The waiting list group will receive the intervention after the primary outcome is measured. No intervention was provided before this point.

On a weekly basis, participants will receive reminder emails highlighting specific risk factors associated with parental burnout. These risk factors include parental perfectionism, low emotional intelligence, lack of parenting practices, excessive responsibilities, and lack of support. Each week, the reminder email will cover a different topic, providing participants with relevant information.

Every week, participants will receive two reminder emails: one with a list of activities to complete during the week and another containing information about parental burnout. This approach aims to support participants in staying engaged with the program.

The participants will have the option to join a WhatsApp group with 25 other members from the specific group to receive daily greetings, group support, and have general doubts resolved.

As part of the mindfulness intervention, participants are required to write in a journal every day with the purpose of cultivating awareness of bodily sensations, emotions, thoughts, and impulses. Each week, the journaling topic focuses on a different area, including pleasant experiences, unpleasant experiences, needs and resources, communication difficulties, and sharing resources. In contrast, the control group's journaling activity involves free writing about everyday issues, thoughts, and ideas.

Participants receive a 10 and 20-minute relaxation exercise guide called the Jacobson Progressive Relaxation, which they are expected to practice daily.

The Parental Burnout Assessment (PBA) is a questionnaire validated in Chile that consists of 23 items and evaluates the four main symptoms of parental burnout: emotional exhaustion (9 items), contrast with the parent's previous self (6 items; e.g., I tell myself that I am no longer the parent I used to be), loss of pleasure in the parenting role (5 items; e.g., I don't enjoy spending time with my children), and emotional distancing from children (3 items; e.g., I can no longer show my children that I love them). A 7-point frequency scale is used, with higher scores indicating higher levels of parental burnout. The score is calculated by adding up the scores of the items, with a maximum score of 138 points (Roskam et al., 2021).

The Parental Burnout Assessment (PBA) is a questionnaire validated in Chile that consists of 23 items and evaluates the four main symptoms of parental burnout: emotional exhaustion (9 items), contrast with the parent's previous self (6 items; e.g., I tell myself that I am no longer the parent I used to be), loss of pleasure in the parenting role (5 items; e.g., I don't enjoy spending time with my children), and emotional distancing from children (3 items; e.g., I can no longer show my children that I love them). A 7-point frequency scale is used, with higher scores indicating higher levels of parental burnout. The score is calculated by adding up the scores of the items, with a maximum score of 138 points (Roskam et al., 2021).

The Parental Burnout Assessment (PBA) is a questionnaire validated in Chile that consists of 23 items and evaluates the four main symptoms of parental burnout: emotional exhaustion (9 items), contrast with the parent's previous self (6 items; e.g., I tell myself that I am no longer the parent I used to be), loss of pleasure in the parenting role (5 items; e.g., I don't enjoy spending time with my children), and emotional distancing from children (3 items; e.g., I can no longer show my children that I love them). A 7-point frequency scale is used, with higher scores indicating higher levels of parental burnout. The score is calculated by adding up the scores of the items, with a maximum score of 138 points (Roskam et al., 2021).

The 15-item Five Facets of Mindfulness Questionnaire (FFMQ-15) validated in Chile (Villalon et al, in press) was used.

The items evaluate the level of certainty of a statement on a Likert scale ranging from 1 (never or very rarely true) to 5 (very often or always true), worded both positively and negatively. This questionnaire assesses five dimensions or factors of the mindfulness construct (Observing, Describe, Acting with attention/awareness, Non-judgment of inner experience and Non-reactivity to inner experience). A higher score indicates a higher level of mindfulness.

The 15-item Five Facets of Mindfulness Questionnaire (FFMQ-15) validated in Chile (Villalon et al, in press) was used.

The items evaluate the level of certainty of a statement on a Likert scale ranging from 1 (never or very rarely true) to 5 (very often or always true), worded both positively and negatively. This questionnaire assesses five dimensions or factors of the mindfulness construct (Observing, Describe, Acting with attention/awareness, Non-judgment of inner experience and Non-reactivity to inner experience). A higher score indicates a higher level of mindfulness.

The 15-item Five Facets of Mindfulness Questionnaire (FFMQ-15) validated in Chile (Villalon et al, in press) was used.

The items evaluate the level of certainty of a statement on a Likert scale ranging from 1 (never or very rarely true) to 5 (very often or always true), worded both positively and negatively. This questionnaire assesses five dimensions or factors of the mindfulness construct (Observing, Describe, Acting with attention/awareness, Non-judgment of inner experience and Non-reactivity to inner experience). A higher score indicates a higher level of mindfulness.

The 15-item Five Facets of Mindfulness Questionnaire (FFMQ-15) validated in Chile (Villalon et al, in press) was used.

The items evaluate the level of certainty of a statement on a Likert scale ranging from 1 (never or very rarely true) to 5 (very often or always true), worded both positively and negatively. This questionnaire assesses five dimensions or factors of the mindfulness construct (Observing, Describe, Acting with attention/awareness, Non-judgment of inner experience and Non-reactivity to inner experience). A higher score indicates a higher level of mindfulness.

