WANDERING SOLACE
  • Home
  • Archives
  • Author
  • Contact
  • Home
  • Archives
  • Author
  • Contact
Search by typing & pressing enter

YOUR CART

Sleep


​
​Manila, Philippines

October 2015

Picture

"When you have insomnia, you're never really asleep, and you're never really awake."
- From the movie Fight Club

Everyone experiences sleep deprivation now and again but an unhappy subset of these people additionally suffer from a symptom of severe sleep deprivation called insomnia; full-blown insomnia is defined by difficulty with one or more of falling asleep, maintaining sleep, waking up too early, or non-restorative sleep despite adequate opportunities to do so that results in daytime impairment, and the difficulty must occur at least three times a week for one month or longer (1). Insomnia denotes that the human body is conflicted; instead of being either asleep or awake, it tries to be both asleep and awake. Since it is impossible to do both concurrently, the result is a sort of "walking dead" predicament - never really asleep, never really awake. 

Sleep deprivation heralds many negative sequelae including fatigue, reduced immune function, impaired perception, difficulty concentrating, worsened memory, slowed reaction times, heightened aggressiveness, and an increased rate of errors and accidents (2). Regarding that last point, a prospective, randomized study looking at the effects of sleep deprivation in medical training showed that interns working a traditional schedule made 36% more serious medical errors compared to interns under a schedule that included more sleep (3), and one rather large study looking at motor vehicle accidents showed that 20% of them resulted from driver sleepiness (4). In addition to these sequelae of sleep deprivation, people with full-blown insomnia additionally suffer from reduced pain tolerance, an increased risk of diabetes and cardiovascular disease, and psychiatric conditions (2). It has been estimated that a whopping 40% of insomniacs have a coexisting psychiatric condition, depression and anxiety disorders being the most common (5).
​
Sleep deprivation is global. Its prevalence depends upon the population studied, but survey results across many different countries show that 30-40% of all adults report experiencing semi-regular difficulties in one or more of falling asleep, staying asleep, waking up too early, or non-restorative sleep resulting in daytime sleepiness (1,6,7) indicating that billions of people are semi-regularly sleep deprived. The prevalence of specific insomnia disorders is 5-10% (1,8,9) indicating that hundreds of millions of people suffer from full-blown insomnia.


Sleep deprivation and insomnia are clearly bad and afflict far too many people. So the million-dollar question is "How do we treat them?" To answer this question we must first understand normal sleep and the reason it evolved.

Purpose Of Sleep

Many studies define sleep as a natural and reversible state of reduced responsiveness and relative inactivity (10,11). Sleep in mammals consists of two core stages, non-rapid eye movement (NREM) sleep (absent eye movements, reduced muscle tone, and thought-like dreams) and rapid eye movement (REM) sleep (rapid eye movements, absent muscle tone, and emotionally laden dreams). On an electroencephalogram (EEG), NREM sleep is hallmarked by slow, high-amplitude oscillations whereas REM sleep differs considerably and is characterized by fast, low-amplitude oscillations similar to quiet wakefulness (10).

Sleep is vital. If it were not, one would expect to find animals that do not sleep; since sleep makes an animal vulnerable to predators, evolution would have selected against it long ago unless it served an essential function. Yet there is no strong evidence of any animal that does not sleep (11), although not every animal sleeps in the same way. Dolphins move continuously, yet are capable of unihemispheric sleep whereby they put half of the brain to sleep at a time and sleep in a stereotyped circular manner with one eye open so that they can detect threats and periodically surface for air (11,12). Mallard ducks also engage in unihemispheric sleep; ducks located on the edge of a group keep the open eye directed outwards to detect predators (13). Sleep behaviour has been shown in all vertebrate classes including reptiles, amphibians, and fishes as well as many invertebrates, such as insects and worms (14,15,16,17,18,19).

If sleep serves an essential purpose that cannot be eliminated by evolution, what is it? There are many theories. Some are unlikely and only worth mentioning in passing. Some are more substantial and worth contemplating.

We'll discuss some of the unlikely theories first. In the energy conservation theory​, sleep is submitted to be a means of saving energy (20). However, sleep only marginally decreases metabolism by 5-10% (14,21) while hibernating animals such as bears can drop their metabolic rates by as much as 75% (22), yet bears still need to go into rebound sleep after the hibernation period which suggests that they need sleep for something other than energy conservation. The preservation theory posits that sleep protects an animal during the night, when being awake and roaming around might place them at great risk (23). However, a sedentary non-sleeping animal can achieve the same thing. Moreover, carnivores on the top of the food chain sleep the most - for example, adult male lions sleep up to twenty hours a day (24) but they aren't threatened by much, so all that sleep must be needed for something else. Finally, the restitution theory proposes that sleep is a time of total body growth and repair, the key argument of which is the observation that hormones released during sleep such as growth hormone, prolactin, and testosterone exhibit predominantly anabolic functions whereas hormones released during wakefulness such as cortisol are predominantly catabolic (25). However, since this theory was proposed it has been shown that human total body protein synthesis is actually greater during wakefulness than sleep (26), and it is more affected by feeding than by anything else (27), so this theory also fails to explain sleep's purpose.

