Key difference here is that freediving is apnea-induced hypoxia, whereas breathwork is literally the opposite: hyperventilation-induced hyperoxia. So while int

Key difference here is that freediving is apnea-induced hypoxia, whereas breathwork is literally the opposite: hyperventilation-induced hyperoxia. So while interesting as a study, I don't think it offers any insight into the kind of breathwork described in the nature study.