HRV Biofeedback Training Decreases Beck Depression Inventory Scores in Healthy Students

This randomized controlled study explored whether HRV biofeedback training can decrease the Beck Depression Inventory (BDI) scores of students with low self-reported levels of depression. Twenty-one undergraduates (7 male and 14 female), 18-22 years of age, participated in this study. A Thought Technology ProComp[TM] Infiniti system was used to monitor ECG, HRV, respiration, SCL, and temperature. In this mixed-design study, subjects were pre-assessed on both the Beck Depression Inventory (BDI) and State-Trait Anxiety Inventory, matched on State Anxiety scores, randomly assigned to four sessions of either HRV or temperature biofeedback, and then post-assessed on both inventories. Each weekly training session consisted of stabilization (5 min), pre-baseline (5 min), biofeedback training (30 min), and post-baseline (5 min) conditions. The HRV biofeedback group (HRV) was instructed to sit upright, breathe six times per minute, and increase peak-to-trough heart rate differences. They received visual analog respirometer and heart rate feedback, and practiced breathing six times per minute for 15 min a day. The temperature biofeedback group (TEMP) was instructed to sit upright and increase index finger temperature. They received visual analog temperature feedback and practiced hand-warming for 15 min a day. Compliance was confirmed by weekly logs. Data were analyzed using a GLM analysis with familywise correction. Both biofeedback groups succeeded in learning self-regulation of their modality. The HRV group increased the SDNN (standard deviation of all NN intervals) from session 1 (69.3 ms) to session 4 (93.8 ms), F(1,11) = 12.81, p = .004, [[eta].sup.2] = 0.54. The TEMP group increased hand temperature from session 1 (88.8 degrees F) to session 4 (92.2 degrees F), F(1,10) = 6.54, p = .028, [[eta].sup.2] = 0.40. The HRV group reduced BDI scores from pre-assessment to post-assessment over a 6-week period, F(1,10) = 6.37, p = .03, [[eta].sup.2] = 0.39, while TEMP group's BDI scores did not change. Moreover, the HRV group achieved lower post-assessment BDI scores than the TEMP group, F(2,23) = 11.80, p = 0.000, [[eta].sup.2] = 0.51. Future replications should study a genderbalanced sample of students diagnosed with depression. Keywords * Heart rate variability biofeedback * Temperature biofeedback * Beck depression inventory * State-trait anxiety