Circasemidian rhythm

Last updated

In chronobiology, a circasemidian rhythm is a physiological arousal cycle that peaks twice in a 24-hour day. It may also be called the semicircadian rhythm. Numerous studies have demonstrated that human circadian rhythms in many measures of performance and physiological activity have a 2-peak daily (circasemidian) pattern. [1] The word, circasemidian, is based upon the Latin words circa ("about"), semi ("half") and dia ("day"). Thus, this is a rhythm that has two cycles per day, and some investigators have referred to it as the semicircadian rhythm. It usually serves to (1) deepen the pre-dawn nadir in body temperature and cognitive performance, (2) create a flat spot during the early afternoon in the daytime increase in body temperature and cognitive performance (the "post-lunch dip"), and (3) heighten the early-evening peak in body temperature and cognitive performance. [2] Broughton was the first to bring this characteristic of human performance to the attention of researchers. [3]

Contents

Evidence

No evidence exists to support the presence of a circasemidian rhythm in the rhythmic cells of the suprachiasmatic nucleus, the accepted internal timing source for the major circadian rhythms of the body. Thus, though it falls in the domain of an ultradian rhythm, the circasemidian rhythm may be the first harmonic of the circadian rhythm and not an intrinsic rhythm. However, a number of published data sets have shown a daily two-peak error pattern in industrial and transportation environments. [4] The pattern was also obvious in many of the charts shown in the review by Rutenfranz and Colquhoun, [5] though they did not suggest a circasemidian rhythm as a mediator for the pattern. Other investigators have reported a circasemidian rhythm in body temperature, [6] melatonin [7] and slow-wave sleep. [8]

Recommendation

These behavioral and physiological observations support the need to consider a 12-hour rhythmicity in the quantification of daily variations in physiological function and some kinds of cognitive performance in fatigue modeling efforts such as the Fatigue Avoidance Scheduling Tool.

Related Research Articles

<span class="mw-page-title-main">Jet lag</span> Physiological condition caused by travel across time zones

Jet lag is a temporary physiological condition that occurs when a person's circadian rhythm is out of sync with the time zone they are in, and is a typical result from travelling rapidly across multiple time zones. For example, someone travelling from New York to London, i.e. from west to east, feels as if the time were five hours earlier than local time, and someone travelling from London to New York, i.e. from east to west, feels as if the time were five hours later than local time. The phase shift when travelling from east to west is referred to as phase-delay of the circadian cycle, whereas going west to east is phase-advance of the cycle. Most travellers find that it is harder to adjust time zones when travelling east. Jet lag was previously classified as a circadian rhythm sleep disorder.

<span class="mw-page-title-main">Circadian rhythm</span> Natural internal process that regulates the sleep-wake cycle

A circadian rhythm, or circadian cycle, is a natural oscillation that repeats roughly every 24 hours. Circadian rhythms can refer to any process that originates within an organism and responds to the environment. Circadian rhythms are regulated by a circadian clock whose primary function is to rhythmically co-ordinate biological processes so they occur at the correct time to maximize the fitness of an individual. Circadian rhythms have been widely observed in animals, plants, fungi and cyanobacteria and there is evidence that they evolved independently in each of these kingdoms of life.

<span class="mw-page-title-main">Chronobiology</span> Study of rhythms in biological processes of living organisms

Chronobiology is a field of biology that examines timing processes, including periodic (cyclic) phenomena in living organisms, such as their adaptation to solar- and lunar-related rhythms. These cycles are known as biological rhythms. Chronobiology comes from the ancient Greek χρόνος, and biology, which pertains to the study, or science, of life. The related terms chronomics and chronome have been used in some cases to describe either the molecular mechanisms involved in chronobiological phenomena or the more quantitative aspects of chronobiology, particularly where comparison of cycles between organisms is required.

<span class="mw-page-title-main">Delayed sleep phase disorder</span> Chronic sleep disorder

Delayed sleep phase disorder (DSPD), more often known as delayed sleep phase syndrome and also as delayed sleep–wake phase disorder, is the delaying of a person's circadian rhythm compared to those of societal norms. The disorder affects the timing of biological rhythms including sleep, peak period of alertness, core body temperature, and hormonal cycles. People with this disorder are often called night owls.

Shift work is an employment practice designed to keep a service or production line operational at all times. The practice typically sees the day divided into shifts, set periods of time during which different groups of workers perform their duties. The term "shift work" includes both long-term night shifts and work schedules in which employees change or rotate shifts.

Non-24-hour sleep–wake disorder is one of several chronic circadian rhythm sleep disorders (CRSDs). It is defined as a "chronic steady pattern comprising [...] daily delays in sleep onset and wake times in an individual living in a society". Symptoms result when the non-entrained (free-running) endogenous circadian rhythm drifts out of alignment with the light–dark cycle in nature. Although this sleep disorder is more common in blind people, affecting up to 70% of the totally blind, it can also affect sighted people. Non-24 may also be comorbid with bipolar disorder, depression, and traumatic brain injury. The American Academy of Sleep Medicine (AASM) has provided CRSD guidelines since 2007 with the latest update released in 2015.

