Objectives <p>Despite its benefits, maintaining positive affect during high-intensity exercise (HIE) can be challenging, impacting the likelihood of future physical activity. We addressed this challenge by exploring if training interoceptive awareness could improve affective responses during HIE. To ensure scalability, we utilized mindfulness training (MT) digital therapeutics (DTx), which have been previously demonstrated to increase stress resilience and attentional control.</p> Methods <p>Seventy undergraduate students (<i>M</i> = 26.5, <i>SD</i> = 10.3&#xa0;years old; 58.5% female) were randomly assigned to a 3-week DTx MT intervention (<i>n</i> = 35) or cognitive training (CT) (<i>n</i> = 35) as an active control. Baseline assessments of psychological (i.e. wellbeing, distress tolerance, effort, awareness, and attitude), physiological (i.e. heart rate and time to voluntary exhaustion), and behavioural (i.e. maximal athletic performance on a stationary bike) measures were taken and compared to the same measures at post-intervention using linear mixed model analyses.</p> Results <p>Preregistered analyses showed that DTx MT significantly enhanced interoceptive awareness compared to CT. HIE performance showed a small but significant advantage (<i>β</i> = .21) from DTx MT, and changes in performance were significantly related to improvements in both interoception and distress tolerance. Exploratory factor analysis revealed a substantial improvement in perceived effort and distress tolerance during HIE.</p> Conclusions <p>DTx MT appears to improve both body awareness and tolerance to physical distress in HIE. Such changes may lead to improvements in HIE performance; however, further research is needed. This study supports the benefits of DTx MT in exercise engagement and guides future research in the realm of performance enhancement.</p> Preregistration <p>This study was preregistered through the Open Science Framework (<a href="https://osf.io/57rct/">https://osf.io/57rct/</a>).</p>