Does this help? I am a physicist with interest in these subjects and have always been wary of breathwork because of tetany and the following studies. What do experts closer to this field make of these?
Ref. [2] is especially concerning to me in pushing in any sort of static apnea training or breathwork: "The time to complete the interference card test was positively correlated with maximal static apnea duration (r = 0.73, p < 0.05) and the number of years of breath-hold diving training (r = 0.79, p < 0.001)."
[1] "Brain Damage in Commercial Breath-Hold Divers" https://journals.plos.org/plosone/article?id=10.1371/journal...
[2] "Do elite breath-hold divers suffer from mild short-term memory impairments?" https://cdnsciencepub.com/doi/10.1139/apnm-2017-0245
Ref. [2] is especially concerning to me in pushing in any sort of static apnea training or breathwork: "The time to complete the interference card test was positively correlated with maximal static apnea duration (r = 0.73, p < 0.05) and the number of years of breath-hold diving training (r = 0.79, p < 0.001)."