The goal of this study is to find out whether an open-label placebo nasal spray can reduce stress among individuals engaging in a high-stress canyon swing. The main questions the study aims to answer are: 1) Does an open-label placebo increase likelihood of participants completing another jump? 2) Does the placebo affect how long it takes participants to jump, reduce the reported stress levels before the jump 3) Does the placebo change how enjoyable participants find the jump?

Researchers will compare participants who receive an open-label placebo nasal spray (a spray that contains no active medication and is clearly described as a placebo) with participants who receive no treatment (control). The aim is to see whether the placebo nasal spray can increase likelihood of participants completing another jump, reduce reported stress and improve participants overall enjoyment of the jump.

Participants will:

• Complete a short questionnaire before they jump
• Either self administer a placebo nasal spray (one spray in each nostril) right before stepping through the gate to jump, or receive no treatment (control).
• Complete a short questionnaire after completing the jump
• Whether they complete another jump will be noted

This randomised controlled trial evaluates whether an open label placebo can increase likelihood of participants completing another jump and reduce stress among individuals engaging in a high-stress canyon swing. The intervention is based on prior research on placebo effects - which suggest that expectations and prior learning can produce meaningful physiological and psychological responses to a treatment - even when individuals are aware they are receiving a placebo, known as an open-label placebo. Open-label placebos challenge traditional assumptions by offering an ethically acceptable way to harness the mechanisms of placebos without deception. Prior research shows that open-label placebos can improve a range of self-reported outcomes including reducing stress, pain, and anxiety.

The study examines the effects of an open-label placebo on stress in a real world setting. The primary objective is to assess whether an open-label placebo nasal spray can increase likelihood of participants completing another jump. Secondary objectives include examining whether the placebo influences reported stress time taken to jump, and ratings of the jump in terms of enjoyment.

Participants who have signed up to complete the Shotover Canyon Swing Queenstown and meet the eligibility criteria are randomly assigned in a 1:1 ratio to one of two study arms; either an open-label placebo group or no-treatment control group. Randomisation is conducted independently using a computer-generated allocation sequence. Participants in the placebo group will self-administer the nasal spray once in each nostril immediately prior to stepping through the gate to jump. The nasal spray is made of a saline solution and is explicitly described as a placebo with no active ingredients. Participants in the control group receive no intervention and continue as normal. Statistical analyses will include independent samples t-tests to compare mean differences in primary and secondary outcomes between groups. Missing data will be addressed using multiple imputation techniques. All eligibility criteria, outcome measures and intervention details are specified in the relevant sections of the clinical trial registration record. This trial contributes to a growing body of research examining the effects of open-label placebos and explores whether these mechanisms extends the research into naturalistic, non-clinical settings.

Inclusion Criteria:

• Signed-up to complete the canyon swing
• Aged 18 years and over
• Able to speak and understand English
• Comfortable being randomised to either the open-label placebo or no-treatment control condition

Exclusion Criteria:

• Under 18 years of age
• Unable to speak or understand English
• Unable to provide informed consent