Randomisation and masking
Participants were enrolled through Prolific, which was integrated with the survey software Qualtrics (qualtrics.com). After completing the pre-intervention survey, participants were automatically randomly assigned (1:1) using Qualtrics via block randomisation, to receive either the intervention CB (~ 5.5 bcpm) or placebo CB (12 bcpm). The research team were blinded to randomisation but not to assignment for data analysis, due to limited time and study resources. However, participants were blinded to the study hypothesis and to their allocated intervention. The breathwork technique was referred to as ‘rhythmic breathing’ across both groups, in an attempt to conceal the specific practice being tested.