Table 4.

The different rhythm categories and the corresponding rhythm metrics.

Periodicity	Rhythm Metrics
Ultradian	Multi-scale entropy, power spectrum density (with period less than 20 h)
Circadian	M10, L5, relative amplitude, deviation from template, interday stability, intraday variability, power spectrum density (with period greater than 20 h and less than 30 h)
Infradian	Power spectrum density (with period greater than 30 h)

The categorization, namely ultradian, circadian, and infradian, is based on whether the rhythm’s periodicity is less than, equal to, or greater than 24 h.