circadian rhythms
Internal body clock
Circadian rhythms are the biological cycles that repeat roughly every twenty-four hours, governing sleep, hunger, hormone release, and other bodily functions.
The term comes from Latin words meaning "about a day." These internal clocks persist even without external cues but synchronize to light and darkness.
Disruptions cause jet lag and shift-work fatigue: My circadian rhythms are completely off after the red-eye flight.
Circadian rhythm regulator
- pineal glandMelatonin-secreting brain structure
- hypothalamusSubthalamic regulatory brain region
- entrainmentRhythmic systems aligning naturally
- oscillationRepeated back-and-forth movement
endogenous · periodicity · phase shift · sleep-wake cycle · chronotype · diurnal · nocturnal · crepuscular
Persistent inability to rest
- sleep disordersConditions impairing rest
- sleep qualityHow restorative nighttime rest is
- sleep hygieneBehaviors promoting better rest
- wakefulnessState of being conscious
alertness · fatigue · drowsiness · REM cycle · sleep deprivation · napping · restoration · night owl
Time-optimized medical treatment
- light therapyTreatment using bright lamps
- metabolismCellular nutrient conversion
- hormonesBloodstream signaling molecules
- endocrine systemHormone-producing gland network
homeostasis · seasonal affective disorder · blue light · mood regulation · immune function · phototherapy
Day's early hours
- eveningLate day period
- nighttimeDark hours between dusk and dawn
- dawnDay's first glow
- duskDimming after sundown
sunrise · sunset · daylight · schedule · routine · activity · rest · body temperature
Regional clock-setting divisions
- adjustmentAlteration to improve fit
- recoveryRegaining what was lost
- eastboundHeading toward sunrise
- westboundMoving toward west
long-haul flight · resynchronization · light exposure · adaptation · reentry · layover · red-eye flight
melatonin
Circadian rhythm regulator
- pineal glandMelatonin-secreting brain structure
- hypothalamusSubthalamic regulatory brain region
- entrainmentRhythmic systems aligning naturally
oscillation · endogenous · periodicity · phase shift · sleep-wake cycle · chronotype · diurnal · nocturnal · crepuscular · gene expression
insomnia
Persistent inability to rest
- sleep disordersConditions impairing rest
- sleep qualityHow restorative nighttime rest is
- sleep hygieneBehaviors promoting better rest
wakefulness · alertness · fatigue · drowsiness · REM cycle · sleep deprivation · napping · restoration · night owl · early bird
chronotherapy
Time-optimized medical treatment
- light therapyTreatment using bright lamps
- metabolismCellular nutrient conversion
- hormonesBloodstream signaling molecules
endocrine system · homeostasis · seasonal affective disorder · blue light · mood regulation · immune function · phototherapy
morning
Day's early hours
dusk · sunrise · sunset · daylight · schedule · routine · activity · rest · body temperature · energy levels
time zones
Regional clock-setting divisions
- adjustmentAlteration to improve fit
- recoveryRegaining what was lost
- eastboundHeading toward sunrise
westbound · long-haul flight · resynchronization · light exposure · adaptation · reentry · layover · red-eye flight
- natural cyclessleep cycle, seasons, tides, water cycle, lunar cycle
- physiologymetabolism, circulation, respiration, homeostasis, digestion
- biorhythmsbiological clocks, biological clock, sleep cycles, body clock, sleep-wake cycle
- insect behaviorsforaging, mating, flight, flying, crawling
- biomathematicsdifferential equations, Michaelis-Menten, pharmacokinetics, feedback loops, exponential growth
- fetal developmentkicking, movement, hiccups, thumb sucking, swallowing
rhythmic, circa, rhythmical, rhythmically, circadian, circadian rhythm