This pilot study, conducted by the Department of Social Medicine and Epidemiology, Faculty of Medicine, University of Rijeka, and funded by the University of Rijeka (project no. uniri-iskusni-biomed-23-181), evaluated two adjunctive non-pharmacological interventions - an eight-week Mindfulness-Based Living Course (MBLC) and a guided forest bathing (Shinrin-yoku) program - relative to a non-randomized comparison group, in older women with treated arterial hypertension. The study used a non-equivalent, pre-test/post-test quasi-experimental design; allocation was non-randomized, based on geographic catchment area and registration with community patronage nurses, with first-come, first-served enrollment until recruitment targets were met. A total of 60 women over 60 years of age were planned for enrollment: 20 in the MBLC group, 20 in the forest bathing group, and 20 in a comparison group receiving usual care. The MBLC group attended eight weekly two-hour workshops based on the Mindfulness Association (UK) curriculum, led by certified facilitators in Rijeka. The forest bathing group attended three weekly guided sessions of approximately 120-150 minutes each at a forest site near Delnice, Gorski Kotar, led by an FTHub-certified guide following the Forest Therapy Hub (FTHub) Walk Activities Sequence. The comparison group received no structured intervention. Outcomes were assessed at baseline and immediately after each group's intervention period (approximately 8 weeks for MBLC; approximately 3 weeks for forest bathing; a matched interval for the comparison group). The primary outcome was perceived stress (10-item Perceived Stress Scale). Secondary outcomes included chronic-disease self-efficacy, health-related quality of life, systolic and diastolic blood pressure, heart rate, and serum cortisol. Eligible participants were women over 60 with documented, treated arterial hypertension who gave written informed consent; exclusions included age under 60, inability to participate for the study duration, homelessness, a diagnosed psychiatric condition, cognitive impairment, and alcohol or substance dependence. The study was approved by the Ethics Committee of the University of Rijeka, Faculty of Medicine (Class: 007-08/24-01/70; 22 October 2024) and was conducted January-May 2025 in Rijeka and the Gorski Kotar region, Croatia. The study is being registered retrospectively, after data collection was complete.
Background and rationale: Arterial hypertension (AH) is highly prevalent among older women, in whom blood pressure control is influenced by chronic psychosocial stress and often deteriorates after menopause. Despite effective antihypertensive pharmacotherapy, population-level blood pressure control remains suboptimal, creating a need for feasible, low-risk adjuncts to standard care that support self-management and well-being without replacing medication. Current European Society of Hypertension guidance acknowledges a role for stress-reduction approaches within lifestyle management. Two candidate adjunctive approaches were of interest here: mindfulness-based intervention, which targets attentional regulation, non-judgmental awareness, and self-compassion; and guided forest bathing (Shinrin-yoku), a nature-based intervention thought to act through sensory immersion, attentional restoration, and parasympathetic activation. Comparative evidence on structured mindfulness-based versus forest-based adjuncts in older women with treated hypertension, assessed across psychological, quality-of-life, and physiological outcomes together, remains limited. This pilot study was designed to generate effect-size estimates to inform a future adequately powered trial rather than to provide confirmatory tests of effectiveness. Objectives: The general objective was to evaluate and compare the effectiveness of two adjunctive non-pharmacological interventions - an eight-week Mindfulness-Based Living Course (MBLC) and a guided forest bathing intervention - relative to a non-randomized comparison group, in improving perceived stress, chronic-disease self-management self-efficacy, health-related quality of life, and selected physiological parameters among older women with treated arterial hypertension, from baseline to follow-up. Specific research questions addressed: (1) whether MBLC or forest bathing produced a greater reduction in perceived stress than the comparison group; (2) whether either intervention produced greater improvement in chronic-disease self-efficacy; (3) whether either intervention produced greater improvement in health-related quality of life; (4) whether either intervention produced more favorable change in blood pressure, heart rate, or cortisol; and (5) whether effects differed between the two active interventions. Design and allocation: This was a non-equivalent, pre-test/post-test quasi-experimental pilot study with three parallel groups (two intervention groups and one comparison group). Allocation was non-randomized. Randomization was not feasible because the mindfulness workshops and forest bathing sessions were each delivered as a community-based service at fixed sites linked to specific community patronage nurses and required advance scheduling and capacity planning within existing primary-care infrastructure. Participants were therefore allocated pragmatically according to their geographic catchment area and registration with a participating community patronage nurse, and were enrolled consecutively as they expressed interest, on a first-come, first-served basis, until each group's recruitment target was reached. Setting and timeline: The study was conducted