The 15-item Five Facets of Mindfulness Questionnaire (FFMQ-15) validated in Chile (Villalon et al, in press) was used.

The items evaluate the level of certainty of a statement on a Likert scale ranging from 1 (never or very rarely true) to 5 (very often or always true), worded both positively and negatively. This questionnaire assesses five dimensions or factors of the mindfulness construct (Observing, Describe, Acting with attention/awareness, Non-judgment of inner experience and Non-reactivity to inner experience). A higher score indicates a higher level of mindfulness.

The 15-item Five Facets of Mindfulness Questionnaire (FFMQ-15) validated in Chile (Villalon et al, in press) was used.

The items evaluate the level of certainty of a statement on a Likert scale ranging from 1 (never or very rarely true) to 5 (very often or always true), worded both positively and negatively. This questionnaire assesses five dimensions or factors of the mindfulness construct (Observing, Describe, Acting with attention/awareness, Non-judgment of inner experience and Non-reactivity to inner experience). A higher score indicates a higher level of mindfulness.

The UWES-9 Spanish version (Schaufeli & Bakker, 2003) was used to assess work engagement. This scale consists of 3 items per dimension, which are vigor, dedication, and absorption (Table 1). Vigor is evaluated through the following 3 items, which refer to high levels of energy and resilience, the willingness to exert effort, not getting tired easily, and persistence in the face of difficulties. Dedication is evaluated through 3 items that refer to the sense or meaning of work, feeling excited and proud of one's work, and feeling inspired and challenged by work. Absorption is evaluated through 3 items that refer to being happily immersed in one's work and having difficulty leaving it, such that time passes quickly and there is forgetfulness of everything else around. The higher the score, the higher the level of work engagement.

The UWES-9 Spanish version (Schaufeli & Bakker, 2003) was used to assess work engagement. This scale consists of 3 items per dimension, which are vigor, dedication, and absorption (Table 1). Vigor is evaluated through the following 3 items, which refer to high levels of energy and resilience, the willingness to exert effort, not getting tired easily, and persistence in the face of difficulties. Dedication is evaluated through 3 items that refer to the sense or meaning of work, feeling excited and proud of one's work, and feeling inspired and challenged by work. Absorption is evaluated through 3 items that refer to being happily immersed in one's work and having difficulty leaving it, such that time passes quickly and there is forgetfulness of everything else around. The higher the score, the higher the level of work engagement.

The UWES-9 Spanish version (Schaufeli & Bakker, 2003) was used to assess work engagement. This scale consists of 3 items per dimension, which are vigor, dedication, and absorption (Table 1). Vigor is evaluated through the following 3 items, which refer to high levels of energy and resilience, the willingness to exert effort, not getting tired easily, and persistence in the face of difficulties. Dedication is evaluated through 3 items that refer to the sense or meaning of work, feeling excited and proud of one's work, and feeling inspired and challenged by work. Absorption is evaluated through 3 items that refer to being happily immersed in one's work and having difficulty leaving it, such that time passes quickly and there is forgetfulness of everything else around. The higher the score, the higher the level of work engagement.

The UWES-9 Spanish version (Schaufeli & Bakker, 2003) was used to assess work engagement. This scale consists of 3 items per dimension, which are vigor, dedication, and absorption (Table 1). Vigor is evaluated through the following 3 items, which refer to high levels of energy and resilience, the willingness to exert effort, not getting tired easily, and persistence in the face of difficulties. Dedication is evaluated through 3 items that refer to the sense or meaning of work, feeling excited and proud of one's work, and feeling inspired and challenged by work. Absorption is evaluated through 3 items that refer to being happily immersed in one's work and having difficulty leaving it, such that time passes quickly and there is forgetfulness of everything else around. The higher the score, the higher the level of work engagement.

The UWES-9 Spanish version (Schaufeli & Bakker, 2003) was used to assess work engagement. This scale consists of 3 items per dimension, which are vigor, dedication, and absorption (Table 1). Vigor is evaluated through the following 3 items, which refer to high levels of energy and resilience, the willingness to exert effort, not getting tired easily, and persistence in the face of difficulties. Dedication is evaluated through 3 items that refer to the sense or meaning of work, feeling excited and proud of one's work, and feeling inspired and challenged by work. Absorption is evaluated through 3 items that refer to being happily immersed in one's work and having difficulty leaving it, such that time passes quickly and there is forgetfulness of everything else around. The higher the score, the higher the level of work engagement.

The UWES-9 Spanish version (Schaufeli & Bakker, 2003) was used to assess work engagement. This scale consists of 3 items per dimension, which are vigor, dedication, and absorption (Table 1). Vigor is evaluated through the following 3 items, which refer to high levels of energy and resilience, the willingness to exert effort, not getting tired easily, and persistence in the face of difficulties. Dedication is evaluated through 3 items that refer to the sense or meaning of work, feeling excited and proud of one's work, and feeling inspired and challenged by work. Absorption is evaluated through 3 items that refer to being happily immersed in one's work and having difficulty leaving it, such that time passes quickly and there is forgetfulness of everything else around. The higher the score, the higher the level of work engagement.

