Other Free Encyclopedias » Medicine Encyclopedia » Aging Healthy - Part 1 » Circadian Rhythms - The Study Of Circadian Rhythms In The Laboratory, Relationship Of Sleep To Circadian Rhythmicity, Circadian Rhythms In Older Subjects.

Circadian Rhythms - Figure Legend

age aging physiological clinical sleep czeisler subjects duffy

(A basic description of Figure 1 on page 233 is listed with the figure. This is a more detailed description.)

Filled symbols refer to the older subjects; open symbols to the young subjects; means = standard errors. Data are double plotted and shown with respect to circadian phase (lower axis) derived from core body temperature data (nadir temperature waveform = 0¤). The corresponding time of day under normal conditions for the older subjects is shown in the upper axis. Lower panel: percent of wakefulness during scheduled sleep. Middle panel: subjective early awakening. Upper panel: normalized cognitive performance.

There are prominent circadian variations in objective and subjective sleep quality and performance, with all showing a nadir at the circadian phases corresponding to the early morning hours. Older subjects show greater objective and subjective sleep disruption at all circadian phases, and there is a much narrower range of circadian phases when older subjects can remain asleep; young subjects can maintain high sleep quality for many hours after their typical wake time, while older subjects experience increasing levels sleep disruption when scheduled to sleep at or just after the time of their circadian temperature nadir (0¤, on average at 5:15 a.m.). This is also reflected in the circadian performance rhythm, where young subjects show impaired performance at and just after the circadian phases corresponding to their usual wake time, while the performance of the older subjects is improving at these phases.

These measures of sleep and wake indicate that there is a change in the interaction between the circadian timing system and sleep with age, and that there appears to be a decreased drive for sleep in older subjects in the early morning hours.

The figure was adapted from the following sources: Duffy, J. F.; D. F. Dijk; E. B. Klerman; and C. A. Czeisler. "Later Endogenous Circadian Temperature Nadir Relative to an Earlier Wake Time in Older People." American Journal of Physiology 275 (1998): R1478–R1487; and Dijk, D. J.; J. F. Duffy; E. Riel; T. L. Shanahan; and C. A. Czeisler. "Ageing and the Circadian and Homeostatic Regulation of Human Sleep During Forced Desynchrony of Rest, Melatonin and Temperature Rhythms. Journal of Physiology (London) 516 2 (1999): 611–627.

BIBLIOGRAPHY

Aschoff, J. "Circadian Rhythms in Man: A Self-sustained Oscillator with an Inherent Frequency underlies Human 24-hour Periodicity." Science 148 (1965): 1427–1432.

Brainard, G. C.; Rollag, M. D.; and Hanifin, J. P. "Photic Regulation of Melatonin in Humans: Ocular and Neural Signal Transduction." Journal of Biological Rhythms 12 (1997): 537–546.

Czeisler, C. A.; Duffy, J. F.; Shanahan, T. L.; Brown, E. N.; Mitchell, J. F.; Rimmer, D. W.; Ronda, J. M.; Silva, E. J.; Allan, J. S.; Emens, J. S.; Dijk, D. J.; and Kronauer, R. E. "Stability, Precision, and Near-24-hour Period of the Human Circadian Pacemaker." Science 284 (1999):2177–2181.

Czeisler, C. A.; Weitzman, E. D.; Moore-Ede, M. C.; Zimmerman, J. C.; and Knauer, R. S. "Human Sleep: Its Duration and Organization Depend on Its Circadian Phase." Science 210: 1264–1267, 1980.

Czeisler, C. A., and Wright, K. P., Jr. "Influence of Light on Circadian Rhythmicity in Humans." In F. W. Turek, and P. C. Zee eds., Regulation of Sleep and Circadian Rhythms. New York: Marcel Dekker, Inc. 1999.

Daan, S.; Beersma, D. G. M.; and Borbély, A. A. "Timing of Human Sleep: Recovery Process Gated by a Circadian Pacemaker." American Journal of Physiology 24 (1984): R161–R178.