There are three theories with more grit to them. They relate sleep to the immune system and brain.


(1) Immune Function Theory.

Sleep and immunity are tightly linked - sleep loss impairs immune function, and immune challenge alters sleep (28). Many studies have shown that sleep deprivation impairs the immune system. In rats, sleep restriction for 21 days significantly reduces spleen weight and total white blood cell numbers compared to a control group (29), and rats totally sleep deprived develop bacterial infections within days followed by overwhelming infections and death after a few weeks (30). An analysis of 26 mammalian species showed that those with more total sleep have higher numbers of white blood cells but not red blood cells, and a further analysis of twelve species revealed that a ten hour increase in sleep results in a massive 24-fold reduction in parasitism (31). In addition to sleep deprivation impairing the immune system, the reverse association is also true, that immune challenges affect sleep - for example, rabbits infected by live bacteria show altered sleep patterns over the next two days (32). These observations suggest that sleep is involved in regulating the effectiveness of the immune system.


(2) Waste Clearance Theory.

In the human brain, metabolic waste products such as amyloid proteins accumulate during wakefulness and must be removed lest they reach toxic levels (33). They are removed by a waste clearance pathway called the 
glymphatic system which consists of a route for cerebrospinal fluid to enter brain tissue, coupled to a clearance mechanism for the removal of interstitial fluid and its metabolic waste products. Sleep is associated with a 60% increase in the interstitial space volume, resulting in a striking increase in the removal of waste products from the brain (33), especially in the lateral sleeping position (34). If the brain remained awake at all times then its metabolic waste products would reach toxic levels resulting in death, so sleep may have evolved to regulate this process.

(3) Neural Reorganization Theory.

Many people believe that sleep is the price paid by the brain for its
neuroplasticity, which is its ability to reorganize neural networks in the creation and modification of memories (35). In humans, many studies have shown that sleep deprivation significantly impairs attention and working memory (36,37,38). However, it also impairs long-term memory consolidation, a process that occurs during sleep and involves the transfer of memories of actual experiences from the hippocampus into the neocortex for long-term storage; during long-term memory consolidation, the critical "gist" of a memory is retained while the details are forgotten (36). Many studies have shown that sleep deprivation impairs long-term memory (37) whereas sleep after learning improves long-term memory (36). Furthermore, sleep deprivation impairs stress adaptation - in humans subjected to a stressful experience, restricting REM sleep results in greater anxiety and emotionality compared to control groups (39,40). These observations all suggest that sleep is crucially involved in reorganizing the neural networks of the brain.

Taken together, the immune function theory, waste clearance theory, and neural reorganization theory all hold merit, suggesting that the purpose of sleep is to calibrate the immune system and brain against past waking experiences so that these two systems remain effective during future waking experiences. Thus, when the animal is awake, much of its finite energy reserves are devoted to using the immune system and brain so that it may survive and interact in the world during the present, and when the animal is asleep, much of its energy reserves are devoted to calibrating the immune system and brain so that it may become better at surviving and interacting in the world in the future.

Restoration Of Sleep

The goal of sleep restoration is the establishment of regular, nocturnal sleep periods of sufficient duration and quality such that the symptoms of sleep deprivation are eradicated. First, sleep should be nocturnal, which means no shift work during the night - many studies have shown positive associations between shift work and chronic diseases such as diabetes, cardiovascular disease, and cancer (41,42,43), and while a specific conclusion cannot yet be drawn the strength of the evidence prompted the International Agency for Cancer Research to classify shift work as a probable carcinogen in 2007 (44). Second, the ideal sleep duration for most people is seven to eight hours - sleep of less than six hours or more than nine hours is associated with a modestly increased risk of diabetes, cardiovascular disease, and mortality (45,46). Third, sleep should be of high enough quality that one wakes up feeling refreshed - poorer self-reported sleep quality is associated with a slight increase in mortality (47).

Sleep deprivation and insomnia are clearly associated with problems at night, but certain activities during the day may also help or hinder sleep. Therefore the best approach to sleep restoration includes not only bedtime strategies, but daytime strategies too.

Following are my top four
bedtime strategies for restoring sleep, in sequential order.

(1) Reduce artificial light sources one hour before bedtime.

