In 2014, a study published in PNAS by Kox et al. at Radboud University enrolled 24 subjects, half trained in the Wim Hof Method combining cold exposure, meditation, and a specific cyclic hyperventilation breathing technique, and infected all of them with a bacterial endotoxin to provoke a controlled immune response. The trained group showed significantly lower levels of inflammatory cytokines, fewer flu-like symptoms, and higher circulating adrenaline compared to untrained controls. This was the first peer-reviewed demonstration that the autonomic immune response could be voluntarily influenced through a learned technique.
The Mechanism: Adrenaline and Cytokine Suppression
The breathwork component of the Wim Hof Method involves cyclic hyperventilation, producing temporary alkalosis and elevated adrenaline. High adrenaline suppresses the pro-inflammatory cytokine response, particularly tumour necrosis factor alpha, interleukin 6, and interleukin 8. In the 2014 trial, trained subjects showed adrenaline levels comparable to those seen in a first bungee jump. This voluntary adrenaline surge appears to be the primary mechanism by which the technique modulates the innate immune response.
What This Does and Does Not Mean
The Kox trial demonstrates voluntary influence over an acute inflammatory response. What it does not demonstrate is long-term immune enhancement or protection against infections beyond the specific endotoxin model. The hyperventilation breathwork involved is physiologically demanding and not appropriate as a daily practice for most adults. It should not be practised near water, when driving, or without guidance. However, the finding that the autonomic nervous system and innate immune response are not as involuntary as previously assumed has significant implications for breathwork research more broadly.
Slower Breathwork and Chronic Immune Regulation
For everyday immune support, slower parasympathetic-activating breathwork is more appropriate and has better safety than cyclic hyperventilation. Chronic sympathetic dominance, the stressed state of most modern adults, suppresses adaptive immune function through elevated cortisol and adrenaline. Regular slow breathing practice reduces baseline cortisol, decreases circulating inflammatory markers, and may improve mucosal immunity through its effects on vagal tone, which is known to modulate gut-associated lymphoid tissue.
- Daily slow breathing at six breaths per minute for 15 minutes reduces baseline cortisol over four to eight weeks
- Do not practise cyclic hyperventilation without proper instruction: it carries risks including syncope
- Cold exposure combined with breathwork increases the immune-modulating effects seen in the Kox trial
- Adequate sleep and stress management remain the most evidence-based immune support strategies
- Nasal breathing during exercise maintains mucosal immune defences in the upper respiratory tract
Sources
- Kox, M., et al. (2014). Voluntary activation of the sympathetic nervous system and attenuation of the innate immune response in humans. Proceedings of the National Academy of Sciences, 111(20), 7379-7384.
- Zaccaro, A., et al. (2018). How breath-control can change your life. Frontiers in Human Neuroscience, 12, 353.