The balance between risks and resources was measured via the BR scale developed by Mikolajczak & Roskam (2018). This scale measures the balance between the risks and resources that people have in their role as a parent. Each item is responded in a bipolar scale from -5 to +5 (going through 0). The negative pole represents a risk, while the positive pole represents a resource. A global score is composed by adding 39 items, with negative scores indicating a larger presence of risks and positive scores indicating a larger presence of resources. Moreover, each of the 39 items can be categorized as either a "common" or "specific" antecedent to parental burnout. There are 14 common antecedents and refer to general variables that could enhance parental burnout, such as finding it difficult to reconcile family and professional life. In turn, there are 15 specific antecedents to parental burnout, such as feeling that one does not have the competencies to be a good parent.

The balance between risks and resources was measured via the BR scale developed by Mikolajczak & Roskam (2018). This scale measures the balance between the risks and resources that people have in their role as a parent. Each item is responded in a bipolar scale from -5 to +5 (going through 0). The negative pole represents a risk, while the positive pole represents a resource. A global score is composed by adding 39 items, with negative scores indicating a larger presence of risks and positive scores indicating a larger presence of resources. Moreover, each of the 39 items can be categorized as either a "common" or "specific" antecedent to parental burnout. There are 14 common antecedents and refer to general variables that could enhance parental burnout, such as finding it difficult to reconcile family and professional life. In turn, there are 15 specific antecedents to parental burnout, such as feeling that one does not have the competencies to be a good parent.

The balance between risks and resources was measured via the BR scale developed by Mikolajczak & Roskam (2018). This scale measures the balance between the risks and resources that people have in their role as a parent. Each item is responded in a bipolar scale from -5 to +5 (going through 0). The negative pole represents a risk, while the positive pole represents a resource. A global score is composed by adding 39 items, with negative scores indicating a larger presence of risks and positive scores indicating a larger presence of resources. Moreover, each of the 39 items can be categorized as either a "common" or "specific" antecedent to parental burnout. There are 14 common antecedents and refer to general variables that could enhance parental burnout, such as finding it difficult to reconcile family and professional life. In turn, there are 15 specific antecedents to parental burnout, such as feeling that one does not have the competencies to be a good parent.

To measure general health, we used a scale called EQ-5D (Olivares-Tirado, 2006), which is commonly used in Chile to assess the impact of health-related interventions. This scale looks at five areas of health: mobility, personal care, ability to do regular activities (e.g., work, study, etc.), physical pain, and anxiety/depression. For each area, participants chose from three options that indicate how much difficulty they have: no difficulty, some difficulty, or unable to do it. Each option was given a score from 0 to 2, with 0 meaning no problems and 2 meaning a lot of problems.

To measure general health, we used a scale called EQ-5D (Olivares-Tirado, 2006), which is commonly used in Chile to assess the impact of health-related interventions. This scale looks at five areas of health: mobility, personal care, ability to do regular activities (e.g., work, study, etc.), physical pain, and anxiety/depression. For each area, participants chose from three options that indicate how much difficulty they have: no difficulty, some difficulty, or unable to do it. Each option was given a score from 0 to 2, with 0 meaning no problems and 2 meaning a lot of problems.

To measure general health, we used a scale called EQ-5D (Olivares-Tirado, 2006), which is commonly used in Chile to assess the impact of health-related interventions. This scale looks at five areas of health: mobility, personal care, ability to do regular activities (e.g., work, study, etc.), physical pain, and anxiety/depression. For each area, participants chose from three options that indicate how much difficulty they have: no difficulty, some difficulty, or unable to do it. Each option was given a score from 0 to 2, with 0 meaning no problems and 2 meaning a lot of problems.

To measure general health, we used a scale called EQ-5D (Olivares-Tirado, 2006), which is commonly used in Chile to assess the impact of health-related interventions. This scale looks at five areas of health: mobility, personal care, ability to do regular activities (e.g., work, study, etc.), physical pain, and anxiety/depression. For each area, participants chose from three options that indicate how much difficulty they have: no difficulty, some difficulty, or unable to do it. Each option was given a score from 0 to 2, with 0 meaning no problems and 2 meaning a lot of problems.

To measure general health, we used a scale called EQ-5D (Olivares-Tirado, 2006), which is commonly used in Chile to assess the impact of health-related interventions. This scale looks at five areas of health: mobility, personal care, ability to do regular activities (e.g., work, study, etc.), physical pain, and anxiety/depression. For each area, participants chose from three options that indicate how much difficulty they have: no difficulty, some difficulty, or unable to do it. Each option was given a score from 0 to 2, with 0 meaning no problems and 2 meaning a lot of problems.

To measure general health, we used a scale called EQ-5D (Olivares-Tirado, 2006), which is commonly used in Chile to assess the impact of health-related interventions. This scale looks at five areas of health: mobility, personal care, ability to do regular activities (e.g., work, study, etc.), physical pain, and anxiety/depression. For each area, participants chose from three options that indicate how much difficulty they have: no difficulty, some difficulty, or unable to do it. Each option was given a score from 0 to 2, with 0 meaning no problems and 2 meaning a lot of problems.

