vuorokausirytminä

Vuorokausirytmi, also known as the circadian rhythm, refers to the biological processes that operate on a roughly 24-hour cycle. These internal clocks influence a wide range of physiological and behavioral functions in living organisms, including humans. The most well-known manifestation of the circadian rhythm is the sleep-wake cycle, which dictates when we feel tired and when we feel alert.

The master clock regulating these rhythms is located in the suprachiasmatic nucleus (SCN) of the hypothalamus in the brain. This central pacemaker is synchronized primarily by light cues from the environment. When light enters the eyes, it signals the SCN, which then coordinates the body's internal timing. Darkness, conversely, promotes the release of melatonin, a hormone that signals the body to prepare for sleep.

Beyond sleep, circadian rhythms affect hormone secretion, body temperature, metabolism, and cellular repair. Disruptions to these rhythms, such as those caused by shift work, jet lag, or irregular sleep patterns, can have negative health consequences, including increased risk of mood disorders, metabolic issues, and impaired cognitive function. Maintaining a consistent daily routine and adequate exposure to natural light are crucial for supporting healthy circadian function. The study of these biological rhythms is known as chronobiology.