Stress-related disorders have over the last decade increased and contributed to a worldwide disease burden. At the same time there is limited treatment access for mental health disorders, which has left many people without necessary care. However, in recent years there has been a rise in digital mindfulness interventions. Specifically, these interventions have focused on smartphone-based applications as an effective format for mindfulness training programs. Thus, the goal of this randomized controlled trial is to test the effects of three types of mindfulness programs in a population with elevated stress. The three formats of mindfulness interventions are identical in total training duration but varies in content and intervention length. Specifically, the first intervention consists of programmatic mindfulness content that progress over the course of 30 sessions with a duration of 10 min per session. The second intervention consists of single succinct breathing exercises with no programmatic content over the course of 30 sessions with a duration of 10 min per session. The third intervention consists of mindfulness-based content specifically targeted to people with elevated stress that progress over the course of 20 sessions with a duration of 15 min per session. An active control group listening to an audiobook over the course of 30 sessions with a duration of 10 min per session will be employed and a passive control group.

The study will evaluate outcomes related to subjective stress, sleep quality, mindfulness and physiological effects of stress using HRV.

Inclusion Criteria:

• Moderate to high perceived stress based on PSS total scores (14-40)
• Fluent in English

Exclusion Criteria:

• Regular mindfulness practice for more than 1 month within the last year
• Medical diagnosis e.g. psychiatric/neurological conditions
• Low levels of stress (i.e., less than a score of 14 assessed with the PSS)