dagnattsyklusen

Dagnattsyklusen refers to the daily cycle of activity and rest observed in most living organisms, commonly known as the circadian rhythm. This internal biological clock regulates a variety of physiological processes, including sleep-wake patterns, hormone release, body temperature, and metabolism. The cycle is primarily influenced by external cues, most notably light and darkness, which signal to the brain to adjust the organism's behavior and internal functions accordingly.

In humans, the circadian rhythm is controlled by the suprachiasmatic nucleus (SCN) in the hypothalamus, a region of the brain that receives direct input from the eyes. As daylight fades, the SCN signals the pineal gland to produce melatonin, a hormone that promotes sleepiness. Conversely, when light enters the eyes in the morning, melatonin production is suppressed, leading to increased alertness. Disruptions to this natural cycle, such as from shift work, jet lag, or excessive exposure to artificial light at night, can lead to a range of health problems, including sleep disorders, mood disturbances, and increased risk of chronic diseases. Maintaining a regular sleep-wake schedule and exposing oneself to natural light during the day are key to supporting a healthy dagnattsyklus.