circadian

/sərˈkeɪdiən/
adjective
  1. Relating to the natural 24-hour cycle of physical, mental, and behavioral changes in living things, especially in response to light and darkness.
    • Your circadian rhythm helps you feel sleepy at night and awake during the day.
    • Exposure to bright light in the morning can help reset your circadian cycle.
    • Shift workers often struggle with their circadian clock because they sleep at unusual hours.
Synonyms
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