A phase response curve (PRC) illustrates the transient change in the cycle period of an oscillation induced by a perturbation as a function of the phase at which it is received. PRCs are used in various fields; examples of biological oscillations are the heartbeat, circadian rhythms, and the regular, repetitive firing observed in some neurons in the absence of noise.

A zeitgeber is any external or environmental cue that entrains or synchronizes an organism's biological rhythms, usually naturally occurring and serving to entrain to the Earth's 24-hour light/dark and 12-month cycles.

<span class="mw-page-title-main">Circadian rhythm sleep disorder</span> Family of sleep disorders that affect the timing of sleep

Circadian rhythm sleep disorders (CRSD), also known as circadian rhythm sleep–wake disorders (CRSWD), are a family of sleep disorders that affect the timing of sleep. CRSDs cause a persistent pattern of sleep/wake disturbances that arise either by dysfunction in one's biological clock system, or by misalignment between one's endogenous oscillator and externally imposed cues. As a result of this misalignment, those affected by circadian rhythm sleep disorders can fall asleep at unconventional time points in the day, or experience excessive daytime sleepiness if they resist. These occurrences often lead to recurring instances of disrupted rest and wakefulness, where individuals affected by the disorder are unable to go to sleep and awaken at "normal" times for work, school, and other social obligations. Delayed sleep phase disorder, advanced sleep phase disorder, non-24-hour sleep–wake disorder and irregular sleep–wake rhythm disorder represent the four main types of CRSD.

Shift work sleep disorder (SWSD) is a circadian rhythm sleep disorder characterized by insomnia, excessive sleepiness, or both affecting people whose work hours overlap with the typical sleep period. Insomnia can be the difficulty to fall asleep or to wake up before the individual has slept enough. About 20% of the working population participates in shift work. SWSD commonly goes undiagnosed, and it is estimated that 10–40% of shift workers have SWSD. The excessive sleepiness appears when the individual has to be productive, awake and alert. Both symptoms are predominant in SWSD. There are numerous shift work schedules, and they may be permanent, intermittent, or rotating; consequently, the manifestations of SWSD are quite variable. Most people with different schedules than the ordinary one might have these symptoms but the difference is that SWSD is continual, long-term, and starts to interfere with the individual's life.

A chronotype is the behavioral manifestation of underlying circadian rhythm's myriad of physical processes. A person's chronotype is the propensity for the individual to sleep at a particular time during a 24-hour period. Eveningness and morningness are the two extremes with most individuals having some flexibility in the timing of their sleep period. However, across development there are changes in the propensity of the sleep period with pre-pubescent children preferring an advanced sleep period, adolescents preferring a delayed sleep period and many elderly preferring an advanced sleep period.

Light effects on circadian rhythm are the response of circadian rhythms to light.

David F. Dinges is an American sleep researcher and teacher.

<span class="mw-page-title-main">Effects of fatigue on safety</span>

Fatigue is a major safety concern in many fields, but especially in transportation, because fatigue can result in disastrous accidents. Fatigue is considered an internal precondition for unsafe acts because it negatively affects the human operator's internal state. Research has generally focused on pilots, truck drivers, and shift workers.

<span class="mw-page-title-main">Charles Czeisler</span> American physician and sleep researcher

Charles Andrew Czeisler is a Hungarian-American physician and sleep and circadian researcher. He is a leading researcher and author in the fields of the effects of light on human physiology, circadian rhythms and sleep medicine.

Studies, which include laboratory investigations and field evaluations of population groups that are analogous to astronauts, provide compelling evidence that working long shifts for extended periods of time contributes to sleep deprivation and can cause performance decrements, health problems, and other detrimental consequences, including accidents, that can affect both the worker and others.

A constant routine protocol is a common method used in human circadian rhythm research to study internally generated, or endogenous, circadian rhythms without the effect of external, or exogenous, influences. In the method, subjects are kept in constant conditions for at least 24 hours. These include constant light and temperature, as well as constant semi-recumbent posture. In addition, subjects' food intake is evenly distributed throughout the protocol, and subjects are typically not allowed to sleep for the duration. While in these conditions, subjects are often assessed for a number of variables of interest. Two of the most common and best understood of these variables are core body temperature and melatonin.

<span class="mw-page-title-main">Charmane Eastman</span> American academic research scientist in chronobiology

Charmane Eastman is an American academic research scientist whose career has focused on studying circadian rhythms and their relationships to sleep, jet lag, and shift work. She has also studied winter depression, more properly known as seasonal affective disorder (SAD). Of special focus are the effects of bright light and melatonin on circadian rhythms.

Anne-Marie Chang is a researcher in the fields of sleep and circadian rhythms and is currently an Assistant Professor of Bio-behavioral Health at Pennsylvania State University. She earned her Ph.D. in neuroscience from Northwestern University in 2003.

