rhythm-, rhythmo- +

(Greek: regularly recurring motion; measured motion)

biological rhythm
The study of the effect of time on biological events, especially repetitive or cyclic phenomena in individuals.
biorhythm, biorhythms
1. Supposed regular cycles in human physiological processes that affect emotions and behavior.
2. A biologically inherent cyclic variation or recurrence of an event or state; such as, the sleep cycle, circadian rhythms, or periodic diseases.
3. An endogenous cyclic variation in some aspect of an organism's bodily functioning, as the daily cycle of sleeping and waking, or the annual cycle of dormancy and activity in some animals; specifically each of three alleged cycles of different periods involving a person’s physical, emotional, and intellectual activity, as used to explain or predict behavior.
biorhythmicist
Someone who advocates or employs biorhythmics or the study of biorhythms (an innate periodicity in an organism's physiological processes; such as, sleep and wake cycles).
bradyarrhythmia
Any disturbance in the heart rhythm in which the ventricular-heart rate is abnormally slowed, usually to less than 60 beats per minute in an adult.
bradydysrhythmia, bradyarrhythmia (s) (noun); bradydysrhythmias, bradyarrhythmias (pl)
A disturbance of the heart beat, typically fewer than 60 beats per minute in the average adult: "The doctor used his stethoscope to listen to the bradydysrhythmia of the patient and then he decided to refer her to a cardiologist for a more exact examination and diagnosis."
bradyrhythmia
Slowness of the heartbeat, as evidenced by slowing of the pulse rate to less than 60 beats per minute in an adult.
cacorhythmic (adjective), more cacorhythmic, most cacorhythmic
In bad rhythm; also formerly applied to an irregular or disorderly pulse.
circadian rhythm
The regular recurrence, in cycles of about 24 hours, of biological processes or activities; such as, sensitivity to drugs and stimuli, hormone secretion, sleeping, feeding, etc.

This rhythm seems to be set by a "biological clock" which seems to be set by recurring daylight and darkness.

delta rhythm
A pattern of slow brain waves, having a frequency of less than six cycles per second as recorded by an electroencephalograph, associated with deep sleep.
dysrhythmia
1. An irregularity in an otherwise normal rhythm, especially of heartbeats or brainwaves.
2. Abnormal, disordered, or disturbed rhythm.
3. An abnormality in an otherwise normal rhythmic pattern, as of brain waves being recorded by an electroencephalograph.
endogenous rhythm
An innate internal activity cycle of an organism that appears to be initially mediated by such exogenous factors as the length of day and season but that persists in the absence of external stimuli.
eurhythmia
Harmonious relationships in the body or separate organ development.
eurhythmic
1. Characterized by a pleasing rhythm.
2. Harmoniously ordered or proportioned.
eurhythmics, eurythmics
1. The art of interpreting musical compositions by rhythmical, free-style bodily movement.
2. The art of interpreting in bodily movements the rhythm of musical compositions.

Applied to a method invented by Emile Jaques-Dalcroze, a Swiss composer, with the purpose of developing the sense of rhythm and symmetry.

exogenous rhythm
An activity response to a rhythmic external environmental stimulus; such as, a photoperiodic response by an organism to the length of the day.