Previous research suggests that musical tempo modulates listeners’ cardiovascular activity. Cardiovascular activity during music listening and performance has primarily been analysed using static linear measures of heart rate variability which cannot capture changes in cardiac activity over time. The nonlinear dynamics of cardiac activity during musical activities have yet to be studied systematically. We report an investigation of musicians’ melody performances measured over a 12-hour day and subsequent changes in the musicians’ cardiac activity. Skilled pianists completed four testing sessions in a single day (09h, 13h, 17h, 21h). Cardiac activity was recorded during an initial five minutes of baseline rest and during performances of familiar and unfamiliar melodies. We applied Recurrence Quantification Analysis to capture the nonlinear cardiac dynamics during baseline rest and during music performances. Results indicated that cardiac dynamics were more predictable and changed more slowly during music performance than baseline rest. During performances of unfamiliar melodies than familiar melodies, cardiac dynamics changed more slowly. The differences in cardiac dynamics between conditions were most evident at earlier testing times. These findings provide the first evidence of cardiac dynamics that are unique to music performance contexts.