for singing, I would think that playing a woodwind or reed or brass instrument would have very similar effects because I'm told these also require (perhaps even more so) deep breathing and very controlled, pressured blowing out over a sustained phrase, repeatedly. Humming and whistling would seem to share some components but maybe more weakly (depending on how you do them I guess).

It's always intrigued me that some musical instruments might owe their emotional power in part to mimicking acoustic features of the human voice that correspond to emotional signals. Whether or not that's true, certainly musical melodies have the characteristics of prosody (modulation of pitch and timing). So the arguments about the benefits of auditory feedback or simply listening to singing would apply even to non-breath-powered instruments.

I've got to find another word than "soothing" for this vagal effect, however, because all this is applicable to intense, exciting, passionate music too, it's not just about lullabies and lilting ballads. Maybe "restorative", "replenishing", "resourcing"?

I'm sure there's another story to be told about how music organizes sequences to unfold in the brain, and how powerful this is for retrieving memory. Even people who can't recite a single couplet of poetry can sing (often to their own surprise) dozens of songs from memory once you get them started.

There seems to be a growing movement to bring music into hospitals to aid recovery, whether or not there are hard data to support it, I'm all for it. Personally I sang ballads and played old country songs on the Autoharp for hours every day during my partner's grueling in-patient cancer drug infusions. It seemed to help both him and me endure those miserable and scary times. Which reminds me of another useful thing about songs - words and narratives distract the verbal mind, and save us from perseverating and worrying thoughts, which helps break a cycle.

P.