Date of Graduation


Document Type


Degree Type



Eberly College of Arts and Sciences



Committee Chair

Kevin T. Larkin

Committee Co-Chair

Amy Gentzler

Committee Member

Lisa Kimmerer

Committee Member

Tracy Morris

Committee Member

Susannah Poe


The current study was designed to examine the efficacy of heart rate variability (HRV) biofeedback using emWave, a specific biofeedback device available to the public, and to determine whether such treatment affects phasic physiological responses to stress. Twenty-seven individuals (4 males, 23 females), aged 18-30 years (M = 22.54 years, SD = 3.82) participated in the current study. Thirteen individuals were randomly assigned to a control group and received no intervention, whereas the remaining 14 participants underwent 4-8 sessions of emWave intervention. All participants attended pre-treatment and post-treatment assessment sessions during which a stressor protocol was administered; physiological data were collected during rest, during stress, and following stress. EmWave treatment did not confer changes in resting, or tonic, measures of HRV. However, participants who received emWave treatment exhibited higher parasympathetic responses (i.e., pNN50) during stress at the post-treatment session compared to their control counterparts. Significant group differences in HRV were not evident during the post-stress recovery period. Additionally, no treatment effects were evident on self-reported measures of stress, psychological symptoms, or affect administered during the pre- and post-treatment assessment visits. Overall, results from the current study, combined with previous literature, suggest that the emWave may confer some limited treatment effects by increasing HRV in response to stress. Additional development and testing of the emWave treatment protocol is necessary before it can be recommended for regular use in clinical settings, including the determination of what physiological changes occur during HRV biofeedback that contribute to any clinical effects that may occur with the emWave treatment.