circadian clock
Internal day-night cycle
The circadian clock is the internal biological mechanism that regulates the roughly 24-hour cycle of physiological processes in living organisms.
It governs sleep-wake patterns, hormone release, body temperature, and metabolism.
Jet lag disrupts the circadian clock.
The clock responds to light cues but persists even in constant darkness, demonstrating its endogenous nature.
Circadian rhythm regulator
- hypothalamusSubthalamic regulatory brain region
- pineal glandMelatonin-secreting brain structure
- sleep-wake cycleDaily pattern of rest
- biological rhythmsRecurring physiological cycles
homeostasis · neuroendocrine · gene expression · oscillator · endogenous · entrainment · photoreceptor · retina
Post-flight sleep disruption
- shift workLabor in timed blocks
- fatigueWeariness from prolonged exertion
- disorientationLoss of spatial awareness
- time zonesRegional clock-setting divisions
adaptation · recovery · light pollution · blue light · all-nighter · red-eye flight · overnight shift
Active during darkness
- 24-hourContinuous, without closing
- periodicityRecurring at regular intervals
- oscillationRepeated back-and-forth movement
- phase shiftChange in wave timing
synchronization · dawn · dusk · free-running · amplitude · nadir · cycle
Daily rest-activity pattern
- wakefulnessState of being conscious
- sleepinessState of needing rest
- awakeningReturn to consciousness
- insomniaPersistent inability to rest
sleep stages · REM · drowsiness · alertness · napping · sleep pressure · sleep debt · sleep hygiene
Study of living timing patterns
- chronotherapyTime-optimized medical treatment
- light therapyTreatment using bright lamps
- sleep studiesMedical tests during rest
melatonin
Circadian rhythm regulator
- hypothalamusSubthalamic regulatory brain region
- pineal glandMelatonin-secreting brain structure
- sleep-wake cycleDaily pattern of rest
biological rhythms · homeostasis · neuroendocrine · gene expression · oscillator · endogenous · entrainment · photoreceptor · retina · nucleus
jet lag
Post-flight sleep disruption
- shift workLabor in timed blocks
- fatigueWeariness from prolonged exertion
- disorientationLoss of spatial awareness
time zones · adaptation · recovery · light pollution · blue light · all-nighter · red-eye flight · overnight shift
nocturnal
Active during darkness
- 24-hourContinuous, without closing
- periodicityRecurring at regular intervals
- oscillationRepeated back-and-forth movement
phase shift · synchronization · dawn · dusk · free-running · amplitude · nadir · cycle
sleep-wake
Daily rest-activity pattern
- wakefulnessState of being conscious
- sleepinessState of needing rest
- awakeningReturn to consciousness
insomnia · sleep stages · REM · drowsiness · alertness · napping · sleep pressure · sleep debt · sleep hygiene · chronotype
chronobiology
Study of living timing patterns
- chronotherapyTime-optimized medical treatment
- light therapyTreatment using bright lamps
- sleep studiesMedical tests during rest
- biorhythmssleep cycles, sleep-wake cycle, melatonin, sleep cycle, biorhythm
- sleepsleep, sleeping, nap, doze, slumber
circadian clockmechanical clock
Gear-operated time device
atomic clock · wristwatch · wall clock · digital watch · watch