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Introduction: Previous research suggested differential stress reactivity depending on individuals' coping style, e.g., as classified by the model of coping modes. Specifically, stronger physiological reactivity and weaker subjective stress ratings were found for repressors than for sensitizers. However, it remains to be investigated (i) whether these findings, which are largely based on social stress induction protocols, also generalize to other stressors, (ii) whether repressors vs. sensitizers also exhibit differential stress recovery following the application of a relaxation method, and (iii) which stress reactivity and recovery patterns are seen for the two remaining coping styles, i.e., fluctuating, and non-defensive copers. The current study thus examines stress reactivity in physiology and subjective ratings to a non-social stressor and the subsequent ability to relax for the four coping groups of repressors, sensitizers, fluctuating, and non-defensive copers. Methods: A total of 96 healthy participants took part in a stress induction (Mannheim Multicomponent Stress Test) and a subsequent relaxation intervention. Subjective ratings of stress and relaxation, heart rate (HR), heart rate variability (HRV), and blood pressure were assessed during the experiment. HR and blood pressure are markers of the sympathetic stress response that can be regulated by relaxation, while HRV should increase with relaxation. To investigate long-term relaxation effects, subjective ratings were also assessed on the evening of testing. Results: Despite successful stress induction, no differential responses (baseline to stress, stress to relaxation) were observed between the different coping groups on any of the measures. In contrast, a strong baseline effect was observed that persisted throughout the experiment: In general, fluctuating copers showed lower HR and higher HRV than non-defensive copers, whereas repressors reported lower subjective stress levels and higher levels of relaxation during all study phases. No differences in subjective ratings were observed in the evening of testing. Conclusion: Contrary to previous research, no differential stress reactivity pattern was observed between coping groups, which could be due to the non-social type of stressor employed in this study. The novel finding of physiological baseline differences between fluctuating and non-defensive individuals is of interest and should be further investigated in other stressor types in future research.
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BACKGROUND: Repeated or chronic stress is considered a major source of disease, in terms of both somatic and mental illnesses. The prevention of stress-related disease by interventions for relaxation has thus increased societal relevance. In this randomized controlled non-inferiority trial, we will compare a newly developed virtual reality (VR) environment for relaxation to an active control group applying a freely chosen relaxation method. To test if our VR environment supports relaxation in a situation of acute stress, a standardized stress induction protocol will precede the relaxation phase. METHODS: One hundred healthy participants will be recruited from the University of Siegen and randomly assigned to the VR or the active control group that will be free to choose their own relaxation strategy. The multi-sensory VR includes visual, acoustic, and haptic features to induce a strong feeling of presence. The laboratory testing will comprise a baseline measurement, a stress induction, a relaxation intervention, and a recovery measurement. The primary outcomes are self-reported stress and relaxation measured with a visual analog scale (VAS) at pre- and post-baseline, at the start, middle, and end of the stress induction, at pre- and post-relaxation, at pre- and post-recovery, and in the evening of testing. Secondary outcomes are the physiological parameters, namely heart rate and heart rate variability, tonic skin conductance level as well as the number of non-specific skin conductance responses, systolic and diastolic blood pressure and respiratory rate recorded during the four experimental phases as well as state mood, and state rumination assessed at four time points (pre- and post-stress, post-relaxation, and in the evening of testing). Finally, post-event processing will be assessed after relaxation and in the evening of testing. Repeated measures ANOVAs will be performed to test for statistical effects of group, time, and group × time interaction. DISCUSSION: The newly developed, multi-sensory VR offers an intervention for relaxation without prior training. Its immersive character might increase efficacy compared to other relaxation methods, especially in situations of acute stress. Future directions could be the development of a mobile version of the VR to enhance accessibility for users. To achieve a transfer of training effects to real life, VR components should successively be eliminated until relaxation is practiced without guidance by the VR. TRIAL REGISTRATION: ISRCTN Registry ISRCTN11162338 . Retrospectively registered on January 22, 2021.