Sleep is one of the body’s most important biological processes. This section explains some of the key terms involved in sleep, recovery, restoration, and the rhythms that help regulate daily life. Adenosine Adenosine is a chemical compound that builds up in the brain during waking hours and contributes to the feeling of sleepiness. As adenosine levels increase, the drive to sleep becomes stronger. Sleep helps clear accumulated adenosine, supporting the next cycle of wakefulness. Related: Body Clock The body clock is the internal timing system that helps regulate daily rhythms. It influences sleep, wakefulness, hormone release, body temperature, and other…