Circadian Rhythm

A circadian rhythm (/sərˈkeɪdiən/), or circadian cycle, is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours. It can refer to any process that originates within an organism (is endogenous) and responds to the environment (entrained by the environment).


Cluster Number:
Wiki Number: W042
Diagnosis: Circadian Rhythm Sleep Disorder
US Patients:
World Patients:
Sex Ratio:
Age Onset:
Brain Area: suprachiasmic nucleus
Symptoms: falling asleep in daytime; biological clock misaligned with circadian rhythm.
Causes: intrinsic: delayed, advanced, irregular or blindness; extrinsic: shift–work, jet-lag; Alzheimer’s often destroys patterns
Medications: None listed.
Therapies: chronotherapy-delay to normalize; light therapy; hypnotics; melotonin in evening; dark therapy

Youtube Video: Circadian Rhythm Disorders

Amazon or Library Book: Sleep . . . Natural Remedies

Amazon or Library Book:

How to Sleep Well

Click the book to link or order from Amazon.

Click the book to link or order from Amazon.

Support Group:; (Circadian Sleep Disorders Network)


The world-wide medical research
reports chosen for each diagnosis 

Clicking each title opens the
PubMed article’s summary-abstract.

  • A Conservative Approach by Unilateral Maximal Single-Muscle Recession Surgery for the Treatment of Cyclic Esotropia
    by Cem Evereklioglu on January 26, 2023

    CONCLUSION: This is the first report of "one eye single-muscle" surgery for high-angle cyclic esotropia. Conservative unilateral medial rectus recession seems to be sufficient to permanently block the circadian rhythm and restore binocular fusion and stereopsis.

  • Alleviation of imiquimod-induced psoriasis-like symptoms in Rorα-deficient mouse skin
    by Koog Chan Park on January 26, 2023

    Retinoic acid receptor-related orphan receptor α (RORα) plays a vital role in various physiological processes, including metabolism, cancer, circadian rhythm, cerebellar development, and inflammation. Although RORα is expressed in the skin, its role in skin physiology remains poorly elucidated. Herein, Rorα was expressed in the basal and suprabasal layers of the epidermis; however, keratinocyte-specific Rorα deletion did not impact normal epidermal formation. Under pathophysiological conditions,...

  • Sleep disturbance in post COVID-19 conditions: Prevalence and quality of life
    by Rimawati Tedjasukmana on January 26, 2023

    Post COVID-19 conditions are complaints and symptoms in patients with a history of probable or confirmed COVID-19 after 3 months of the onset of COVID-19 and last at least 2 months. About 10-20% of people may experience post COVID-19 conditions, one of which is sleep disturbance. There is a wide range of prevalence of sleep disturbances from 6% to more than 70%. An online survey of the post COVID-19 conditions in various countries showed that 78.58% of subjects had sleep disturbances, including...

  • Effects of packing on the diurnal rhythms of respiratory and heart rates in donkeys during the hot-dry season
    by Ayodele Stephen Ake on January 26, 2023

    This study aimed to evaluate the effects of packing (load carrying) on the diurnal rhythms of respiratory and heart rates in donkeys during the hot-dry season. Twenty 2- to 3-years-old donkeys weighing 93 ± 2.7 kg were divided into two groups to serve as subjects: Group 1 was subjected to packing + trekking, while group 2 was subjected to trekking only. All donkeys trekked 20 km on each experimental day. The procedure was repeated three times at one-day intervals. Thermal environmental...