Melissa Kaplan's
Herp Care Collection
Last updated January 1, 2014

Sleep: Something More Than Merely Rest

©2002 Melissa Kaplan

Sleep. Something all humans and most animals do. Whether we fall into bed, curl up in a crevice, or hunker down to lock our toes around a branch, we relinquish consciousness, trust to our surroundings, certain biological sensory systems, or conspecific on guard duty to protect us (or at least alert us if something needs our attention), close our eyes (those of us with moveable eyelids), and slip into the arms of Morpheus - with or without chemical assistance.

What surprises me in working both with humans who have health problems and with animal keepers is that most people are not aware that sleep is something more than just something you can do at any time. Their thinking seems to be that is doesn't matter what time of day or night you sleep, or whether it is dark or light when you are sleeping, sleep is sleep and so any time is fine. Unfortunately, studies on those who work at night and sleep during the day - and on medical residents who are forced to catnap during shifts running in excess of 12-18 hours, our bodies don't work that way. Neither do those of our pets and other animals.

While researchers are still uncovering much of what goes on in our brains and bodies during sleep, the last decade has seen tremendous gains in knowledge of what happens during normal sleep (that is, normal age/health sleep during normal sleep hours) - and what doesn't if we have various illnesses, disorders, are on medication, or don't get the sleep we need when we need it or at the times of day (based on our circadian clocks) when the body expects it.

A general problem in neuroanatomy is that we are still talking at the level of hypothalamus, amygdala, hippocampus, and visual cortex. This is equivalent to describing Americans. Saying that "neurons in the hippocampus are active during sleep" is similar to saying that "American people like horror movies". It is true for some people but not necessarily true for everyone. By the same token, there are approximately 10¹¹ neurons in the human brain (that's more than there are people on this planet). Just as each humans, similarities aside, are unique individuals, so to are neurons probably not as generic as their molecular structure and nuclei appear to be. Much more work is still needed to understand which specific molecules, being released from which specific neurons and reaching which specific receptors in certain neurons are relevant for the changes during sleep. There are lots of fascinating questions to be addressed. - from the lecture notes of Gabriel Krieman, PhD, Biology & Computation and Neural Systems Program, California Institute of Technology, Pasadena CA.

Not only can stress, acquired habits, prescribed and over the counter medications (including herbs and supplements) work against getting a good night's sleep, various illnesses and disorders may dysregulate sleep, or cause malfunctions in the brain during waking and sleep periods.

For example, people with chronic fatigue syndrome and/or fibromyalgia have been found to have alpha wave intrusions during sleep, and delta wave intrusions when awake. Simply put, that means that their brains are putting out awake-relaxed waves while they are asleep, and sound-asleep waves while they are awake. Coupled with the sleep disorders (hypersomnia, hyposomnia, insomnia, sleep apnea) that commonly occur in these patients after onset of the illness, the inappropriate intrusion of these waves and dysregulation of the hypothalamic-pituitary-adrenal axis, noise sensitivity, and more all contribute to the inability to concentrate, memory loss, memory making ability, fatigue not aided by sleep or rest, pain, and more. While medications (sleeping, muscle relaxants, antiseizure) can help improve the length or quality of our sleep, they never fully restore the brain to proper waking and sleeping functioning, indicating that the problem goes much deeper than just "catching forty winks" or getting ones eight (or ten or six) hours of shut-eye a night.

Health and cognitive problems are found in people who do shift work, that is, they are working or winding down from work (or getting ready for work) when their bodies expect them to be asleep - from about 10 PM to 5 AM or so. Aside from the serious road hazards they present (with driving abilities and reaction time as impaired as if they were over the legal limit for alcohol - see Powell et al. below), they have cognitive and other problems.

Similar problems, though not usually tested for and rarely taken into account, can occur in our pets, be they mammals, birds, reptiles, amphibians, fish or invertebrates. Just because an organism doesn't appear to have a very interesting or challenging life or lifestyle doesn't mean that many, if not most, of the biochemical changes that take place in humans during sleep won't also take place in them. If not identical to what happens in humans, the commonalties found in most animals - especially in the immune and endocrine systems - suggest that, even if the specific processes and chemicals aren't identical, or geared to happen at the same time, doesn't mean that something similar isn't happening in a healthy animal body - or not happening in a body deprived of proper sleep.

