Figure 2
From: Cardiorespiratory optimization during improvised singing and toning
Cardiovascular data. Heart rate increases during vocal production, similarly for song singing and toning. Overall heart rate variability (SDNN) increases in all conditions relative to baseline, significantly more during toning compared to singing, and significantly more during silent breathing compared to the matched vocal conditions. For LF and HF heart rate variability see text. All conventions as in Fig. 1.
