老年人和 50 岁以上的人在有意和间接接触大自然后的免疫反应和情感状态

有源比较器：Group A: intentional contact with nature

Group A volunteers will take a light walk along the park with green space in a single 1-hour session guided by a Multicomponent Nature-Based Intervention grounded in the "A time with e-Nature" model. This intervention was developed by this same research group and integrates multisensory, aesthetic-emotional, cognitive, and active-engagement dimensions, constituting a structured and replicable protocol.

行为的：Intentional contact with nature

The participants will take a light walk in a park with green spaces guided by research team in a single 1-hour session, based on the Multicomponent Nature-Based Intervention named A time with e-Nature. This intervention integrates multisensory, aesthetic-emotional, cognitive, and active-engagement dimensions.

其他名称：

• A time with e-Nature

有源比较器：Group B: indirect contact with nature

The members of Group B will watch a video with the images of the e-Nature Positive Emotions Photography Database (e-NatPOEM), a database of nature images validated by this same research group for its capacity to evoke positive emotions in a controlled manner. Participants will watch the material in a controlled environment, lasting approximately 45 minutes.

行为的：Indirect contact with nature

The participants will watch a video with validated images of nature from e-Nature Positive Emotions Photography Database (e-NatPOEM).

Participants will watch the material in a controlled environment, lasting approximately 45 minutes.

其他名称：

• e-NatPOEM

Change from Baseline Concentration of Cytokines in Soluble Immune Profile at 30 minutes post intervention, within 48-72 hours post intervention and within 25-35 days post intervention.

Quantify the change from baseline pre intervention in concentration of cytokines in plasma ng/ml (IFN-γ, IL-10, Granzyme A, IL-13, Granzyme B, IL-2, IL-4, IL-6, TNF-α e perforina) in comparison the concentrations between the periods of 30 minutes post intervention, within 48-72 hours post intervention and within 25-35 days post intervention

Change from baseline of Cellular Immune Profile at 30 minutes post intervention, within 48-72 hours post intervention and within 25-25 days post intervention

Quantify the changes from baseline pre intervention of frequency of cellular immune populations and their inhibiting, activating, effector and lytic molecules of subpopulation of lymphocytes and NK cells and their memory status in the blood within the period of 30 minutes post intervention, 48-72 hours and 25-35 days post intervention.

Change from baseline affective states at 30 minutes post intervention, within 48-72 hours post intervention and within 25-35 days post intervention.

Will be applied the Profile of Mood States - POMS. It is one of the most used instruments in psychology to assess the states emotions and mood states, as well as the variation associated with them.

Assesses six domains: Tension-Anxiety, Depression-Dejection, Anger-Hostility, Vigor-Activity, Fatigue-Inertia, and Confusion-Bewilderment. Each item can be rated on a Likert-type frequency scale of sensations, ranging from 0 (not at all) to 4 (extremely). The scale final score indicates the Total Mood Disturbance.