Ultradian

Ultradian

Ultradian rhythms are recurrent periods or cycles repeated throughout a 24-hour circadian day. (In contrast, infradian rhythms have periods longer than a day, for example the human menstrual cycle.)

The descriptive term ultradian is used in sleep research in reference to the 90-110 minute cycling of the sleep stages during human sleep.

Some of the other ultradian cyclings of the body are hormonal release, heart rate, thermoregulation, urination, bowel activity, nostril dilation and appetite. The last involves rhythmic release of Neuropeptide Y (NPY) and Corticotropin-releasing hormone (CRH), stimulating and inhibiting appetite ultradian rhythms.

Ultradian states in bipolar disorder cycle much faster than "rapid cycling", which is defined as four or more mood episodes in one year, sometimes occurring within a few weeks. Ultradian mood cycling is characterized by cycles shorter than 24 hours.

References

* Ultra-rapid and ultradian cycling in bipolar affective illness. Kramlinger KG, Post RM. Br J Psychiatry. 1996 Mar;168(3):314-23. Associated Articles and Links [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=pubmed_DocSum&cmd=Retrieve&db=pubmed&list_uids=8833685&dopt=Books]


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  • ultradian — (ˌ)əlˈtrādēən adjective Etymology: ultra + dian (as in circadian herein) : being, characterized by, or occurring in periods or cycles (as of biological activity) of considerably less than 24 hours ultradian pulses of insulin secretion an… …   Useful english dictionary

  • ultradian — adjective Cyclical with a periodicity significantly shorter than 24 hours, that is, more frequent than circadian. Ultradian rhythms […] operate in cycles of less than 24 hours, that is they happen more than once a day …   Wiktionary

  • ultradian — Relating to biologic variations or rhythms occurring in cycles more frequent than every 24 hours. Cf.:circadian, infradian. [ultra + L. dies, day] * * * ul·tra·di·an əl trād ē ən adj being, characterized by, or occurring in periods or cycles (as… …   Medical dictionary

  • ultradian — /ul tray dee euhn/, adj. of or pertaining to a biorhythm having a period of less than 24 hours. [1960 65; ULTRA + L di(es) day + AN] * * * …   Universalium

  • ultradian — [ʌl treɪdɪən] adjective Physiology recurring more than once a day (but less than once an hour). Compare with infradian. Origin 1960s: from ultra beyond on the pattern of circadian …   English new terms dictionary

  • ultradian — ul·tra·di·an …   English syllables

  • ultradian — adj. denoting a biological rhythm or cycle that occurs more frequently than once in 24 hours. Compare: circadian, nyctohemeral …   The new mediacal dictionary

  • ultradian rhythm — the regular recurrence in cycles of less than 24 hours from one stated point to another, such as certain biologic activities that occur at such intervals, regardless of conditions of illumination …   Medical dictionary

  • Circadian — Refers to events occurring within a 24 hour period, in the span of a full (24 hour) day, as in a circadian rhythm. The word “circadian” is a 20th century invention. It was coined in 1959 from the Latin “circa” (around) + “diem” (a day). However,… …   Medical dictionary

  • infradian — Relating to biologic variations or rhythms occurring in cycles less frequent than every 24 hours. Cf.:circadian, ultradian. [infra + L. dies, day] * * * in·fra·di·an in frā dē ən adj being, characterized by, or occurring in periods or cycles (as… …   Medical dictionary

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