Effects of green exercise and waterfall aerosol on mucosal immunity and chronic stress. A randomized controlled clinical trial
Carina Grafetstaetter, Paracelsus Medical University of Salzburg (AT)
Green exercise in the protected area of the National Park Hohe Tauern (Austria) and the specific microclimate of alpine waterfalls with high levels of ionized water aerosols has been suggested to trigger beneficial health effects. In the present three-armed randomized controlled clinical study (n=102) we focused on import medical and physiological functions of human health: (i) immune reagibility, (ii) physiological stress response and (iii) stress-related psychological parameters. Methods: 102 participants with moderate to high stress levels (health professionals) were included in the present study. Two groups (n=65) spent an active sojourn with daily GPS controlled hiking tours in the National Park Hohe Tauern (Großkirchheim, Austria). One group was exposed to water aerosol of an alpine waterfall for one hour per day (first arm, n=33), whereas the other group spent the same time at a distant site (second arm, n=32). A third arm (control, n=26) had no intervention (except vaccination) and stayed at home, maintaining their usual lifestyle. The effect of the interventions on the immune system was tested by oral vaccination with an approved cholera vaccine and measuring salivary IgA antibody titers. Lung function was determined by peak expiratory flow measurement. Electric skin conductance, heart rate and adaption of respiration rate were assessed as physiological stress parameters. Psychological stress-related parameters were analyzed by questionnaires and scales. Results: Compared to the control group, both intervention groups (green exercise and green exercise + waterfall) showed improvement of the lung function and of most physiological stress test parameters. Analysis of the mucosal immune response revealed a waterfall-specific beneficial effect with elevated IgA titers in the waterfall-group. In line with these results, exposure to waterfall revealed an additional benefit concerning psychological parameters such as subjective stress perception (measured via visual analog scale), the Global Severity Index (GSI) and the Positive Symptom Total (PST). Conclusion: Our study provides new data that strongly supports a beneficial health effect of green exercise and waterfall microbiota on immune function, physiological and psychological stress parameters. An active sojourn in the protected area National Park Hohe Tauern can be an efficient measure for the prevention of stress and burnout.