Mild cognitive impairment (MCI) individuals also show significant parasympathetic deficits, while autonomic nervous system (ANS) flexibility can strengthen cognitive and brain function. Paced (or slow) breathing has significant effects on the ANS and is associated with relaxation and well-being. However, paced breathing requires considerable time and practice, a significant barrier to its widespread adoption. Feedback systems appear promising to make practice more time-efficient. A tablet guidance system providing real-time feedback on autonomic function was developed for MCI individuals and tested for efficacy. In this single-blind study, 14 outpatients with MCI practised with the device for 5min twice a day for 2 weeks. The active group received feedback (FB+), whereas the placebo group (FB-) did not. Coefficient of variation of R-R intervals as the outcome indicator was measured immediately after the first intervention (T1 ), the end of the 2-week intervention (T2 ), and 2 weeks later (T3 ). The mean outcome of the FB- group remained unchanged during the study period, whereas the outcome value of the FB+ group increased and retained the intervention effect for an additional 2 weeks. Results indicate this FB system-integrated apparatus may be useful for MCI patients for effectively learning paced breathing.