Method and system for determining heart rate variability

A system for evaluating a heart rate variability, comprising:

• a spectrum calculator for receiving an electrocardiogram representing an electrical activity of a heart and determining a modulation spectrum for the electrocardiogram, the modulation spectrum comprising a plurality of per-frame modulation spectrograms each representing a frequency as a function of a modulation frequency;
• a central frequency calculating unit for determining, for each per-frame modulation spectrogram, a respective central modulation frequency;
• and
• a heart rate variability determining unit for determining an indication of the heart rate variability using the determined respective central modulation frequencies for the per-frame modulation spectrograms, a mean central modulation frequency and the number of per-frame modulation spectrograms and outputting the indication of the heart rate variability.