We already know from previous studies that Wim Hof Method practice can bring down inflammation, and as such help manage a wide range of health conditions.
What the researchers did to come to these findings is have a bunch of folks undergo Wim Hof Method training, and then hook them up to various machines to gauge how they responded to various types and levels of pain. Meanwhile another group of people who received no training went through the same tests for comparison.
As it turns out, people who had undergone the breathing method experienced a decrease in pain induced by an electrical stimulus. Moreover, the groups that received either cold exposure training or both breathing and cold exposure, perceived less pain after having their hands submerged in water for several minutes.
It remains uncertain what exact mechanism affords this protective benefit, but it may involve pathways that are generally attributed to exercise-induced hypoalgesia— activation of the endogenous opioid system and the autonomic nervous system.
Whatever it is that's happening biochemically, these findings are incredibly exciting, as it strengthens the case for Wim Hof Method practice to be included in treatment programs for patients with inflammatory conditions.
Please bear in mind that this study was conducted on males only, who were all in good health.