This video describes what happens specifically in the body when you do the Wim Hof breathing technique. Breathing in a way that stimulates the fight or flight response (i.e. WHM) could act as an incredibly useful tool for dealing with inflammation or auto-immune dysfunction, and be a path to improve your health in general.
Pick up Scott Carney's book "What doesn't kill us" - ( http://amzn.to/2r2TZru ) It's an excellent account of his progress with the Wim Hof method written from a very rational point of view.
★DISCLAIMER: Though I haven't seen any information suggesting the Wim Hof method is dangerous for healthy individuals, the WHM deeply affects your physiology. So, it would be wise to consider any health issues you may have before trying it.