Something else for pet owners - especially those of exotic species who haven't been kept in large numbers in captivity for a long period of time, or those species that are living longer in captivity due to improved knowledge about their captive care requirements: for many of these species, we are just now starting to scratch the surface of finding out what illnesses they may get and the long-term effects of their captive environment upon them. Their captive environment includes not only their diet, enclosure, heating, and lighting (both the type and the cycles), but also prolonged exposure to the chemicals in their enclosure (or used in it), chemicals in the room their enclosure is in or that they free roam in, and the daily activity cycles of their humans. Everything that goes on around them - and chemicals that enter their bodies - is a variable in the health, wellness and longevity equation. Providing them the daily photoperiods and scotophase they require - both the timing of them and the length of them - is as important as feeding them properly and giving them enough room to live in.

The following articles are just some of the many available out there in scientific journals and health-related publications and websites. Note: for some of these works, you may want to have a good dictionary handy. My personal favorite is OneLook Dictionary, a metadictionary that searches several medical, scientific and general dictionaries at the same time, giving you a choice of sources to review.

Stages of Sleep
From Mechanisms of Sleep, NYU Brain & Behavior Lectures

Beta Waves: very low amplitude, high frequency: Alertness
Alpha Waves: low amplitude, high frequency: Relaxation
Theta Waves: medium amplitude, medium frequency: Early Stages of Sleep
Delta Waves: high amplitude, low frequency: Deep Sleep.

Abstracts: Sleep and Chronic Fatigue Syndrome (CFS).

Alam, MN; McGinty, D*; Szymusiak, R. 1997. Thermosensitive neurons of the diagonal band in rats: Relation to wakefulness and non-rapid eye movement sleep. Brain Res, vol. 752, no. 1-2, pp. 81-89.

Akerstedt, T; Folkard, S. 1997. The three-process model of alertness and its extension to performance, sleep latency, and sleep length. Chronobiol Int, vol. 14, no. 2, pp. 115-123.

Beardsley, T. 1996. Waking Up: Finding a purpose for sleep has been as elusive as rest to an insomniac, but researchers are getting much closer. Scientific American, July 1996.

Bower, Bruce. 1999. Slumber's Unexplored Landscape. Science News, Vol. 156, No. 13, September 25, 1999, p. 205.

Chugh DK, Weaver TE, Dinges DF. Neurobehavioral consequences of arousals. Sleep 1996 Dec;19(10 Suppl):S198-201. [Note: repeated arousals may be a problem in pets and children who sleep in areas where they can be disturbed, even if not brought fully awake, by raised voices, music, etc. See also Reptile Hearing.]]

Cromie, WJ. 1998. Awakening to How We Sleep. Harvard Gazette.

Dinges DF. 1995. An overview of sleepiness and accidents. J Sleep Res 1995 Dec;4(S2):4-14

Dinges DF, Pack F, Williams K, Gillen KA, Powell JW, Ott GE, Aptowicz C, Pack AI. 1997 Cumulative sleepiness, mood disturbance, and psychomotor vigilance performance decrements during a week of sleep restricted to 4-5 hours per night. Sleep 1997 Apr;20(4):267-7 [Note: Due to CFS-induced hyposomnia, I only slept 1.5-2 hours a night for almost 9 years, generally between the hours of 11pm - 2 am. - MK]

Doran SM, Van Dongen HP, Dinges DF. 2001 Sustained attention performance during sleep deprivation: evidence of state instability. Arch Ital Biol 2001 Apr;139(3):253-67.

EurekaAlert! 1998. Two Brandeis Scientists Shed Light On The First Photoreceptor Known To Set Circadian Rhythms.

EurekaAlert! 2001. Exercise effects dependent on time of day.

EurekaAlert! 2001. Sleep in early life may play crucial role in brain development.

EurekaAlert! 2001. Why missing out on a good night's sleep could give you ulcers.

Gary KA, Winokur A, Douglas SD, Kapoor S, Zaugg L, Dinges DF. 1996. Total sleep deprivation and the thyroid axis: effects of sleep and waking activity. Aviat Space Environ Med 1996 Jun;67(6):513-9

Gillis, Anna Maria. 1996. Why Sleep? A new hypothesis suggests that we sleep to refuel energy stores in the brain. Bioscience, Volume 46, Number 6, June 1996

Kavanau, JL. 1997. Origin and evolution of sleep: Roles of vision and endothermy. Brain Res Bull, vol. 42, no. 4, pp. 245-264.

