circadische

Circadian rhythms are natural, internal processes that regulate the sleep-wake cycle and repeat roughly every 24 hours. These biological rhythms influence various physiological functions, including hormone release, body temperature, and metabolism. The term "circadian" originates from the Latin words *circa* (meaning "around") and *dies* (meaning "day"), reflecting their alignment with the Earth's rotation.

The primary regulator of circadian rhythms is the suprachiasmatic nucleus (SCN), a cluster of cells located in the hypothalamus of the brain. The SCN receives light signals from the retina, adjusting the body’s internal clock to match environmental light-dark cycles. Disruptions to this system, such as irregular sleep schedules or exposure to artificial light at night, can lead to misalignment between internal rhythms and external time cues, a condition known as circadian misalignment.

Circadian rhythms affect nearly every aspect of human health, including cognitive performance, immune function, and susceptibility to diseases like diabetes and depression. Shift workers, travelers crossing time zones, and individuals with sleep disorders often experience circadian desynchronization, which can impair well-being. To maintain healthy circadian rhythms, experts recommend consistent sleep schedules, exposure to natural light during the day, and minimizing screen time before bedtime.

Research into circadian biology continues to expand, with applications in medicine, agriculture, and even space exploration. Understanding these rhythms helps optimize productivity, health, and overall quality of life by aligning daily routines with the body’s natural cycles.