Circadian Rhythm
Within the circadian (24-hour) cycle, a person usually sleeps approximately 8 hours and is awake 16. During the wakeful hours, mental and physical functions are most active and tissue cell growth increases.
Information sourced from Britannica
Ultradian rhythms are biological cycles occurring within 24 hours, like a heart rate that lasts less than a second (although it repeats in a loop).
Information sourced from Science Direct