Conclusions

These findings indicate that a single session of slow breathing, regardless of biofeedback, is sufficient for controlling physiological arousal in anticipation of psychosocial stress associated with music performance and that slow breathing is particularly helpful for musicians with high levels of anxiety. Future research is needed to further examine the effects of HRV BF as a low-cost, non-pharmacological treatment for music performance anxiety.

Heart rate variability biofeedback (HRV BF) is an intervention involving slow breathing (6 breathes per minute), which dampens physiological arousal in stressful situations[17]. It has been associated with reductions in anxiety symptoms [18], [19] and improved cognitive performance [20]. Heart Rate Variability (HRV) is an index of beat to beat changes in heart rate and is a psychophysiological marker for physical and mental health [21]–[23]. Low HRV is associated with mood and anxiety disorders[24]–[27]. High HRV has a protective effect and is associated with good health [28] and well-being [29].

High frequency (HF) HRV reflects the magnitude of PNS influence on HR associated with breathing – respiratory sinus arrhythmia (RSA) [30] – which is carried to the heart via the tenth cranial (vagus) nerve. Power spectral analysis partitions the observed variability into components of high (HF), low (LF) and very low frequency (VLF) using spectral decomposition, most commonly a Fast Fourier Transformation [30]. PNS, sympathetic nervous system (SNS) and blood pressure mechanisms operate on different time scales, so each of these components is thought to be associated with different sources of variability [31]. The HF component (between 0.15–0.4 Hz) is known to be PNS mediated [32]–[34], while the LF component (0.04–0.15 Hz) reflects a combination of PNS and SNS activity [35] via baroreflex function [31]. As a consequence, the LF/HF ratio is thought to provide information about the relationship of vagal input to the other sources of variability [36].

Higher levels of resting state HF HRV may indicate increased ability to inhibit SNS-mediated arousal [37], leading to increased behavioural flexibility [38] in the face of stress and reduced anxiety, as argued by Thayer and colleagues [39]–[41]. Maladaptive emotion regulation strategies, such as worry, lead to acute reductions in HRV [25]whereas social approach behaviors are associated with increased parasympathetic activity, which is facilitated by an increase in vagal tone [42].

The aim of HRV BF is to slow the breathing (normally ~15 breaths per minute) to coincide with HRV changes due to the baroreflex (~6 cycles per minute, or 0.1 hz) resulting in what is known as resonant frequency [55], resulting in a large multiplicative increase in the amplitude of HR oscillations and HRV power. Each individual has a resonant frequency [49] usually achieved at around 6 breaths per minute [51]. HRV BF involves training in abdominal breathing techniques, establishment of resonant frequency and monitoring over 10 weeks with home practice [55]. It has been linked to improvements in PTSD symptoms [18], [19], depression [56]–[59], state anxiety [56],[60], cardiovascular disease 17,61,62 and HRV levels [17], [19], [56], [60].

Participants who received slow breathing exhibited greater increases in HF and decreases in LF/HF ratio than controls after intervention, indicating increased levels of parasympathetic influence on HR while under stress. This increased level of PNS inhibition may allow participants to better regulate physiological arousal prior to music performance and to perform more competently. Amongst highly anxious individuals, the intervention also led to greater reductions in self-reported anxiety than controls, indicating that slow breathing may have clinically-relevant effects for performing musicians who suffer from anxiety.

LF/HF ratio indicates the amount of HRV that is due to a combination of SNS, PNS and blood pressure mechanisms (LF) relative to vagal input (HF) under normal conditions. It should be noted that LF levels are also inflated by slow breathing, especially when breathing at a rate of 0.1 Hz, which is in the LF range. Breathing at this rate creates a resonant effect whereby oscillations of vagal outflow are timed to coincide with those in baroreflex action, producing large increases in the amplitude of HR changes [55]. 

In summary, the results of the present study indicate that diaphragmatic breathing instruction and a single session of slow breathing are sufficient to produce HRV increases and state anxiety reductions among musicians with high state anxiety, and that biofeedback is not necessary for these changes to occur. This suggests that integration of slow breathing with more comprehensive psychotherapy strategies may have clinical utility in the treatment of individuals with MPA. Slow breathing may be a viable alternative to beta-blockers for inhibition of SNS activity during performance.