Does the Wim Hof Method have a beneficial impact on physiological and psychological outcomes in healthy and non-healthy participants? A systematic review

Abstract Introduction: Wim Hof, also known as the iceman, developed a method called Wim Hof Method which he claims to have several benefits on physical and mental health. The aim of this systematic review is to identify and synthesise the results of the studies conducted on Wim Hof Method on physiological and psychological health-related outcomes. Materials and Methods: Medline and Web of Science were searched. Studies were included if they met the predetermined inclusion/exclusion criteria. Data extraction and quality assessment were performed on the included studies. The effects of Wim Hof Method were categorised into physiological or psychological related outcomes and narrative synthesis was conducted. Results: Nine papers were included in this review which consisted of eight individual trials. The findings of this systematic review suggest that the Wim Hof Method may affect the reduction of inflammation in healthy and non-healthy participants as it increases epinephrine levels, causing an increase in interleukin-10 and a decrease in pro-inflammatory cytokines. Additionally, Wim Hof breathing method was suggested to not enhance the performance of an exercise as minute ventilation, tidal volume, and breathing frequency were statistically insignificant. Conclusion: Taken together, the findings of this review show promising use of Wim Hof Method in the inflammatory response category. The focus of future studies should move away from investigating the use of Wim Hof breathing method to enhance exercise performance and towards exploring the benefits of Wim Hof Method in non-healthy participants with inflammatory disorders.