Sleep-wake cycles refer to the natural pattern of alternating between periods of wakefulness and sleep. These cycles are regulated by various physiological processes, including hormone production.
A hormone secreted by the pineal gland that helps regulate sleep-wake cycles. It increases in darkness and decreases with exposure to light.
REM Sleep (Rapid Eye Movement): A stage of sleep characterized by rapid eye movements, vivid dreaming, and muscle paralysis. It is an important part of the sleep-wake cycle.