The effect of a rhythmic pulse on the heart rate: Little evidence for rhythmical ‘entrainment’ and ‘synchronization’

In this study, we investigate the influence of musical tempo on the heart rate. Previous studies showed ambiguous results. Two effects are considered: first, an adaption of the heart rate frequency to the tempo of a musical stimulus (‘entrainment’) and second, the phase synchronization between the stimulus-onset and the R-waves in the ECG (‘synchronization’). A regulatory feedback loop was programmed, which constantly measured the actual heart rate. A simple Djembé-beat was used as a musical stimulus and coupled to the actual heart rate in real-time. To test for ‘entrainment’ effects, we adapted the tempo of the stimulus in real-time to the actual heart rate by increasing the rate 25%, 40% or 55% over the baseline tempo. To test for ‘synchronization’ effects, we presented the stimulus in a constant tempo, tracking the actual heart rate of the test person. Based on circular statistics, results showed no evidence for ‘entrainment’ or ‘synchronization’ effects of the stimulus on the heart rate. Overall, reactions to the trigger pulse were characterized by a high degree of interindividual differences. Thus, we conclude that there is no direct and simple correlation between the musical tempo and the HR contrary to what is often suggested in everyday psychology.