circadian

[ sur-key-dee-uhn ]

adjective

, Physiology.

1. of or relating to a biorhythm or regular biological cycle occurring once every 24 hours, such as waking and sleeping: Compare infradian ( def ), ultradian ( def ).

   Exposure to blue light at night can disrupt your circadian rhythm, making your biological clock think it's earlier in the day rather than time for bed.

   He is doing research related to the circadian cycling of hormones.

circadian

/ sɜːˈkeɪdɪən /

adjective

1. See biological clock
   of or relating to biological processes that occur regularly at about 24-hour intervals, even in the absence of periodicity in the environment See also biological clock

Word History and Origins

Origin of circadian¹

First recorded in 1955–60; from circā “about” + Latin di(ēs) “day” + -an ( def ); circa ( def )

Word History and Origins

Origin of circadian¹

C20: from Latin circa about + diēs day

Example Sentences

In the daytime, light enters the retina and stimulates the hypothalamus, the part of the brain that maintains circadian rhythms, letting the body know it’s time to be awake and functioning.

From Popular-Science

Our bodies’ circadian rhythms function best with established routines, predictable light, and lower noise levels.

From Popular-Science

While blue light has gotten a bad rap for disrupting our circadian rhythms, research suggests that it’s only stimulating when it’s too bright.

From Popular-Science

While it’s true that our circadian rhythms directly affect our digestive activity, as biologist Lawrence Scheving detailed in the journal Gastroenterology, those individual patterns rarely sync up with the time on a clock.

From Washington Post

The full cycle was 18 hours, which meant the timing of our circadian cycles were constantly changing.

From Nautilus

Bright light is what keeps our circadian rhythms in good order.

From The Daily Beast

Lighting signals your body's circadian rhythm and can have a strong effect on your mood.

From The Daily Beast

“One of the most important things you can do for your sleep is to have a routine to keep your circadian rhythm normal,” says Suh.

From The Daily Beast

In general, Tb's showed a marked circadian cycle in phase with photoperiod.

From Project Gutenberg

Related Words

• constantly
• day-to-day
• everyday
• often
• periodic
• regular
• regularly
• routine