Circadian rhythm is the natural, internal process that regulates the sleep-wake cycle and other physiological functions in living organisms. It typically follows a roughly 24-hour cycle, responding to environmental cues like light and temperature. This rhythm helps determine sleep patterns, feeding habits, hormone release, and other bodily functions. In humans, circadian rhythms are influenced by the suprachiasmatic nucleus, a group of cells in the brain that responds to light signals. Disruptions to this rhythm, such as those caused by shift work or irregular sleep patterns, can lead to various health issues, including sleep disorders and metabolic problems.