We can learn to consciously control our immune system – that's the surprising finding from research based on the techniques of the "iceman" Wim Hof, famous for his ability to withstand cold for long periods. The research team, from Radboud University Medical Centre in Nijmegen, the Netherlands, hopes that Hof's techniques might one day be used to treat autoimmune diseases such as rheumatoid arthritis. For now, the team is trying to establish which of the three components of Hof's technique are responsible for the profound suppression of the immune system that they observed.
How Hof does it
Meditation
Specifically, third-eye meditation, where you still your thoughts through visualising a third eye on your forehead. Find out more about the science of meditation in "Mind gym: Putting meditation to the test".
Cold exposure
You might not want to try this yourself, but Hof's training regime involves swimming in near-freezing water, climbing mountains in just shorts and lying bare-chested in snow for 20 minutes.
Breathing exercises
One of these involves hyperventilating for 30 breaths, then exhaling and holding the breath for up to 2 or even 3 minutes, followed by a deep inhalation of breath that is held for 10 seconds. Hof's second breathing exercise consists of deep inhalations and exhalations with breath-holding for 10 seconds, while tightening all body muscles.
