To establish the efficacy and repeatability of a suitable psychological stress test. The Mannheim Multicomponent Stress Test (MMST) is a validated laboratory stress test that combines cognitive, emotional, acoustic and motivational stress components. Despite the test increasing self-reported levels of stress, meaningful changes in saliva cortisol are typically observed in only half of all participants. In addition, the MMST is susceptible to habituation of the cortisol response upon repeated exposures, limiting its current usefulness for repeated measures. Given the multicomponent nature of the MMST, there is potential for components of the test to be manipulated to overcome these limitations i.e., increase the magnitude of the saliva cortisol response and mitigate against habituation effects. In addition, a supplementary topic of interest is to what extent cortisol responses to acute laboratory stress tests, like the MMST, relate to the well described rise in morning cortisol ~30 minutes after awakening. This may be of clinical relevance given that blunted cortisol response upon awakening and in response to acute psychological stress tests have been associated with poor health outcomes.

The primary objective of the current study is to investigate if the MMST elicits a meaningful increase in saliva cortisol.

The secondary objective is to investigate the efficacy of mitigation strategies to overcome habituation to the MMST.

A supplementary objective is to to investigate the relationship between the saliva cortisol response upon awakening and the saliva cortisol response to the MMST.

Inclusion Criteria:

Participants who…

• have read and signed the study informed consent
• are healthy, recreationally active men and women aged 18-35 years
• test negative for coronavirus (COVID-19)
• are willing to provide saliva samples throughout and complete the MMST through the duration of the study
• are using monophasic birth control (women only)

Exclusion Criteria:

Participants who…

• have a recent history or are a current smoker
• are currently taking prescription/Over-the-counter medication
• consume ≥ 91 units of alcohol per month
• have a clinically diagnosed history of cardiovascular and/or metabolic disease including diabetes and abnormal blood pressure
• are pregnant
• have a recent or ongoing viral or bacterial illness in past 4 weeks
• test positive for coronavirus (COVID-19)
• have a clinically diagnosed psychiatric disorder
• have a clinically diagnosed sleeping disorder
• have a clinically diagnosed gambling addiction
• BMI ≥ 30 kg/m2 - calculated in the online health screening questionnaire
• report unusually high levels of recent or ongoing life stress over the last month; as assessed by the perceived stress scale (PSS) i.e. rating ≥ 13 indicates high perception of recent and ongoing life stress
• Endurance trained or engage in ≥3.5 hours of physical activity a week

Saliva samples will be identified by participant identification number only. Technicians assessing levels of biological measures in these samples will be blind to condition.