2.1. Study design
The current data is part of a larger cross-sectional observational study investigating the effect of physical activity in an alpine environment on mental health in 2016 over a 4 month period. Parts of this study have been published (Ower et al. 2018). The institutional review board (ethics commission of the Medical University of Innsbruck) reviewed and approved the study protocol. After being informed in detail about the study aims and procedures, participants provided informed written consent online by clicking on the consent statement and manually adding the date of consent, prior to study participation. This method of consent was approved by the ethics commission of the Medical University of Innsbruck.
Participants
Participants and recruiting are described in Ower et al. 2018, participant numbers vary slightly compared to the previous publication due to missing data in individual participants. In brief, a total of 1029 participants were recruited to participate in an open online survey. This included healthy participants as well as patients treated at the Department for Psychosomatic Medicine at Innsbruck Medical University. Participants who terminated the questionnaire early (missing data n = 436) who reported implausible values, who screened positively for alcohol abuse only or for an eating disorder only (using physical activity for losing weight) were excluded from the present analysis (Fig. 1). There were 4–13% missing values for individual SAM ratings. The 498 participants included in the present analysis consisted of a group of patients (defined by positive screen on the Patient Health Questionnaire (PHQ, n = 183)) and a group of healthy participants (HC, negative PHQ screening; n = 315).
2.2. Stimuli
Stimuli were alternating neutral pictures (re-staged to official International Affective Picture System (IAPS) pictures (slide no. 6150, 7009, 5661, 5500, 7150)) and alpine stimuli (Fig. 2). Alpine stimuli displayed alpine environments with individuals performing some sort of physical activity therein (e.g. hiking, biking, skiing). Two picture stimuli had to be excluded due to statistical outliers in the ratings. Pictures were displayed for 5 seconds before the page with the emotional analytic ratings appeared. Each stimulus could only be observed once.
2.3. Measures
Socio-demographic parameters included information on age, sex, education and marital status. Mental health was assessed using the German version of Patient Health Questionnaire (Gräfe et al. 2004). Additionally, open text fields were provided for entering psychiatric diagnoses. Resilience was measured using the Brief Resilience Score (BRS) (Smith et al. 2008), self-perceived stress using the Perceived Stress Scale (PSS) (Cohen et al. 1983) and Physical activity using the Global Physical Activity Questionnaire (GPAQ-2) (Bull et al. 2009).
To measure emotional response we used the Self-Assessment Manikin (SAM) 9-point Likert-scale. This scale measures emotional analytics in the three dimensions valence, arousal and dominance (J Lang et al. 2008). The valence scale ranges from a frowning, unhappy (adjectives used in the SAM manual: unhappy, annoyed, unsatisfied, melancholic, despaired, bored; lower values) to a smiling, happy figure (happy, pleased, satisfied, contented, hopeful). The arousal scale displays the lowest value with a calm, eyes-closed figure (relaxed, calm, sluggish, dull, sleepy, unaroused), whilst the highest value is represented by an excited figure (stimulated, excited, frenzied, jittery, wide-awake, aroused). The lowest values in the dominance scale are symbolized by a controlled small figure (controlled, influenced, cared-for, awed, submissive, guided.) whilst highest values are represented by a dominant and oversized figure (controlling, influential, in control, important, dominant, autonomous). After presenting a picture for five seconds participants were asked to rate their emotional reaction in the three dimensions. For alpine stimuli, we added a fourth dimension asking about ones attraction to the situation, labelled motivational direction. The 9 point Likert-scale ranged from “I don’t want to be in this situation” to “I want to be in the situation”.
2.4. Statistical methods
Metric variables were analyzed for normal distribution prior to applying further statistical tests by assessing their skewness, considering values > 0.5 or < -0.5 as deviations from a symmetric distribution requiring non-parametric testing. To compare emotional reactions between overall neutral and alpine pictures we created a mean score for each category. In each category one picture was excluded due to statistical outliers (paraglide in alpine pictures; red wall in neutral pictures). Mean score were calculated for each emotional dimension per person if at least three scores were completed. Group comparisons (patients vs. HC) were performed using t-test, Mann-Whitney U-test and Chi-square test, depending on the variable type and distribution. The relationship between resilience, self-perceived stress, PA and emotional analytics was investigated on a descriptive level by means of correlation analysis. Spearman rank correlation coefficients were used as most the variables involved showed deviations from a normal distribution.