The term "circadian rhythm" refers to a natural cycle that occurs in living organisms, which is roughly 24 hours long. This cycle can be seen in various aspects of an organism's biology, such as its metabolism, hormone production, and sleep-wake cycles. The word "circadian" comes from the Latin words for "around" (circa) and "day" (diem), indicating that these rhythms have a cycle that is roughly aligned with the daily cycle of light and darkness in the environment. In humans, circadian rhythms are important for maintaining healthy sleep patterns, regulating metabolism, and controlling hormone production. Disruptions to these natural cycles can lead to various health problems, including sleep disorders and mood disturbances.