There is described a method for evaluating a heart rate variability comprising: receiving an electrocardiogram representing an electrical activity of a heart； 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； for each per-frame modulation spectrogram, determining a respective central modulation frequency； 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.