Dijk, D.-J., and Czeisler, C. A. "Paradoxical Timing of the Circadian Rhythm of Sleep Propensity Serves to Consolidate Sleep and Wakefulness in Humans." Neuroscience Letters 166 (1994): 63–68.

Dijk, D.-J.; Duffy, J. F.; and Czeisler, C. A. "Age-related Increase in Awakenings: Impaired Consolidation of Non-REM Sleep at All Circadian Phases." Sleep 5 (2001): 565–582.

Duffy, J. F. "Constant Routine." In M. A. Carskadon ed., Encyclopedia of Sleep and Dreaming. New York: Macmillan, 1993.

Duffy, J. F.; Dijk, D. J.; Klerman, E. B.; and Czeisler, C. A. "Later Endogenous Circadian Temperature Nadir Relative to an Earlier Wake Time in Older People." American Journal of Physiology 275 (1998): R1478–R1487.

Foley, D. J.; Monjan, A. A.; Brown, S. L.; Simonsick, E. M.; Wallace, R. B.; and Blazer, D. G. "Sleep Complaints among Elderly Persons: An Epidemiologic Study of Three Communities." Sleep 18 (1995): 425–432.

Klein, D. C., and Moore, R. Y. "Pineal N-Acetyltransferase and Hydroxyindole-OMethyltransferase: Control by the Retinohypothalamic Tract and the Suprachiasmatic Nucleus." Brain Research 174 (1979): 245–262.

Klein, D. C.; Moore, R. Y.; and Reppert, S. M. Suprachiasmatic Nucleus: The Mind's Clock. New York: Oxford University Press, 1991.

Kleitman, N. Sleep and Wakefulness. Chicago: University of Chicago Press, 1939.

Miles, L. E., and Dement, W. C. "Sleep and Aging." Sleep 3 (1980): 119–220.

Monk, T. H. "Circadian Rhythms in Subjective Activation, Mood, and Performance Efficiency." In M. H. Kryger, T. Roth, and W. C. Dement eds., Principles and Practice of Sleep Medicine. Philadelphia: W. B. Saunders Company, 1994.

Moore, R. Y. "Circadian Rhythms: Basic Neurobiology and Clinical Applications." Annual Review of Medicine 48 (1997): 253–266.

Pittendrigh, C. S. "Temporal Organization: Reflections of a Darwinian Clock-Watcher." Annual Review of Physiology 55 (1993): 17–54.

Pittendrigh, C. S., and Daan, S. "Circadian Oscillations in Rodents: A Systematic Increase of Their Frequency with Age." Science 186 (1974): 548–550.

Prinz, P. N.; Vitiello, M. V.; Raskind, M. A.; and Thorpy, M. J. "Geriatrics: Sleep Disorders and Aging." New England Journal of Medicine 323 (1990): 520–526.

Reppert, S. M., and Weaver, D. R. "Molecular Analysis of Mammalian Circadian Rhythms." Annual Review of Physiology 36 (2001): 647–676.

Turek, F. W., and Czeisler, C. A. "Role of Melatonin in the Regulation of Sleep." In F. W. Turek and P. C. Zee eds., Regulation of Sleep and Circadian Rhythms. New York: Marcel Dekker, 1999.

Van Cauter, E.; Plat, L.; Leproult, R.; and Copinschi, G. "Alterations of Circadian Rhythmicity and Sleep in Aging: Endocrine Consequences." Hormone Research 49 (1998): 147–152.

Weaver, D. R. "Melatonin and Circadian Rhythmicity in Vertebrates: Physiological Roles and Pharmacological Effects." In F. W. Turek and P. C. Zee eds., Regulation of Sleep and Circadian Rhythms. New York: Marcel Dekker, 1999.

Wever, R. A. The Circadian System of Man: Results of Experiments under Temporal Isolation. New York: Springer-Verlag, 1979.

JEANNE F. DUFFY CHARLES A. CZEISLER

CLINICAL NURSE SPECIALIST

See NURSE PRACTITIONER

[back] Circadian Rhythms - Summary

User Comments

The following comments are not guaranteed to be that of a trained medical professional. Please consult your physician for advice.

Your email address will be altered so spam harvesting bots can't read it easily.
Hide my email completely instead?

Cancel or