Wim Hof (“the iceman”), developed the Wim Hof Method, where people plunge themselves into ice baths or deliberately hyperventilate and then hold their breath. A new study found that it may reduce inflammation in people as it increases adrenaline levels, which decreases pro-inflammatory cytokines.
Source: journals.plos.org
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0286933