The purpose of designing this randomized control trial is to observe the effect of nature-based walk on post-traumatic growth and Psychophysiological alterations associated with it, in traumatic stress among health care providers of Karachi Pakistan. This study is planned to investigate the recreational exposure to the natural environment for the promotion of PTG, in the traumatic stress subjects and to determine whether PTG is associated with psychophysiological alterations, i.e. C-Reactive Protein, Brain Derived Neurotropic Factor, Interleukin-6, Cortisol, and Heart Rate Variability. Subjects who had experienced any traumatic event in the last 12 months will be recruited, and at baseline, the participant will be assessed with Trauma Symptom Checklist 40 to evaluate trauma intensity. Moreover, subjects who had developed PTG or did not have any trauma intensity will be excluded from the study. Blinded treatment will be provided to subjects meeting eligibility criteria and will be randomized into two groups sequentially as they agree to participate. The nature-based walk will be used as intervention vs the control (relax in nature). The study outcomes will be monitored in subjects of both groups at different intervals, i.e. at baseline and 3-month follow-up (post-interventional).

Plan of work

• Enrollment: Those subjects who had experienced any traumatic event in the last 12 months will be enrolled.
• Assessment of eligibility: Subject meeting eligibility criteria will be included in the study.
• Baseline assessment: All the variables, i.e. Post-traumatic growth inventory (PTGI), Trauma symptom checklist-40 (TSC-40), Traumatic stress scale (TSS), C-Reactive protein (CRP), Brain-derived neurotrophic factor (BDNF), Interleukin-6 (IL-6), Cortisol and Heart rate variability (HRV) will be measured at baseline.
• Randomization: Subjects based on eligibility criteria will be randomly allocated to the experimental or control group sequentially as they agree to participate.
• Allocation: A booklet with detailed instructions will be provided to the study subjects according to the groups allocated.
• Follow-up assessment: After 3 months, all the variables measured at the baseline phase will be measured again.
• Statistical Analysis: Pre & post-analysis will be conducted in this phase.

Participants Subjects for the present study will be recruited from 5 Health care organizations based in Karachi, Pakistan. The targeted population includes subjects from diverse ethnicity and considered eligible for participation in the study if they indicated in a pre-screening form that they had experienced a traumatic event. These subjects will be invited to participate in the study through advertisements on the notice board of each center. Written informed consent will be obtained from each study subject after providing detailed information regarding the objectives of the study and its duration.

Randomization Subjects based on eligibility criteria will be randomly allocated to the experimental or control group in the 1:1 ratio. Computer-generated random numbers will be used for randomization. After taking the subject's basic information, a unique code will be provided to each included subject by the study center. The code will be mentioned in each form of each subject.

Interventions • The experimental intervention: In this group, the nature walk will take place in a conserved and by far the largest recreational area of Karachi city. The safari park covering an area of 148 acres (0.60 km2), It has a zoo, geared with woodland, mountain viewing, safari tracks, as well as two natural lakes. The experiment will take place in the afternoon on a 5 km marked area. The duration of the stretching exercise sessions will be of 10 minutes followed by 50 minutes' walk session five times per week (total 12 weeks). participants will be asked to walk at moderate pace.

• The control intervention: Subjects will undergo 12 weeks of nature therapy that includes exposure to natural landscapes. The duration of the sessions will be 60 minutes five times per week. The subjects will be asked to sit and relax in the evening, in the same recreational area which is used for the experimental group.

Inclusion Criteria:

1. Both genders, aged 16-50 years
2. Must be disease free (by their reports), there must be no evidence of any metastatic disease.
3. Fluent in written and spoken the Urdu language (National Language of Pakistan).
4. Experienced any traumatic event in the last 12 months.
5. Informed written consent
6. Being able to walk five times per week. (Participants will be asked to complete the Physical Activity Readiness Questionnaire)

Exclusion Criteria:

1. Subjects who received a structured psychological intervention for at least six months during the last three years performed by a psychologist or psychiatrist will be excluded.
2. Those with a codified psychiatric disorder (according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V) who received Psychopharmacological treatment during the last three years will also be excluded from the study sample.
3. Those subjects who had developed Post Traumatic Growth. (will be evaluated from Post Traumatic Growth Inventory)
4. Those subjects who do not have any trauma intensity. (will be evaluated from Trauma Symptom Checklist 40)
5. Subjects who are at high risk for physical injury during exercise.
6. Self-reported current and regular exercise in nature