Biological Rhythms

noun A genetically programmed internal timing device that regulates various physiological processes in an organism

• The biological clock regulates our sleep-wake cycle based on the natural circadian rhythm.
• I always wake up early because my biological clock is set that way.
• My biological clock is totally messed up from staying up late every night.
• As I get older, my biological clock seems to be ticking louder and louder.

verb moving or swinging back and forth in a regular rhythm

adjective having a back-and-forth motion

• The pendulum was oscillating back and forth with perfect precision.
• The fan in my room keeps oscillating and it's driving me crazy.
• I can't stand the way he keeps oscillating between different opinions.
• Her emotions were oscillating between joy and sadness after receiving the news.