Circadian Science

The circadian rhythm is a biological process governed by an internal timing mechanism that operates on an approximately 24-hour cycle. These rhythms influence sleep patterns, hormone release, appetite, digestion, and temperature regulation. The human circadian clock synchronizes with the natural day-night cycle, using sunlight as its primary cue, and resets each morning with exposure to sunrise. In 2017, the Nobel Prize was awarded for the discovery of the molecular mechanisms that control circadian rhythms.

• Sunlight is the primary regulator of our internal clock. The eye serves as the sole pathway for light information, projecting directly to the master pacemaker located in the hypothalamus (Reference 700).

• The human circadian clock synchronizes with sunlight. Our biological clock, which governs everything from gene expression to behavior, aligns with the Earth’s 24-hour rotation through environmental cues known as zeitgebers. This active alignment process is called entrainment (Reference 701).

• Improving your well-being starts with restoring your circadian rhythms, the internal mechanisms that synchronize your biological processes with the natural cycle of day and night (Reference 118).

• Nearly all organisms have evolved internal clocks that coordinate physiological processes, ensuring that distinct functions take place at specific times throughout the day. This adaptation allows organisms to synchronize their behavior and biology with the daily cycle of light and darkness (Reference 550).

• Because our environment is shaped by the Earth's rotation, it is natural that organisms have adapted by developing circadian rhythms that regulate physiological and behavioral activities throughout the day (Reference 551)