Interview topic guide.

<div> Amidst global challenges like the COVID-19 pandemic and the climate crisis, there’s a pressing need for strategies that improve wellbeing. This study investigates the Wim Hof Method (WHM) as a potential tool for enhancing wellbeing and its influence on related aspects including nature connectedness and health attitudes, including vaccine uptake. We conducted a mixed-methods study involving an online survey with 192 UK-based WHM practitioners and in-depth interviews with 15 of these participants. The focus was on their wellbeing, perceptions of climate change, and decisions regarding vaccine use during the COVID pandemic. Following exclusions, a total of 132 participants were available for quantitative analysis. Findings revealed higher levels of wellbeing among WHM practitioners relative to pre-pandemic (<i>d</i>= 0.78) and pandemic-era (<i>d</i>= 1.32) benchmarks. Notably, nature connectedness was found to mediate the relationship between WHM practice and enhanced wellbeing (<i>p</i><.05, bootstrapped). Thematic analysis yielded seven main themes: the cultivation of positive psychological states, experience of challenging climate-related emotions, improved distress management, heightened sense of connectedness, perceived vulnerability to COVID-19, moral and social responsibility, and the recognition of opportunities for positive change. Vaccine attitudes were nuanced, with some practitioners prioritising public health through vaccination while others leaned towards natural health approaches, reflecting a broader tension between individual beliefs and collective wellbeing. While 73% (96 of 132) of our sample either had received or intended to receive the vaccine, this was lower than the wider UK population at that time (96%). Overall, our findings underscore WHM’s role in not only bolstering human wellbeing during adversity but also highlight opportunities for promoting environmentally sustainable behaviours by reconnecting people to nature. This dual benefit highlights potential for fostering human flourishing as well as environmental stewardship while reinforcing the need for carefully tailored public health strategies that engage with diverse perspectives to maximise both individual and societal resilience. Study registration The study was registered prospectively on August 4, 2021 and registration is available here: <a href="https://doi.org/10.17605/OSF.IO/GSAE9" target="_blank">https://doi.org/10.17605/OSF.IO/GSAE9</a> </div>