For burnout we only used the emotional exhaustion scale translated by Olivares-Faúndez and colleagues (2014). Emotional exhaustion is composed of 7 items responded with a 5-point Likert scale representing the extent to which participants agree or disagree with a series of statement about their work. This scale measures the extent to which people feel emotionally exhausted and drained by their work, and high scores represent high levels of burnout. Example items are the extent to which participants feel "emotional drained at work", "that they are working too much", and "completely worn out at the end of the day".

For burnout we only used the emotional exhaustion scale translated by Olivares-Faúndez and colleagues (2014). Emotional exhaustion is composed of 7 items responded with a 5-point Likert scale representing the extent to which participants agree or disagree with a series of statement about their work. This scale measures the extent to which people feel emotionally exhausted and drained by their work, and high scores represent high levels of burnout. Example items are the extent to which participants feel "emotional drained at work", "that they are working too much", and "completely worn out at the end of the day".

For burnout we only used the emotional exhaustion scale translated by Olivares-Faúndez and colleagues (2014). Emotional exhaustion is composed of 7 items responded with a 5-point Likert scale representing the extent to which participants agree or disagree with a series of statement about their work. This scale measures the extent to which people feel emotionally exhausted and drained by their work, and high scores represent high levels of burnout. Example items are the extent to which participants feel "emotional drained at work", "that they are working too much", and "completely worn out at the end of the day".

For burnout we only used the emotional exhaustion scale translated by Olivares-Faúndez and colleagues (2014). Emotional exhaustion is composed of 7 items responded with a 5-point Likert scale representing the extent to which participants agree or disagree with a series of statement about their work. This scale measures the extent to which people feel emotionally exhausted and drained by their work, and high scores represent high levels of burnout. Example items are the extent to which participants feel "emotional drained at work", "that they are working too much", and "completely worn out at the end of the day".

For burnout we only used the emotional exhaustion scale translated by Olivares-Faúndez and colleagues (2014). Emotional exhaustion is composed of 7 items responded with a 5-point Likert scale representing the extent to which participants agree or disagree with a series of statement about their work. This scale measures the extent to which people feel emotionally exhausted and drained by their work, and high scores represent high levels of burnout. Example items are the extent to which participants feel "emotional drained at work", "that they are working too much", and "completely worn out at the end of the day".

For burnout we only used the emotional exhaustion scale translated by Olivares-Faúndez and colleagues (2014). Emotional exhaustion is composed of 7 items responded with a 5-point Likert scale representing the extent to which participants agree or disagree with a series of statement about their work. This scale measures the extent to which people feel emotionally exhausted and drained by their work, and high scores represent high levels of burnout. Example items are the extent to which participants feel "emotional drained at work", "that they are working too much", and "completely worn out at the end of the day".

scale. The scale has 11 items, responded with a 5-point Likert scale representing the extent to which participants agree or disagree with a series of statements about themselves. Higher values denote higher levels of decentering. This scale measures the extent to which participants can detach themselves from their own thoughts and experiences, and observe them from afar. Example items are: "I am able to accept myself", "I can slow my thoughts down in moments of stress", and "I can observe unpleasant feelings without being dragged into them".

scale. The scale has 11 items, responded with a 5-point Likert scale representing the extent to which participants agree or disagree with a series of statements about themselves. Higher values denote higher levels of decentering. This scale measures the extent to which participants can detach themselves from their own thoughts and experiences, and observe them from afar. Example items are: "I am able to accept myself", "I can slow my thoughts down in moments of stress", and "I can observe unpleasant feelings without being dragged into them".

scale. The scale has 11 items, responded with a 5-point Likert scale representing the extent to which participants agree or disagree with a series of statements about themselves. Higher values denote higher levels of decentering. This scale measures the extent to which participants can detach themselves from their own thoughts and experiences, and observe them from afar. Example items are: "I am able to accept myself", "I can slow my thoughts down in moments of stress", and "I can observe unpleasant feelings without being dragged into them".

scale. The scale has 11 items, responded with a 5-point Likert scale representing the extent to which participants agree or disagree with a series of statements about themselves. Higher values denote higher levels of decentering. This scale measures the extent to which participants can detach themselves from their own thoughts and experiences, and observe them from afar. Example items are: "I am able to accept myself", "I can slow my thoughts down in moments of stress", and "I can observe unpleasant feelings without being dragged into them".

scale. The scale has 11 items, responded with a 5-point Likert scale representing the extent to which participants agree or disagree with a series of statements about themselves. Higher values denote higher levels of decentering. This scale measures the extent to which participants can detach themselves from their own thoughts and experiences, and observe them from afar. Example items are: "I am able to accept myself", "I can slow my thoughts down in moments of stress", and "I can observe unpleasant feelings without being dragged into them".

scale. The scale has 11 items, responded with a 5-point Likert scale representing the extent to which participants agree or disagree with a series of statements about themselves. Higher values denote higher levels of decentering. This scale measures the extent to which participants can detach themselves from their own thoughts and experiences, and observe them from afar. Example items are: "I am able to accept myself", "I can slow my thoughts down in moments of stress", and "I can observe unpleasant feelings without being dragged into them".

