An experimental investigation of the effects of resonance frequency breathing on symptoms of anxiety

Background: Generalised anxiety disorder (GAD) is characterised by cognitive and physiological symptoms including uncontrollable worry, deficits in inhibitory control, and low heart rate variability (HRV). To date, the literature linking HRV and cognitive processes relevant to GAD is predominantly correlational. We present an experiment designed to examine the causal relationship between increased HRV and inhibitory control. Methods: Participants (N = 133, 81.3% identifying as female, age range 18 – 37, Mean age = 24.21, SD = 4.54) with high levels of trait anxiety (GAD7 questionnaire ≥ 10) and worry (Penn State Worry Questionnaire ≥62) were randomised to an experimental or active control condition. Participants completed baseline assessments of mood state, respiration rate, HRV, and inhibitory control. The experimental group completed a resonance frequency breathing (RFB) assessment to determine the breathing rate at which HRV is maximised. The active control group underwent a sham breathing assessment and manipulation. The experimental group then completed a period of RFB and the control group breathed at their baseline mean rate. Participants repeated the inhibitory control assessment. Results: We present preliminary data analyses on the efficacy of the respiration manipulation and its effect on HRV and measures of inhibitory control. The HRV manipulation was successful with the experimental group showing significantly higher low frequency power during RFB than the control group (p = < 0.001). Examining the RMSSD HRV metric, there was a significant time (time 1 baseline vs. time 2 during breathing manipulation) x group (experimental vs. control) interaction (p = 0.04) showing HRV to be higher at time 2 during the breathing manipulation in the experimental group as compared to the control condition. There was no significant time x group interaction effect of HRV increase on inhibitory control, p = .93. Discussion: We discuss the application of the experimental design to examine the effect of respiration manipulation on HRV and inhibitory control in the context of anxiety. Future directions for this research will be discussed.