At the Radboud University Nijmegen Medical Centre, professor of experimental intensive care medicine Dr. Peter Pickkers and his team have performed research on "Iceman" Wim Hof. Hof claims that he can influence his autonomic nervous system and immune response through concentration and meditation. The results obtained are remarkable, however, the investigators emphasize that so far, these results have only been obtained in a single individual. Therefore, they can not serve as scientific evidence for the hypothesis that the autonomic nervous system and the immune response can be influenced through concentration and meditation techniques. Further research with larger groups is warranted.

Research on the immune response

A well-functioning immune system protects us against viruses and bacteria. However, excessive activation of the immune system can cause tissue and organ damage. The immune system is, in part, controlled by the autonomic nervous system, a system which cannot be deliberately influenced. Professor Peter Pickkers and PhD candidate Matthijs Kox investigate the effects of the autonomic nervous system on the immune response.

Pickkers said: "We administer endotoxin, a dead cell-wall component of bacteria, to healthy volunteers. The immune system reacts as if real live bacteria have entered the body and mounts an immune response characterized by the production of inflammatory mediators and flu-like symptoms like fever, chills and headache. These experiments are completely safe and have been performed on more than 240 subjects in our centre."

Results obtained in the Iceman

Wim Hof is well known for his remarkable activities in extremely low temperatures. Hof claims that he can influence his autonomic nervous system and thereby suppress his immune response through concentration and meditation.

To investigate this, Hof was administered endotoxin while practising his concentration and meditation technique. During this experiment, various measurements were performed, including brain activity, autonomic nervous system activity and inflammatory mediators in the blood.

Pickkers said: "After endotoxin administration, the increase of the stress hormone cortisol in Hof was much more pronounced compared to other healthy volunteers. We know that this hormone is released in response to increased autonomic nervous system activity and that it suppresses the immune response. In accordance, the levels of inflammatory mediators in Hof's blood were much lower. On average, Hof's immune response was decreased by 50 percent compared to other healthy volunteers. In addition, hardly any flu-like symptoms were observed. These results are definitely remarkable. However, so far, they have only been obtained in a single individual and therefore cannot serve as scientific evidence for the hypothesis that the autonomic nervous system and the immune response can be influenced through concentration and meditation techniques. Further research is warranted in which a group of volunteers that have acquired Hof's concentration and meditation technique is compared to a group that does not master this technique."