Physical exercise and time of day: influences on spontaneous motor tempo

To identify whether spontaneous motor rhythm is influenced by external or internal events and whether this rhythm fluctuates across the day in parallel with heart rate diurnal variations, we simultaneously recorded heart rate and spontaneous motor rate before and after a pedaling task performed five times a day by 10 healthy human subjects. Each subject performed a Spontaneous Motor Tempo, i.e., a finger-tapping task, at a comfortable and spontaneous cadence. Pre- and postexercise Spontaneous Motor Tempo was measured as well as heart rate. There were diurnal variations in Spontaneous Motor Tempo. Both measures increased significantly after pedaling, suggesting that cardiac and spontaneous rhythms are influenced simultaneously after a moderate exercise. Also, finger-taps occurred most frequently around the initiation of the heart systole. These results suggest that a putative internal clock might regulate Spontaneous Motor Tempo and that cardiac rhythm might influence this tempo.