Circadian rhythms begin to develop in infancy. Newborns typically do not have a well-established circadian rhythm, which is why they often sleep and wake at irregular intervals. By around 3 to 4 months of age, most infants start to develop a more regular sleep-wake pattern. By the age of 6 months, many infants exhibit clear circadian rhythms, influenced by external cues such as light exposure and social interactions.
