After hearing Jack Kruse speak on TedX, I immediately became interested in his example of Wim Hof. Climbing Everest without a shirt? Really? Pretty crazy. Here is his video on TedX. A scientist comes on and talks about how he thinks Wim is able to do such things.
Here is the article in Science Daily about Wim and his control of the autonomic nervous system. Research on ICEMAN.
Remember we may not have the ability of Iceman, but you to can control the autonomic nervous system with proper diaphragmatic breathing. This too is powerful!