Krueger, JM. 1995. Cytockines as regulators of sleep. Department of Physiology and Biophysics, University of Tennessee, Memphis, Tennessee 38163

Kushikata T; Fang J; Wang Y; Krueger JM. Interleukin 4 (IL-4) Inhibits Spontaneous Sleep In Rabbits. University of Washington Veterinary Medical School.

Luna, TD; French, J; Mitcha, JL. 1997. A study of USAF air traffic controller shiftwork: Sleep, fatigue, activity, and mood analyses Aviat, Space, Environ Med, vol. 68, no. 1, pp. 18-23.

MacKinnon LT. 2000. Special feature for the Olympics: effects of exercise on the immune system: overtraining effects on immunity and performance in athletes. Immunol Cell Biol 2000 Oct;78(5):502-9

Mestel, R. 1997. Noises from the cellar. New Sci, vol. 154, no. suppl., pp. 14-17.

Mullington J, Korth C, Hermann DM, Orth A, Galanos C, Holsboer F, Pollmacher T. 2000. Dose-dependent effects of endotoxin on human sleep. Am J Physiol Regul Integr Comp Physiol 2000 Apr;278(4):R947-55

Murphy, PJ; Campbell, SS. 1996. Physiology of the circadian system in animals and humans. Journal of Clinical Neurophysiology (United States), vol. 13, no. 1, pp. 2-16, 1996

Oren, DA. 1997. Bilirubin, REM sleep, and phototransduction of environmental time cues. A hypothesis. Chronobiol Int, vol. 14, no. 3, pp. 319-329.

Opp MR, Imeri L. 2001. Rat strains that differ in corticotropin-releasing hormone production exhibit different sleep-wake responses to interleukin 1. Neuroendocrinology 2001 Apr;73(4):272-84

Ozturk L, Pelin Z, Karadeniz D, Kaynak H, Cakar L, Gozukirmizi E. 1999. Effects of 48 hours sleep deprivation on human immune profile. Sleep Res Online 1999;2(4):107-11

Pollmacher T, Schuld A, Kraus T, Haack M, Hinze-Selch D, Mullington J. 2000. Experimental immunomodulation, sleep, and sleepiness in humans. Ann N Y Acad Sci 2000;917:488-99

Powell NB, Riley RW, Schechtman KB, Blumen MB, Dinges DF, Guilleminault C. 1999. A comparative model: reaction time performance in sleep-disordered breathing versus alcohol-impaired controls. Laryngoscope 1999 Oct;109(10):1648-54

Redwine L, Hauger RL, Gillin JC, Irwin M. 2000. Effects of sleep and sleep deprivation on interleukin-6, growth hormone, cortisol, and melatonin levels in humans. J Clin Endocrinol Metab 2000 Oct;85(10):3597-603

Sakic, B; (1998). The Role of Interleukin-6 in Autoimmunity-induced Behavioral Dysfunction and Neurodegeneration. Presented at INABIS '98 - 5th Internet World Congress on Biomedical Sciences at McMaster University, Canada, Dec 7-16th. Invited Symposium.

Shearer WT, Reuben JM, Mullington JM, Price NJ, Lee BN, Smith EO, Szuba MP, Van Dongen HP, Dinges DF. 2001. Soluble TNF-alpha receptor 1 and IL-6 plasma levels in humans subjected to the sleep deprivation model of spaceflight. Allergy Clin Immunol 2001 Jan;107(1):165-70

Silberman, S. 2000. To Sleep, Perchance to Feel Better? Crohn's & Colitis Foundation of America.

Takahashi, S; Fang J; Kapás, L; Wang, Y; Krueger, JM. Inhibition of Brain Interleukin-1 Attenuates Sleep Rebound After Sleep Deprivation in Rabbits. University of Washington Veterinary Medical School.

Wall, S. 2000. To Sleep, Perchance to Know Why. Biology 202, Bryn Mawr.

This should be enough to get pet owners thinking seriously about altering their diurnal and nocturnal (and, very likely, crepuscular) pets' daily photoperiod and scotophase (light and dark) periods, timing them so that they run more consistent with the normal periods of the species in the wild. If you would like to find more information, a good place to start is the National Institutes of Health's PubMed gateway into National Library of Medicine's PubMed, and Scirus. More information on sleep disorders can be found at Sleep Disorder/Dysfunction Information & Resources