The EndoChill Trial: Evaluating the safety and efficacy of the Wim Hof Method for endometriosis pain

Once enrolled into the study, participants will follow a three-phase study procedure (baseline, intervention, and follow-up) which will entail the following: Baseline Phase: Participants will undergo an eTVUS (transvaginal ultrasound for endometriosis) scan to establish their initial endometriosis lesion characteristics. This will form part of the inclusion and exclusion criteria with only participants that have endometriosis lesions visible by eTVUS included in the study. Participants will complete daily pelvic pain ratings for the duration of the study, specifically using an 11-point numerical rating scale (NRS) via the Ethica app on their mobile device. A second eTVUS will be completed in the week prior to the intervention phase. A blood sample will be collected on the same day as the second eTVUS to assess sympathetic nervous system function, hormone levels, and innate immune responses. Participants will also complete the Pelvic Pain Impact Questionnaire (PPIQ) and Pelvic Pain Psychological Screening Questionnaire (3PSQ) using the Ethica App. These questionnaires will be used to measure physical and psychological impacts of pain associated with endometriosis. The baseline phase of the study will vary in length from 1 to 6 weeks based upon participant randomisation. Intervention Phase: The Wim Hof Method (WHM) is a novel intervention that combines breathing exercises, mindfulness, and cold exposure therapy to improve health outcomes. At the beginning of the intervention phase, participants will attend (in small groups of 4 to 6 people) one training workshop introducing the WHM, including correct technique and safety requirements (3 hours duration). These workshops will be conducted by a trained instructor. Participants will then continue to practice the WHM daily at home for 12 weeks, guided and recorded via the WHM app. In addition, participants will have the option to attend up to 2 x 1-hour supervised WHM sessions per week during the intervention phase. During intervention weeks 6 (mid-intervention) and 12 (end-intervention), participants will attend a supervised WHM session. A blood sample will be collected on each of these visits to assess sympathetic nervous system function, hormone levels, and innate immune responses. Participants will also complete the PPIQ and 3PSQ. Participants will continue recording daily pelvic pain ratings via the Ethica app. Follow-up Phase: Participants will continue recording daily pelvic pain ratings via the Ethica App and engage in WHM via the WHM app for a further 8 weeks after the intervention phase. In the final week of the follow-up phase, participants will undergo an eTVUS scan, blood sample collection to assess sympathetic nervous system function, hormone levels, and innate immune responses, and will complete the PPIQ and 3PSQ. These data will be used to evaluate long-term effects of the WHM intervention. Study locations: The site for eTVUS scanning will be Specialist Imaging Partners in North Adelaide. Blood samples, and completion of the PPIQ and 3PSQ, will also take place here during the baseline and follow-up phases. All WHM workshops, supervised WHM sessions, and the mid- and end-intervention measurements (blood samples, PPIQ and 3PSQ) will take place at the Clinial Research Facility at the University of Adelaide Health and Medical Sciences Building (AHMS) situated on North Terrace, Adelaide CBD.