Elizabeth Klerman is a professor of neurology at Harvard Medical School. Her research focuses on applying circadian and sleep research principles to human physiology and pathophysiology. She also uses mathematical analysis and modeling to study human circadian, sleep, and objective neurobehavioral performance and subjective (self-reported) mood and alertness rhythms.

References

  1. ↑ Mitler MM, Carskadon MA, Czeisler CA, Dement WC, Dinges DF, Graeber RC. "Catastrophes, sleep, and public policy: consensus report". Sleep11:100-109, 1988.
    - Eastman C. "Are separate temperature and activity oscillators necessary to explain the phenomena of human circadian rhythms?" In: Moore-Ede MC, Czeisler CA, editors. Mathematical Models of the Circadian Sleep-Wake Cycle. New York, Raven, 1984. pp. 81–103.
    - US Congress Office of Technology Assessment. Biological Rhythms: Implications for the Worker. Washington DC, US Government Printing Office, 1991.
  2. ↑ Miller, J. C. (2006). In Search of Circasemidian Rhythms . Report no. 2006-0074. Brooks City-Base TX: Air Force Research Laboratory.
  3. ↑ Broughton RJ. "SCN controlled circadian arousal and the afternoon "nap zone"." Sleep Res Online1(4):166-178, 1998,
    - Broughton RJ. "Biorhythmic variations in consciousness and psychological functions". Canadian Psychological Reviews16:217-230, 1975.
    - Broughton RJ. "Chronobiological aspects and models of sleep and napping". In: Dinges DF, Broughton RJ (eds.), Sleep and Alertness: Chronobiological, Behavioral and Medical Aspects of Napping. New York, Raven Press, 71-98, 1989.
  4. ↑ Bjerner B, Holm A, Swennson A. "Diurnal variation in mental performance: A study of three-shift workers". Br J Ind Med12:103-110, 1955.
    - Browne RC. "The day and night performance of teleprinter switchboard operators". Occupational Psychology23:1-6, 1949.
    - Folkard S, Lombardi DA, Tucker PT. "Shiftwork: safety, sleepiness and sleep". Industrial Health43:20–23, 2005.
    - Harris W. "Fatigue, circadian rhythm, and truck accidents". Chapter 8 in Mackie RR (ed.), Vigilance: Operational Performance, and Physiological Correlates. New York, Plenum Press, 1977.
    - Harris W. "Relationships between length of time driving, time of day, and certains kinds of accidents". Pages 51-64 in Mackie RR, Miller JC, Effects of Hours of Service, Regularity of Schedules, and Cargo Loading on Truck and Bus Driver Fatigue (NTIS PB290957). Goleta CA, Human Factors Research, Inc., 1978.
    - Hildebrandt G, Rohmert W, Rutenfranz J "12 and 24 h rhythms in error frequency of locomotive drivers and the influence of tiredness". Int J Chronobiology2:175-180, 1974.
    - Kogi K, Ohta T. "Incidence of near accidental drowsing in locomotive driving during a period of rotation". J Human Ergology4:65-76, 1975.
    - Langlois PH, Smolensky MH, His BP, Weir FW. "Temporal patterns of reported single-vehicle car and truck accidents in Texas, USA, during 1980-1983". Chronobiologia2:131-140, 1985.
    - Lavie P, Wollma M, Pollack I. "Frequency of sleep–related traffic accidents and hour of the day". Sleep Research15:275, 1986.
    - Mitler MM. "Two-peak patterns in sleep, mortality and error". Proc Intl Sympos on Sleep and Health Risk, Springer Verlag, 1989.
    - Prokop O, Prokop L. "Ermuding und einschlafen am steuer". Dtsch Z Gerichtl Med44:343-355, 1955.
  5. ↑ Rutenfranz J, Colquhoun P. "Circadian rhythms in human performance". Scand J Work Environ & Health5:167-177, 1979.
  6. ↑ Colquhoun WP, Blake MJF, Edwards RS. "Experimental studies of shift-work I: A comparison of 'rotating' and 'stabilized' 4-hours shift systems". Ergonomics11:437-453, 1968.
    - Colquhoun WP, Paine MWPH, Fort A. "Circadian rhythm of body temperature during prolonged undersea voyages". Aviat Space Environ Med49(5):671-678, 1978.
    - Colquhoun WP, Paine MWPH, Fort A. "Changes in the temperature rhythm of submariners following a rapidly rotating watchkeeping system for a prolonged period". Int. Arch. Occup. Environ. Health42:185-190, 1979.
    - Martineaud JP, Cisse F, Samb A. "Circadian variability of temperature in fasting subjects". Scripta Medica (Brno)73(1):15–24, 2000.
  7. ↑ Maggioni C, Cornelissen G, Antinozzi R, Ferrario M, Grafe A, Halberg F. "A half-yearly aspect of circulating melatonin in pregnancies complicated by intrauterine growth retardation". Neuroendicrinology Letters20:55-68, 1999.
  8. ↑ Hayashi M, Morikawa T, Hori T. "Circasemidian 12 h cycle of slow wave sleep under constant darkness". Clin Neurophysiol113(9):1505-16, 2002.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.