tetany

Just to clarify, you aren't talking about tetany, but say, cheek muscles or perhaps the forehead?

I started hyperventilating, breathed in some water, and started to get tetany which of course made everything worse.

I've done breathwork for years, and at some point the tetany simply stopped happening and hasn't returned.

In a medical setting, where I am more familiar with it, tetany is never good.

That's tetany, and it's a very clear sign of respiratory alkalosis.

I am a physicist with interest in these subjects and have always been wary of breathwork because of tetany and the following studies.

You can do alkalizing breath exercises without inducing tetany.

The tingles and muscle cramps (tetany) are a normal byproduct (basically your neurons on your smallest muscles and under your skin get more excitable due to a molecular rube goldber machine set off by lower CO2 balance in your blood).

So the tetany in breathwork is generally caused by the decreased CO2 concentration causing respiratory alkalosis (ie blood gets more alkaline and has a ph balance of > 7.5), which in turn causes the protein albumin to bind more strongly to calcium and not release it as it's supposed to, and calcium is an important regulator in voltage gated ion channels in neurons.

Alkalosis often leads to muscle spasm, tetany, anxiety, and panic (Fried, 1987; Lowry, 1967; Nakamura, 1981; Rhinewine & Williams, 2007), with Nakamura noting that when the pH exceeds 7.60, hyperventilation tetany takes place.

Not to mention the hypercapnia induced tetany is very uncomfortable and seems a clear signal from the body that "this isn't good!".

I've experienced quite severe tetany from controlled and deliberate hyperventilation ("bioenergetic breathing"/"round breathing"/"breath of fire").

I mentioned the tetany exercise because you were asking me to hook up a pH meter to my bloodstream to "objectively prove" that voluntarily changing respiration can lead to significant pH shifts in the blood.

I understand the tingling of the fingers to be caused by a reduction of calcium ionization: "Low levels of carbon dioxide cause tetany by altering the albumin binding of calcium such that the ionized (physiologically influencing) fraction of calcium is reduced; one common reason for low carbon dioxide levels is hyperventilation."

Tangential but to anyone who is tired and anxious I recommend also checking for Tetany[0].