Check out this video on YouTube:

Wim Hof has scientifically proven that he can control his immune system and negate the affects of temperature all by using a simple practice of breathing.

He had climbed Mt Everest on shorts and no shirt. Run a marathon in the desert without water. Broken a world record for swimming under the ice.

All this achievement from a simple breathing exercise. I’ve enclose a small sample of what he teaches but suggest you look into it for yourself.