Has anyone experimented with pre-dive vagal maneuvers? The mammalian dive response is itself a vagal maneuver, but there are others as well. Paramedics will use a vagal maneuver as a first line treatment to lower a SVT (super ventricular tachycardia; aka high heart rate without reason) in their patients, before administering any medication. The way they do it is to have the patient hold their breath and "bear down" as if they're trying to poop, for 15-30 seconds or more. Once they release and exhale, the heart rate will drop to a normal rhythm, 20-40% of the time, mostly depending on how effectively it's communicated and performed. Meaning, if you do it right, it works.

Now, I've developed my own version, that I've been doing since I was a kid. I used it to get rid of hiccups. It works the same as the above one, with a couple modifications. Kind of difficult to explain in words, but not that hard to teach. What I've noticed, in myself and in my students that have tried it, is that you do the maneuver, and then your heart rate shoots up, but then drops off a cliff. Average response is fairly consistently getting the heart rate to go down 10-20 BPM from the pre-maneuver rate.

It also works if you elevate your heart rate first with exercise.

My most intense reaction was after I did a bunch of pushups, my BPM was around 110. I did the maneuver, and then it shot up above 130, then quickly dropped to around 80, and then more slowly went down into the 60's, which I further dropped by deconcentrating and belly breathing into the 50's. All in the span of less than a minute.

At any rate, it has a near 100% success rate in resolving hiccups, because it activates both the vagal and phrenic nerves, causing a quick reset of your parasympathetic nervous system, and thus your normal diaphragmatic breathing rhythm.

I'm also wondering how this connects with some yoga practices. Essentially, you hold your breath, perform the 3 locks, swallow, and exhale.

Does anyone else have any experience or insight with this? I haven't been able to find any dangers or counter indications for this. It seems to be a safe, effective, and easy way of quickly lowering your heart rate, which you can then lower further with other methods. Like surfing a wave of relaxation. Let me know your thoughts.