Physiological and Mood Changes After Walking in Green Spaces. A Comparison of Environments.

Natural environments, and more specifically forest environments, have shown in the last decade a growing interest as a protection against the frenetic pace of life of a large part of the urban population in developed countries, where symptoms related to stress and anxiety are associated with an increasingly frequent state of sub-health. The investigators propose to perform a randomized crossover study to analyze the effects of a walk in the forest on physiological and psychological markers related to autonomic nervous system activity in healthy adult. In addition, the investigators intend to observe whether the characteristics and perceptions of the forest environment could affect the results obtained in these markers using a scale created for this purpose. Participants will be healthy adults with no history of serious physical or psychological illnesses, who will be exposed to three forest environments. Physiological markers will be measured, including heart rate variability, which will be measured with a heart rate sensor that will monitor data throughout the exposure period, and heart rate and systolic and diastolic blood pressure, which will be measured with an automated device before and after each exposure. Before and after the walk through each of the forest environments, mood will be measured using the POMS scale, and our scale will be used to measure the perceived environmental quality after exposure to each environment. In addition to the walk through the three forest environments, a control environment on an indoor treadmill will be used as a comparator, where distance, slope and walking speed will be adjusted to replicate the intensity and physical demand of the three outdoor routes. The four interventions will be organized to create three different exposure sequences. Each exposure sequence will be randomly assigned to a different group. In turn, each participant will be randomly assigned to one of the three groups, so that all participants will undergo all four interventions in a repeated measures design. Our hypothesis supports the idea that exposure to forest environments causes changes in physiological parameters and mood associated with positive regulation for health and for the autonomic nervous system in healthy adults compared to a neutral non-forest environment. As a second hypothesis, environmental characteristics as well as the perceived quality of the forest environment would be related to the magnitude of such changes associated with autonomic nervous system regulation and mood in healthy adults.