That's in response to cold. He has also been tested for effects on immune response: "It was shown that this individual was able to voluntarily activate the sym

That's in response to cold. He has also been tested for effects on immune response: "It was shown that this individual was able to voluntarily activate the sympathetic nervous system through a self-developed method involving meditation, exposure to cold, and breathing techniques. This resulted in increased catecholamine and cortisol release and a remarkably mild innate immune response during experimental endotoxemia compared with more than 100 subjects who previously underwent experimental endotoxemia." https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4034215/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4034215/ Perhaps it is bunk science? I'm not qualified to say. I personally did find the methods have been helpful.