from January 2025 to May 2025. Recruitment and the mindfulness workshops took place in Rijeka, Croatia; the forest bathing sessions took place at a forest site near Delnice, in the Gorski Kotar region. Data were collected at two time points for every participant: baseline (T0) and immediately after completion of that participant's assigned intervention period (T1) - approximately 8 weeks after baseline for the MBLC group and approximately 3 weeks after baseline for the forest bathing group, with a matched elapsed interval used for the comparison group. Interventions: The MBLC group attended one two-hour workshop per week for eight weeks (16 structured contact hours), delivered by certified mindfulness facilitators using a structured manual. MBLC is a curriculum developed by the Mindfulness Association (United Kingdom) that cultivates present-moment awareness, compassion, and self-compassion, progressing across sessions from attentional and somatic training toward emotion regulation and compassion-based practice. Participants were encouraged to complete approximately 20-30 minutes of daily home practice, supported by guided audio/video recordings and a workbook; home-practice adherence was not formally tracked. The forest bathing group attended three weekly guided sessions of approximately 120-150 minutes, scheduled within a consistent morning window to limit diurnal variation in physiological outcomes, at the same forest site and along the same predefined route (approximately 1.5-2 km) each time. Sessions were led by a guide certified by the Forest Therapy Hub (FTHub) and followed the FTHub Walk Activities Sequence (introduction/arrival, Mechanical Senses, Chemical Senses, Engage/Direct Exposure activities, Txoko sit-spot, and a closing Circle of Incorporation); no structured home practice was assigned between sessions. The comparison group continued routine general-practitioner follow-up and usual antihypertensive management, with no structured attention-control activity. Outcome assessment: Psychological and quality-of-life outcomes were assessed using validated self-report instruments (detailed in the Outcome Measures section); physiological parameters (blood pressure, heart rate, serum cortisol) were assessed using a validated automated monitor and a single accredited laboratory, with cortisol sampling standardized to a fixed morning window under fasting conditions to limit diurnal variability. Statistical analysis: Baseline comparability across the three groups will be assessed using the chi-square test for categorical variables and the Kruskal-Wallis test for ordinal variables. The primary and secondary outcomes will each be analyzed using a two-way repeated-measures analysis of variance (group x time), with the group x time interaction as the effect of interest; the post hoc Tukey Honestly Significant Difference procedure will be used to control the family-wise error rate for pairwise comparisons within each analysis. Analyses will be performed in IBM SPSS Statistics v28.0 on a complete-case basis (participants with both T0 and T1 data for the outcome in question). Ethical considerations and registration status: The study was approved by the Ethics Committee of the University of Rijeka, Faculty of Medicine (Class: 007-08/24-01/70; Reg. no. 2170-1-42-04-3/1-24-12) on 22 October 2024, and was conducted in accordance with the Declaration of Helsinki, the Nuremberg Code, Croatian health and patients' rights legislation, and Regulation (EU) 2016/679 (GDPR). All participants provided written informed consent. This study is being registered after the completion of data collection (retrospective registration).
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
SUPPORTIVE_CARE
Masking
NONE
Enrollment
60
The mindfulness group attended the Mindfulness-Based Living Course (MBLC), a structured program developed by the Mindfulness Association of the United Kingdom for acquiring the knowledge and skills to practice mindfulness. Workshops were held once weekly for two hours over eight weeks. The eight sessions progressed from an introductory workshop and training the mind and body for one's own well-being, through healthy habits, healthy thinking, healthy nutrition, healthy physical activity (including SMART goal-setting), and healthy relationships, to a final session on living healthily despite a chronic condition, encouraging participants to take an active role in managing their own health and to focus on their own resources rather than on disease symptoms. The workshops were led by a certified MBLC educator at the Department of Social Medicine and Epidemiology, Faculty of Medicine, University of Rijeka.
The forest therapy group took part in a guided forest bathing (Shinrin-yoku) program comprising three organized visits to a forest environment, each lasting for up to three hours, led by a certified forest therapy guide. Sessions took the form of guided immersion walks in forests in the vicinity of Rijeka, delivered as three organized, guided, single-day forest visits. Sessions were led by a certified Forest Bathing guide accredited by the Forest Therapy Hub (FTHub) and followed the FTHub Walk Activities Sequence (introduction/arrival; Mechanical Senses; Chemical Senses; Engage/Direct Exposure activities; Txoko sit-spot; closing Circle of Incorporation). The program involved active participation in guided immersion in the forest environment, intended to allow participants to experience first-hand the benefits of the method, which has been associated internationally with reductions in blood pressure and in stress-hormone levels in blood, saliva, and urine.
