The present study sought to further understanding the acute impact of hard performance requirements (i.e., larger TD) on the autonomic and cardiovascular health of the wind musicians. As the main finding, our study points out that despite fatigue, musicians displayed larger parasympathetic responses in the hardest wind instrument performance after half an hour of playing. As expected, HR (RRi) was sensible to neuromuscular requirements while playing (i.e. Per1 and Per2) whatever the TD, coming back to lower values (i.e. higher RRi) in the recovery period with no intergroup differences. Unexpectedly, HRV vagal indices, including lnRMSSD, lnSD1, and SD2 (short- and long-term variability respectively), were larger, the higher the TD (i.e., in Per2). Moreover, SD2 and SD1/SD2 were affected only in the hardest piece, improving with Time-Course. According to these results, the higher the TD (i.e. higher perceived difficulty, physical exertion, and psychological effort), the better the autonomic modulation, confirming the acute beneficial effects of playing wind instruments.
In order to sound a wind instrument, musicians change their usual breathing, with each musical score demanding exactly where and how to breathe during the performance. Overall, we observed that vagal control diminished in the first lap, where musicians may be coping with rate dynamics to these continuous changes in breathing, but this initial discomfort may cause the autonomic reactivation that follows in Per2. The thrust of the diaphragmatic musculature in the expiration activates the vagus nerve endings (
11,
15) what would explain this parasympathetic reactivation. In addition, the polyvagal theory (
16) describes that during the expiration, there is an increase of the vagal excitation towards the Sino-atrial nodule. The longest duration of breathing can be associated with the greater amplitude of the Respiratory Sinus Arrhythmia, thus with better values of HRV. This can be interpreted as the improvement in the coordination between breathing and cardiovascular function (reflected in the RSA). In this sense, the rehearsal perceived as the hardest one had more difficult technical passages and more lively tempos (more than acute notes) that might have required greater depth in breathing. Given that it is proved that slow and deep breaths increase HRV (
17), playing more demanding musical pieces might be a more beneficial activity for the autonomic health, resulting in higher requirements for breathing and neural coupling.
Despite fatigue, enhanced acute autonomic cardiac responses when coping with more demanding performances in our study (i.e., increased vagal indexes with no differences in sympathetic arousal) support the idea of better pulmonary and cardiac synchronic coupling (
4,
17) in response to highly demanding performances in healthy professionals. Similar to the exercise, regular practice and higher intensities might indeed augment the somatosensory nerve traffic in the brainstem (
8), increasing its cardio-protector benefits. Although some studies (
1) previously showed that playing wind instruments increased HR in professional musicians, others (
5) already highlighted that HRV was able to detect changes in response to subtle manipulations neglected by HR dynamics. That is the vagal reactivation in the hardest TD in our study parallel to the increase in HR.
Since it has been suggested that continuing to play music during the aging process can be physically sustaining and cognitively beneficial, if the musician also pays adequate attention to technique, training schedules, and physical conditioning to avoid overload from other causes (
18), playing wind instruments becomes largely recommendable in terms of quality of life through the lifespan. Based on the assumption of the cardiac autonomic modulation as reflecting psychophysiological health (
5), HRV would be useful to monitor autonomic fatigue and help musicians to periodize the alternation of high demanding music training or performing, with short periods of rest or light training looking for autonomic recovery, similar to sports training periodization (
19).
5.1. Conclusions
In conclusion, playing wind instruments is established to be healthy in terms of autonomic modulation and cardiovascular functioning, and HRV is also confirmed to be useful in this field. However, it is important to point out that we had a very small sample, and we analyzed only acute responses, which is a limitation of our study. Our conclusions might be also limited because we had different instruments and pieces of music and the fact that participants had different academic levels and may have influenced the perception of the TD, thereby becoming a potential source of bias. Future studies with larger heterogeneous samples and direct measures of the breathing and cardiac neural coupling will help better understanding of these cardio-protection relationships, so we recommend that other authors should do this work with larger and specifier sample sizes.