We used a Spanish version of a scale to measure emotional regulation Cabello et al., 2013), which has two dimensions: cognitive change and suppression. Cognitive change is measured with 6 items that ask how much participants change their thinking to improve their mood. Suppression is measured with 4 items that ask how much participants control their emotions by not expressing them. Both dimensions use a 5-point Likert scale to rate agreement with statements about themselves. Higher scores indicate more cognitive change or suppression. Example items include "I control my emotions by changing my way of thinking about the situation I am in" for cognitive change and "I keep my emotions to myself" for suppression.

We used a Spanish version of a scale to measure emotional regulation Cabello et al., 2013), which has two dimensions: cognitive change and suppression. Cognitive change is measured with 6 items that ask how much participants change their thinking to improve their mood. Suppression is measured with 4 items that ask how much participants control their emotions by not expressing them. Both dimensions use a 5-point Likert scale to rate agreement with statements about themselves. Higher scores indicate more cognitive change or suppression. Example items include "I control my emotions by changing my way of thinking about the situation I am in" for cognitive change and "I keep my emotions to myself" for suppression.

We used a Spanish version of a scale to measure emotional regulation Cabello et al., 2013), which has two dimensions: cognitive change and suppression. Cognitive change is measured with 6 items that ask how much participants change their thinking to improve their mood. Suppression is measured with 4 items that ask how much participants control their emotions by not expressing them. Both dimensions use a 5-point Likert scale to rate agreement with statements about themselves. Higher scores indicate more cognitive change or suppression. Example items include "I control my emotions by changing my way of thinking about the situation I am in" for cognitive change and "I keep my emotions to myself" for suppression.

We used a Spanish version of a scale to measure emotional regulation Cabello et al., 2013), which has two dimensions: cognitive change and suppression. Cognitive change is measured with 6 items that ask how much participants change their thinking to improve their mood. Suppression is measured with 4 items that ask how much participants control their emotions by not expressing them. Both dimensions use a 5-point Likert scale to rate agreement with statements about themselves. Higher scores indicate more cognitive change or suppression. Example items include "I control my emotions by changing my way of thinking about the situation I am in" for cognitive change and "I keep my emotions to myself" for suppression.

We used a Spanish version of a scale to measure emotional regulation Cabello et al., 2013), which has two dimensions: cognitive change and suppression. Cognitive change is measured with 6 items that ask how much participants change their thinking to improve their mood. Suppression is measured with 4 items that ask how much participants control their emotions by not expressing them. Both dimensions use a 5-point Likert scale to rate agreement with statements about themselves. Higher scores indicate more cognitive change or suppression. Example items include "I control my emotions by changing my way of thinking about the situation I am in" for cognitive change and "I keep my emotions to myself" for suppression.

We used a Spanish version of a scale to measure emotional regulation Cabello et al., 2013), which has two dimensions: cognitive change and suppression. Cognitive change is measured with 6 items that ask how much participants change their thinking to improve their mood. Suppression is measured with 4 items that ask how much participants control their emotions by not expressing them. Both dimensions use a 5-point Likert scale to rate agreement with statements about themselves. Higher scores indicate more cognitive change or suppression. Example items include "I control my emotions by changing my way of thinking about the situation I am in" for cognitive change and "I keep my emotions to myself" for suppression.

We used a Spanish version of a Big-Five scale to measure personality (Ortet et al., 2020). Although the Big-Five comprises 5 dimensions, we used only two: extraversion and neuroticism. Extraversion is measured with 6 items that ask participants the extent to which they are extraverted, assertive, and sociable. Neuroticism is measured with 6 items that ask participants the extent to which they tend to worry too much and tend to get depressed easily. Both dimensions use a 5-point Likert scale to rate agreement with statements about themselves. Higher scores indicate more extraversion and neuroticism. Example items are "I am extraverted, sociable" for extraversion and "I worry too much" for neuroticism.

We used a Spanish version of a Big-Five scale to measure personality (Ortet et al., 2020). Although the Big-Five comprises 5 dimensions, we used only two: extraversion and neuroticism. Extraversion is measured with 6 items that ask participants the extent to which they are extraverted, assertive, and sociable. Neuroticism is measured with 6 items that ask participants the extent to which they tend to worry too much and tend to get depressed easily. Both dimensions use a 5-point Likert scale to rate agreement with statements about themselves. Higher scores indicate more extraversion and neuroticism. Example items are "I am extraverted, sociable" for extraversion and "I worry too much" for neuroticism.

We used a Spanish version of a Big-Five scale to measure personality (Ortet et al., 2020). Although the Big-Five comprises 5 dimensions, we used only two: extraversion and neuroticism. Extraversion is measured with 6 items that ask participants the extent to which they are extraverted, assertive, and sociable. Neuroticism is measured with 6 items that ask participants the extent to which they tend to worry too much and tend to get depressed easily. Both dimensions use a 5-point Likert scale to rate agreement with statements about themselves. Higher scores indicate more extraversion and neuroticism. Example items are "I am extraverted, sociable" for extraversion and "I worry too much" for neuroticism.