University of Rijeka, Faculty of Medicine
Rijeka, Croatia
Perceived stress
The 10-item Perceived Stress Scale (PSS-10; Cohen et al., 1983) was used to assess a person's stress level based on their perception of life as unpredictable, uncontrollable, and overwhelming. The questionnaire includes 10 items rated on a Likert scale (0 = Never, 1 = Almost never, 2 = Sometimes, 3 = Quite often, 4 = Very often). The items are grouped into two factors: the first relates to perceived helplessness, and the second to perceived self-efficacy \[33\]. Higher scores indicate a higher level of perceived stress.
Time frame: Baseline and immediately after completion of the assigned intervention period: up to 8 weeks (MBLC group), up to 3 weeks (forest bathing group), matched interval (comparison group)
Chronic disease self-management self-efficacy
Chronic disease self-management self-efficacy was assessed using the Self-Efficacy for Managing Chronic Diseases 6-item Scale (SEMCD-6). This questionnaire includes six items that measure a person's confidence in controlling fatigue, physical discomfort or pain, emotional difficulties, and other activities related to managing chronic diseases and conditions. The items are rated on a 10-point Likert scale (1 = Not at all confident; 10 = Completely confident). To interpret the scale, the mean value is calculated for at least four of the six items, with higher values indicating a higher level of self-efficacy in man-aging chronic diseases and conditions.
Time frame: Baseline and immediately after completion of the assigned intervention period: up to 8 weeks (MBLC group), up to 3 weeks (forest bathing group), matched interval (comparison group)
Health-related quality of life
Health-related quality of life was assessed using the EuroQol-5 Dimensions-5 Level Ques-tionnaire (EQ-5D-5L). This standardized questionnaire measures subjective health-related quality of life and is commonly used to calculate expected life expectancy adjusted for time spent in illness and disability (Quality-Adjusted Life Year; QALY) to determine the cost-effectiveness of a health intervention. The questionnaire includes five questions addressing mobility, personal care, usual daily activities, pain, and anxiety. Based on participants' responses, the EQ-5D-5L can identify 3,125 different health states.
Time frame: Baseline and immediately after completion of the assigned intervention period: up to 8 weeks (MBLC group), up to 3 weeks (forest bathing group), matched interval (comparison group)
Blood pressure (systolic and diastolic)
Blood pressure and heart rate were measured using a validated blood pressure monitor (Micro-Life BP B3 AFIB, Taipei, Taiwan), following the guidelines of the European Society of Cardiology (ESC) and the European Society of Hypertension (ESH). Before blood pressure measurement, participants sat still for 5 minutes. The blood pressure monitor measured blood pressure three times in succession and displayed the mean value as the result, along with the heart rate. In this study,
Time frame: Baseline and immediately after completion of the assigned intervention period: up to 8 weeks (MBLC group), up to 3 weeks (forest bathing group), matched interval (comparison group)
Cortisol
Blood cortisol levels were measured at two time points: baseline and after the intervention period. To minimize the influence of circadian variation, blood samples for all participants were collected between 08:00 and 09:00 in the morning at both time points to limit diurnal variation, and each participant was sampled within the same one-hour window at baseline and follow-up. Participants were instructed to fast and to avoid strenuous physical activity, alcohol, and acute stressors before sampling Venous blood samples were collected by trained medical personnel at the Analiza Clinic, Prolaz Marije Krucifikse Kozulić 2, 51000 Rijeka, Croatia. Blood was collected using standard venipuncture procedures into appropriate collection tubes for serum cortisol analysis. After clotting, samples were centrifuged according to the laboratory's standard operating procedures, and serum was separated for biochemical analysis. Cortisol concentration was deter-mined using the routine validated la
Time frame: Baseline and immediately after completion of the assigned intervention period: up to 8 weeks (MBLC group), up to 3 weeks (forest bathing group), matched interval (comparison group)
Heart rate
Heart rate was measured using a validated blood pressure monitor (Micro-Life BP B3 AFIB, Taipei, Taiwan). Before heart rate measurement, participants sat still for 5 minutes. The blood pressure monitor measured heart rate together with blood pressure three times in succession and displayed the mean value as the result.
Time frame: Baseline and immediately after completion of the assigned intervention period: up to 8 weeks (MBLC group), up to 3 weeks (forest bathing group), matched interval (comparison group)
Self-rated health status on the day of questionnaire completion
To determine the participants' self-rated health status on the day of questionnaire completion, the EuroQol Visual Analogue Scale (EQ-VAS) was used. The instrument consists of a vertical, thermometer-like line numbered from 0 to 100 with specific verbal descriptors at each endpoint: 100 (Top): "The best health you can imagine" and 0 (Bottom): "The worst health you can imagine".
Time frame: Baseline and immediately after completion of the assigned intervention period: up to 8 weeks (MBLC group), up to 3 weeks (forest bathing group), matched interval (comparison group)
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