This version of the intervention prompted users to engage in social support which is thought to buffer against the negative effects of stress. This effect is present in occupational settings, with several studies indicating that social support plays an important role in preventing burnout among nurses. Furthermore, interventions targeting social support in the workplace suggest that these have positive effects on mental health. Sample strategies included asking for help from co-workers, listening with compassion, and sharing authentic emotions.

This version of the interventions promoted an increase of physical activity in daily life. Physical activity is well-known to improve various health outcomes similar to our outcomes of interest, for instance reducing stress and burnout symptoms. Additionally, physical activity interventions in the workplace are widely used and have been found effective in many studies. Sample strategies included taking walks, going to the gym, and using the stairs instead of the elevator.

This version of the intervention promoted a variety of psychological strategies for stress reduction. Sample strategies included sleep quality improvement tips, mindfulness, and work detachment - evidence-based strategies that have a positive effect on outcomes of interest. Workplace interventions targeting these kinds of strategies have been found to be effective.

Daily Intervention for Active Recovery - DIARY - is a 28-day intervention during which participants are prompted once daily to engage with intervention content. Each daily intervention interaction includes a short questionnaire with questions regarding sleep quality, current mood (e.g., tense, relaxed), and energy levels. Participants were prompted to open the application through a notification at 18:00 each evening. In case they did not fill out the questionnaire, an additional reminder notification was sent out at 20:00. The questionnaire closed each night at 03:00 am, at which point it was no longer possible to access the questionnaire for that day. The questionnaire took at most 5 minutes to complete. Upon completing the daily questionnaire participants received a prompt - a "bit-size" amount of information regarding stress and recovery as well as suggestions for a specific recovery strategy.

Adherence was operationalized as a count variable coded 0-28 representing the number of days that a given participant used the intervention.

App Engagement was measured using The App Engagement Scale, a 7-item questionnaire designed to measure engagement with mobile applications, translated into Swedish by the research team. This translation has been used previously by the research team and has preliminary evidence of good reliability. Items (e.g. "I enjoyed using the app") are scored on a 1-5 ordered categories scale (1 = Not at all, 5 = Fully agree).

Stress was measured daily as the mean value of three items inspired by the Stress-Energy Questionnaire. This study used a Swedish translation which has been validated in a previous study by the research team. Items ("During the last day, to what extent have you felt tense / pressed / frustrated?") were rated on a 6-point ordered categories scale (1 = Not at all, 6 = Very much). This variable was measured daily during the intervention and was not included in the pre-, post-, and follow-up measures.

Acceptability was measured using a set of single-item measures evaluating whether the intervention was relevant to the user, if they would like to use it again, quality of the prompts, and technical stability. These items were only included in the post-intervention measure.

Anxiety was measured using the GAD-7 questionnaire, a 7-item instrument designed to assess generalized anxiety disorder. This study uses a Swedish translation. Items (e.g. "Feeling nervous, anxious, or on edge") were scored on a 1-4 ordered categories scale (1 = Not at all, 4 = Nearly every day).