Sömndrivenhet

Sömndrivenhet, often translated as sleep-drive or somnolence, refers to the physiological urge to sleep. It is a fundamental biological need that plays a crucial role in maintaining overall health and cognitive function. This drive is influenced by two primary processes: the homeostatic sleep drive and the circadian rhythm.

The homeostatic sleep drive, also known as sleep pressure, builds up the longer an individual remains awake. Adenosine, a byproduct of cellular activity, accumulates in the brain throughout the day, promoting a feeling of sleepiness. As adenosine levels increase, so does the intensity of the urge to sleep. This pressure is then relieved by sleep itself, with adenosine levels decreasing during rest.

The circadian rhythm, a roughly 24-hour internal biological clock, also regulates sleep-wake patterns. This internal clock is influenced by external cues, primarily light, and dictates periods of wakefulness and sleepiness throughout the day and night. While the homeostatic drive signals the need for sleep based on duration of wakefulness, the circadian rhythm dictates the optimal timing for sleep. The interplay between these two systems ensures that we experience periods of alertness and periods of somnolence, facilitating restorative sleep. Disruptions to either the homeostatic drive or the circadian rhythm can lead to sleep disturbances and daytime sleepiness.