We used a Spanish version of a Big-Five scale to measure personality (Ortet et al., 2020). Although the Big-Five comprises 5 dimensions, we used only two: extraversion and neuroticism. Extraversion is measured with 6 items that ask participants the extent to which they are extraverted, assertive, and sociable. Neuroticism is measured with 6 items that ask participants the extent to which they tend to worry too much and tend to get depressed easily. Both dimensions use a 5-point Likert scale to rate agreement with statements about themselves. Higher scores indicate more extraversion and neuroticism. Example items are "I am extraverted, sociable" for extraversion and "I worry too much" for neuroticism.

We used a Spanish version of a Big-Five scale to measure personality (Ortet et al., 2020). Although the Big-Five comprises 5 dimensions, we used only two: extraversion and neuroticism. Extraversion is measured with 6 items that ask participants the extent to which they are extraverted, assertive, and sociable. Neuroticism is measured with 6 items that ask participants the extent to which they tend to worry too much and tend to get depressed easily. Both dimensions use a 5-point Likert scale to rate agreement with statements about themselves. Higher scores indicate more extraversion and neuroticism. Example items are "I am extraverted, sociable" for extraversion and "I worry too much" for neuroticism.

We used a Spanish version of a Big-Five scale to measure personality (Ortet et al., 2020). Although the Big-Five comprises 5 dimensions, we used only two: extraversion and neuroticism. Extraversion is measured with 6 items that ask participants the extent to which they are extraverted, assertive, and sociable. Neuroticism is measured with 6 items that ask participants the extent to which they tend to worry too much and tend to get depressed easily. Both dimensions use a 5-point Likert scale to rate agreement with statements about themselves. Higher scores indicate more extraversion and neuroticism. Example items are "I am extraverted, sociable" for extraversion and "I worry too much" for neuroticism.

Job resources represent characteristic of the job that allow employees to cope with demands and help them flourish in their jobs. To evaluate job resources, we employed the Psychosocial Factors Questionnaire (PSF-Q75), which was validated in Spanish by Madrid and colleagues (2020). From the range of available resources, we selected three to assess, specifically, task autonomy (three items), social support (six items), and significance (three items). Our aim in choosing these resources was to represent three distinct categories of job resources, namely, task resources (autonomy), social resources (social support), and job meaning (significance). The questionnaire employed a 5-point Likert scale, which asked participants to indicate the extent to which they agreed or disagreed with various statements about their jobs. Higher scores indicated greater levels of job resources.

Job resources represent characteristic of the job that allow employees to cope with demands and help them flourish in their jobs. To evaluate job resources, we employed the Psychosocial Factors Questionnaire (PSF-Q75), which was validated in Spanish by Madrid and colleagues (2020). From the range of available resources, we selected three to assess, specifically, task autonomy (three items), social support (six items), and significance (three items). Our aim in choosing these resources was to represent three distinct categories of job resources, namely, task resources (autonomy), social resources (social support), and job meaning (significance). The questionnaire employed a 5-point Likert scale, which asked participants to indicate the extent to which they agreed or disagreed with various statements about their jobs. Higher scores indicated greater levels of job resources.

Job resources represent characteristic of the job that allow employees to cope with demands and help them flourish in their jobs. To evaluate job resources, we employed the Psychosocial Factors Questionnaire (PSF-Q75), which was validated in Spanish by Madrid and colleagues (2020). From the range of available resources, we selected three to assess, specifically, task autonomy (three items), social support (six items), and significance (three items). Our aim in choosing these resources was to represent three distinct categories of job resources, namely, task resources (autonomy), social resources (social support), and job meaning (significance). The questionnaire employed a 5-point Likert scale, which asked participants to indicate the extent to which they agreed or disagreed with various statements about their jobs. Higher scores indicated greater levels of job resources.

Job resources represent characteristic of the job that allow employees to cope with demands and help them flourish in their jobs. To evaluate job resources, we employed the Psychosocial Factors Questionnaire (PSF-Q75), which was validated in Spanish by Madrid and colleagues (2020). From the range of available resources, we selected three to assess, specifically, task autonomy (three items), social support (six items), and significance (three items). Our aim in choosing these resources was to represent three distinct categories of job resources, namely, task resources (autonomy), social resources (social support), and job meaning (significance). The questionnaire employed a 5-point Likert scale, which asked participants to indicate the extent to which they agreed or disagreed with various statements about their jobs. Higher scores indicated greater levels of job resources.

Job resources represent characteristic of the job that allow employees to cope with demands and help them flourish in their jobs. To evaluate job resources, we employed the Psychosocial Factors Questionnaire (PSF-Q75), which was validated in Spanish by Madrid and colleagues (2020). From the range of available resources, we selected three to assess, specifically, task autonomy (three items), social support (six items), and significance (three items). Our aim in choosing these resources was to represent three distinct categories of job resources, namely, task resources (autonomy), social resources (social support), and job meaning (significance). The questionnaire employed a 5-point Likert scale, which asked participants to indicate the extent to which they agreed or disagreed with various statements about their jobs. Higher scores indicated greater levels of job resources.

