8-week Mindfulness Based Stress Reduction (MBSR) intervention protocol, as developed by Stahl & Goldstein (2010). After the training, participants will enter a 12-month phase of regular MBSR-based supervised practice.

This scale comprises 15 items designed to measure the individual's general mindfulness capacity. It uses a 6-point Likert-type response format where 1 = "Almost always" and 6 = "Almost never".Total scores are obtained by averaging each participant's responses to the items, with higher scores meaning a greater mindfulness capacity.

A 10-item questionnaire designed to measure two dimensions of meaning in life: (1) Presence of Meaning (how much respondents feel their lives have meaning), and (2) Search for Meaning (how much respondents strive to find meaning and understanding in their lives). Respondents answer each item on a 7-point Likert-type scale ranging from 1 (Absolutely True) to 7 (Absolutely Untrue). Higher scores represent experiencing higher levels of meaning in life (presence of meaning) and higher levels of search for meaning.

This measure comprises 7 items intended to measure experiential avoidance, that is, an individual's unwillingness to be exposed to and accept difficult inner experiences (e.g., thoughts, feelings, sensations) even when doing so leads to behaving in a manner that could be inconsistent with one's values and goals. Participants rate each item on a 7-point Likert-type scale, with 1 = Never true to 7 = Always true. Total scores are obtained for each participant by averaging his/her responses to the items, with higher scores representing a higher level of experiential avoidance.

The 7-item "Activation" subscale of the Behavioral Activation for Depression Scale (BADS), measures focused, goal-directed activation and completion of planned activities, e.g., "I did things even though they were hard because they fit in with my long-term goals for myself". Responses are made on a 7-point Likert-type scale from 0 = "Not at all" to 6 = "Completely". Items were averaged to obtain a total score for each participant. Higher scores reflect a higher level of behavioral activation.

This instrument consists of 10 items representing positive moods (e.g., interested, enthusiastic, inspired) and 10 items representing negative moods (e.g., irritable, upset, afraid). Participants are asked to rate the extent to which they had recently experienced each of the twenty feelings or emotions on a 5-point Likert-type scale, ranging from 1 = Very slightly or not at all to 5 = Extremely. Two separate total scores corresponding to positive and negative affect are obtained for each participant. Total scores (ranging from 1 to 5) are calculated by averaging each respondent's answers to the ten items included in the positive/negative affect scales, with higher scores indicating experiencing more positive/negative moods.

This questionnaire uses 7 items scored from 1 (never) to 7 (always) on a Likert-type scale.

Total scores are obtained for each participant by averaging his/her responses to the items, with higher scores representing a higher level of cognitive fusion.

Change in psychological flexibility will be measured using Psy-Flex scale (Gloster et al., 2021; Spanish translation by Ruiz Jiménez et al., 2021). This scale uses 6 items scored from 1 (never) to 5 (very often) on a Likert-type scale. Total scores are obtained for each participant, with higher scores representing a higher level of psychological flexibility.

Change in depression and anxiety will be measured using Hospital Anxiety and Depression Scale (HAD-S), (Zigmond & Snaith, 1983; Terol et al., 2007). This scale comprises 14 items intended as a screening instrument to detect possible anxiety (7 items) and depression (7 items problems). Examples items are "I get sudden feelings of panic" (anxiety) and "I have lost interest in my appearance" (depression). Participants respond by selecting 1 of 4 alternatives that are scored from 0 to 3. Scores for anxiety and depression are calculated by adding the individual's responses to the items in each subscale, with higher scores indicating higher levels of anxiety and depression.

Change in mental health self-informed status will be measured using the Mental Health Subscale of the SF-36(v2) Health Survey (Alonso et al., 2003). The Mental Health subscale of the SF-36 Health Survey (Ware et al. 1993; Spanish adaptation by Alonso et al. 1995) is used to identify possible symptoms of depression (e.g., 'Have you felt downhearted and blue?') and anxiety (e.g., 'Have you been a very nervous person?'). This subscale comprises 5 items and uses a 5-point Likert-type response format. Total scores are obtained following instructions provided by Ware et al. (1993). A higher total score (ranging from 1 to 5) indicates a better self-assessment of mental health status.

This scale uses 14 items scored from 0 (never) to 4 (very often) on a Likert-type scale.

Total scores are obtained for each participant, with higher scores representing a higher level of perceived stress.

A single-item measure designed by Dolan et al.(2014) will be used to measure burnout levels. Higher scores (1-5) represent higher levels of burnout.

Basal glucose level is measured in mg/dL (milligrams per decilitre). Reference value: 60 - 100 mg/dL.

Cholesterol level is measured in mg/dL (milligrams per decilitre). Reference value: < 200 mg/dL

Triglyceride levels are measured in mg/dL (milligrams per decilitre). Reference values: < 150 mg/dL After fasting 8 - 10 hours ; < 175 mg/dL Without fasting 8 - 10 hours

HDL-Cholesterol levels are measured in mg/dL (milligrams per decilitre). Reference value: > 40 mg/dL.

LDL-Cholesterol levels are measured in mg/dL (milligrams per decilitre). Reference values: < 116 mg/dL for patients with low CV risk; < 100 mg/dL for patients with moderate CV risk; < 70 mg/dL for patients at high CV risk; < 55 mg/dL for patients with very high CV risk.

Ultrasensitive C-Reactive Protein (CRP) levels are measured in mg/dL (milligrams per decilitre). Reference value: < 0.3 mg/dL

Lipemia index is measured in mg/dL (milligrams per decilitre). Reference values for 5 levels indicating a progressive increase in index intensity: 0 - 50 mg/dL (No); 50 - 100 mg/dL ; 100 - 150 mg/dL; 150 - 200 mg/dL;200 - 9999999 mg/dL (Higher).

Jaundice index is measured in mg/dL (milligrams per decilitre). Reference values for 5 levels indicating a progressive increase in index intensity: 0 - 2 mg/dL (No); 2 - 4 mg/dL; 4 - 10 mg/dL;10 - 20 mg/dL; 20 - 9999999 mg/dL (Higher).

Hemolysis index is measured in mg/dL (milligrams per decilitre). Reference values for 5 levels indicating a progressive increase in index intensity: < 30 mg/dL (No); 30 - 100 mg/dL; 100 - 200 mg/dL; 200 - 500 mg/dL; 500 - 9999999 mg/dL (Higher).

The levels of aspartate aminotransferase (GOT/AST) are measured in U/L (units per liter) at 37ºC. Reference value: 8 - 43 U/L at 37 ºC

Lactate dehydrogenase (LDH) levels are measured in U/L (units per liter) at 37ºC. Reference value: 125 - 220 U/L at 37 ºC

Creatin Kinase (CK) levels levels are measured in U/L (units per liter) at 37ºC. Reference value: < 167 U/L at 37 ºC.