Mindfulness, the awareness emerging through paying attention purposefully, nonjudgmentally, to the unfolding of experience moment by moment, can be cultivated through meditation. Several meta-analyses showed that mindfulness meditation improves cognition and reduces stress. Furthermore, the relationship between positive effects of meditation on cognition might be mediated by stress reduction. We adapted a paradigm originally used in action video game research in a cross-sectional design, comparing regular meditators and non-meditators in a working memory task. We examined learning abilities as initial performance and learning rate in the working memory task. Cardiac activity was recorded during the task as a biomarker of stress. Our results showed a difference in initial performance in the working memory task in favor of regular meditators and no significant difference in learning rate. However, there might be a tendency for greater learning rate in non-meditators. We found no difference in cardiac activity nor correlation with learning abilities.