Job resources represent characteristic of the job that allow employees to cope with demands and help them flourish in their jobs. To evaluate job resources, we employed the Psychosocial Factors Questionnaire (PSF-Q75), which was validated in Spanish by Madrid and colleagues (2020). From the range of available resources, we selected three to assess, specifically, task autonomy (three items), social support (six items), and significance (three items). Our aim in choosing these resources was to represent three distinct categories of job resources, namely, task resources (autonomy), social resources (social support), and job meaning (significance). The questionnaire employed a 5-point Likert scale, which asked participants to indicate the extent to which they agreed or disagreed with various statements about their jobs. Higher scores indicated greater levels of job resources.

Challenge demands are job-related obstacles that require effort to overcome and achieve good performance. Crucially, these demands are an inherent and essential aspect of the job. To evaluate challenge demands, we employed the Spanish version of the Job Characteristics Questionnaire, which was validated by Bayona and colleagues (2015). We specifically focused on three distinct challenge demands, namely workload (six items), job complexity (four items), and information processing requirements (five items). The questionnaire utilized a 5-point Likert scale, which asked participants to indicate the extent to which they agreed or disagreed with various statements about their jobs. Higher scores indicated greater levels of challenge demands. Sample items included "I have to work very quickly" for workload, "My job requires me to work on problems that have no clear solution" for job complexity, and "My job necessitates managing a large volume of information" for information processing.

Challenge demands are job-related obstacles that require effort to overcome and achieve good performance. Crucially, these demands are an inherent and essential aspect of the job. To evaluate challenge demands, we employed the Spanish version of the Job Characteristics Questionnaire, which was validated by Bayona and colleagues (2015). We specifically focused on three distinct challenge demands, namely workload (six items), job complexity (four items), and information processing requirements (five items). The questionnaire utilized a 5-point Likert scale, which asked participants to indicate the extent to which they agreed or disagreed with various statements about their jobs. Higher scores indicated greater levels of challenge demands. Sample items included "I have to work very quickly" for workload, "My job requires me to work on problems that have no clear solution" for job complexity, and "My job necessitates managing a large volume of information" for information processing.

Challenge demands are job-related obstacles that require effort to overcome and achieve good performance. Crucially, these demands are an inherent and essential aspect of the job. To evaluate challenge demands, we employed the Spanish version of the Job Characteristics Questionnaire, which was validated by Bayona and colleagues (2015). We specifically focused on three distinct challenge demands, namely workload (six items), job complexity (four items), and information processing requirements (five items). The questionnaire utilized a 5-point Likert scale, which asked participants to indicate the extent to which they agreed or disagreed with various statements about their jobs. Higher scores indicated greater levels of challenge demands. Sample items included "I have to work very quickly" for workload, "My job requires me to work on problems that have no clear solution" for job complexity, and "My job necessitates managing a large volume of information" for information processing.

Challenge demands are job-related obstacles that require effort to overcome and achieve good performance. Crucially, these demands are an inherent and essential aspect of the job. To evaluate challenge demands, we employed the Spanish version of the Job Characteristics Questionnaire, which was validated by Bayona and colleagues (2015). We specifically focused on three distinct challenge demands, namely workload (six items), job complexity (four items), and information processing requirements (five items). The questionnaire utilized a 5-point Likert scale, which asked participants to indicate the extent to which they agreed or disagreed with various statements about their jobs. Higher scores indicated greater levels of challenge demands. Sample items included "I have to work very quickly" for workload, "My job requires me to work on problems that have no clear solution" for job complexity, and "My job necessitates managing a large volume of information" for information processing.

Challenge demands are job-related obstacles that require effort to overcome and achieve good performance. Crucially, these demands are an inherent and essential aspect of the job. To evaluate challenge demands, we employed the Spanish version of the Job Characteristics Questionnaire, which was validated by Bayona and colleagues (2015). We specifically focused on three distinct challenge demands, namely workload (six items), job complexity (four items), and information processing requirements (five items). The questionnaire utilized a 5-point Likert scale, which asked participants to indicate the extent to which they agreed or disagreed with various statements about their jobs. Higher scores indicated greater levels of challenge demands. Sample items included "I have to work very quickly" for workload, "My job requires me to work on problems that have no clear solution" for job complexity, and "My job necessitates managing a large volume of information" for information processing.

Challenge demands are job-related obstacles that require effort to overcome and achieve good performance. Crucially, these demands are an inherent and essential aspect of the job. To evaluate challenge demands, we employed the Spanish version of the Job Characteristics Questionnaire, which was validated by Bayona and colleagues (2015). We specifically focused on three distinct challenge demands, namely workload (six items), job complexity (four items), and information processing requirements (five items). The questionnaire utilized a 5-point Likert scale, which asked participants to indicate the extent to which they agreed or disagreed with various statements about their jobs. Higher scores indicated greater levels of challenge demands. Sample items included "I have to work very quickly" for workload, "My job requires me to work on problems that have no clear solution" for job complexity, and "My job necessitates managing a large volume of information" for information processing.

