All physiologic functions demonstrate cyclic activity. Infant developm
ent includes maturation of biorhythms. Two basic changes in biorhythm
include establishment of circadian rhythm and day-night pattern. Biorh
ythms are driven by internal pacemakers yet are highly susceptible to
environmental influences, Sleep-wake pattern and body temperature rhyt
hm are two examples of infant biorhythms that demonstrate significant
change with development; Biorhythm is the scientific basis for interve
ntions (such as cycled lighting, feeding schedule, and caregiving patt
ern) aimed at improving the fit between infant and the environment.