Hindrance demands refer to job-related obstacles that hinder work performance. Unlike challenge demands, hindrance demands are usually not inherent to the job itself. To measure hindrance demands, we utilized the Questionnaire on the Experience and Assessment of Work, developed by Van Veldhoven and Meijman (1994). We selected three typical hindrance demands that workers encounter, namely interdependence (three items), emotional demands (five items), and role conflict (four items). The questionnaire employed a 5-point Likert scale that required participants to indicate the extent to which they agreed or disagreed with various statements related to their jobs. Higher scores represented greater levels of hindrance demands. Sample items included "I cannot finish my job until others complete theirs" for interdependence, "My job is often emotionally draining" for emotional demands, and "I am required to perform contradictory tasks at work" for role conflict.

Hindrance demands refer to job-related obstacles that hinder work performance. Unlike challenge demands, hindrance demands are usually not inherent to the job itself. To measure hindrance demands, we utilized the Questionnaire on the Experience and Assessment of Work, developed by Van Veldhoven and Meijman (1994). We selected three typical hindrance demands that workers encounter, namely interdependence (three items), emotional demands (five items), and role conflict (four items). The questionnaire employed a 5-point Likert scale that required participants to indicate the extent to which they agreed or disagreed with various statements related to their jobs. Higher scores represented greater levels of hindrance demands. Sample items included "I cannot finish my job until others complete theirs" for interdependence, "My job is often emotionally draining" for emotional demands, and "I am required to perform contradictory tasks at work" for role conflict.

Hindrance demands refer to job-related obstacles that hinder work performance. Unlike challenge demands, hindrance demands are usually not inherent to the job itself. To measure hindrance demands, we utilized the Questionnaire on the Experience and Assessment of Work, developed by Van Veldhoven and Meijman (1994). We selected three typical hindrance demands that workers encounter, namely interdependence (three items), emotional demands (five items), and role conflict (four items). The questionnaire employed a 5-point Likert scale that required participants to indicate the extent to which they agreed or disagreed with various statements related to their jobs. Higher scores represented greater levels of hindrance demands. Sample items included "I cannot finish my job until others complete theirs" for interdependence, "My job is often emotionally draining" for emotional demands, and "I am required to perform contradictory tasks at work" for role conflict.

Hindrance demands refer to job-related obstacles that hinder work performance. Unlike challenge demands, hindrance demands are usually not inherent to the job itself. To measure hindrance demands, we utilized the Questionnaire on the Experience and Assessment of Work, developed by Van Veldhoven and Meijman (1994). We selected three typical hindrance demands that workers encounter, namely interdependence (three items), emotional demands (five items), and role conflict (four items). The questionnaire employed a 5-point Likert scale that required participants to indicate the extent to which they agreed or disagreed with various statements related to their jobs. Higher scores represented greater levels of hindrance demands. Sample items included "I cannot finish my job until others complete theirs" for interdependence, "My job is often emotionally draining" for emotional demands, and "I am required to perform contradictory tasks at work" for role conflict.

Hindrance demands refer to job-related obstacles that hinder work performance. Unlike challenge demands, hindrance demands are usually not inherent to the job itself. To measure hindrance demands, we utilized the Questionnaire on the Experience and Assessment of Work, developed by Van Veldhoven and Meijman (1994). We selected three typical hindrance demands that workers encounter, namely interdependence (three items), emotional demands (five items), and role conflict (four items). The questionnaire employed a 5-point Likert scale that required participants to indicate the extent to which they agreed or disagreed with various statements related to their jobs. Higher scores represented greater levels of hindrance demands. Sample items included "I cannot finish my job until others complete theirs" for interdependence, "My job is often emotionally draining" for emotional demands, and "I am required to perform contradictory tasks at work" for role conflict.

Hindrance demands refer to job-related obstacles that hinder work performance. Unlike challenge demands, hindrance demands are usually not inherent to the job itself. To measure hindrance demands, we utilized the Questionnaire on the Experience and Assessment of Work, developed by Van Veldhoven and Meijman (1994). We selected three typical hindrance demands that workers encounter, namely interdependence (three items), emotional demands (five items), and role conflict (four items). The questionnaire employed a 5-point Likert scale that required participants to indicate the extent to which they agreed or disagreed with various statements related to their jobs. Higher scores represented greater levels of hindrance demands. Sample items included "I cannot finish my job until others complete theirs" for interdependence, "My job is often emotionally draining" for emotional demands, and "I am required to perform contradictory tasks at work" for role conflict.

Genomic DNA from fecal samples, with a focus on 16s ribosomal RNA. It will be measured only in a subgroup of 32 participants from both the intervention arm (n=16) and the active control arm (n=16).

Genomic DNA from fecal samples, with a focus on 16s ribosomal RNA. It will be measured only in a subgroup of 32 participants from both the intervention arm (n=16) and the active control arm (n=16).

Simultaneously, the synchronization between heart rate variability and respiratory rate will be studied, filtering both signals to eliminate artifacts. Respiratory sinus arrhythmias will be analyzed as an indirect indicator of vagal tone. It will be measured only in a subgroup of 32 participants from both the intervention arm (n=16) and the active control arm (n=16).

Simultaneously, the synchronization between heart rate variability and respiratory rate will be studied, filtering both signals to eliminate artifacts. Respiratory sinus arrhythmias will be analyzed as an indirect indicator of vagal tone. It will be measured only in a subgroup of 32 participants from both the intervention arm (n=16) and the active control arm (n=16).