Darkness is best for sleep, but it has been banished by artificial light over the last two centuries. In 1792, the engineer and inventor William Murdoch first used coal gas to light his house and in 1879, the inventor Thomas Edison's electric light bulbs first illuminated a New York street followed by the modern era of electric lighting (44). Humans are now so inundated with artificial light that when a 1994 earthquake knocked out the power in Los Angeles, many anxious residents called local emergency centers to report seeing a strange “giant, silvery cloud” in the dark sky. What they were seeing, for the first time, was the Milky Way Galaxy, long obliterated by the urban sky glow (44). Exposure to room light before bedtime suppresses the level of melatonin, a hormone released during the biological night that anticipates darkness and sleep, compared to dim light (48). While dimming the lights in the evening is ideal it may not be practical, so a viable alternative is to wear amber-lensed glasses which preferentially block melatonin-suppressing blue light and have been proven to improve sleep quality and mood in a randomized trial (49). The brightness of a television or a computer screen also interferes with melatonin release (50) and it has been shown that watching television before bedtime, or even just having a television in the bedroom, negatively impacts sleep in children (51). Therefore wear amber-lensed glasses, turn off the television, and put away the computer one hour before bedtime.

(2) Drink tart cherry juice 30 minutes before bedtime.

There is only one food that has been shown to unequivocally benefit sleep - tart cherry juice, which is naturally and stratospherically high in melatonin, particularly Montmorency cherries. In a randomized, placebo-controlled trial it was shown that eight ounces of cherry juice twice a day over two weeks significantly increased melatonin levels, reduced napping, and increased sleep time and efficiency in the experimental group compared to the control group (52). Many other studies suggest that small protein or carbohydrate meals half an hour before bedtime may benefit sleep and have positive effects on weight and cardiometabolic parameters (53,54,55), but the evidence is not as strong as it is for tart cherry juice. There are also those who swear by small fat meals to improve sleep (56), but again the evidence is lacking. Therefore
drink tart cherry juice 30 minutes before bedtime.

(3) Lower the body and room temperature right before bedtime.

Cooler temperatures are best for sleep. It is well established that sleep onset is most likely to occur when the core body temperature is declining at its maximum rate (57). Perhaps for this reason, a cold shower before bed can enhance sleep quality (53). Moreover, heat exposure decreases both NREM sleep and REM sleep throughout the night (58). Assuming that one is wearing pajamas and is covered by at least one sheet, the ideal temperature for sleep is 16-19 degrees Celsius (53,59). Therefore
skip the hot bath, take a cold shower, and set the room temperature to 16-19 degrees Celsius right before bedtime.

(4) Replace distracting noises with peaceful ambient noises at bedtime.

Peaceful ambient noises are beneficial for sleep as they mask the perception of distracting night-time noises. Even at low exposure levels, night-time noises such as traffic and voices induce sleep arousals and are associated with cardiovascular disease and stroke in the elderly (60). Possibly the worst offenders in this category are mobile phones, with high mobile phone use associated with sleep disturbances and symptoms of depression among young adults (61). Peaceful ambient noises include music and white noise. It has been shown that 45 minutes of listening to
relaxing music such as classical music before sleep significantly improves sleep quality and reduces depressive symptoms compared to control groups in young adults (62). Exposure to white noise, which is any low intensity, consistently random sound such as a rushing waterfall or wind blowing through trees has been proven to induce sleep in neonates (63) and improve sleep quality in adults after surgery (64). Therefore ditch the phone and listen to relaxing music or white noise at bedtime.

​Following are my top four
daytime strategies for restoring sleep, in sequential order.

(1) Get bright light, especially in the morning.

Bright light in the morning is good for sleep as it appears to regularize one's circadian rhythms. Sunlight is great but may not be available depending on the weather. Two studies have demonstrated that exposure to artificial light from 9 am to 11 am for four weeks increases total sleep times from 5-18% in patients with dementia (65,66). Morning bright light is particularly good for treating sleep onset difficulties, including those induced by eastward air travel jetlag (as an aside, evening bright light is good for treating early morning awakenings, including those induced by westward air travel jetlag) (67). Therefore get that bright light first thing in the morning.

(2) Swap stressful experiences for relaxing experiences during the day.

Stressful daytime experiences can worsen sleep (68,69). The
media is one of the worst offenders (70). The media largely presents news laced with tones of melodrama creating the perception of a hostile, dangerous world - for example, despite an impressive drop in US crime rates since the 1990s, the media has most people believing that crime rates are rising (71). Besides, does up-to-the-minute knowledge of the most recent plane crash, murder, or political scandal enrich our existence or impair it? The media also exposes people to hundreds of advertisements on a daily basis embedded with messages of fear, power, sex, status, and wealth as well as the perfect fantasy life in which health, home, and work are perfectly balanced - not only does this create unrealistic expectations and a feeling that one never has enough, it spoils our appetites for learning about ourselves. The media is one of most stress-inducing sources on the planet and while it's not conclusively proven, probably worsens sleep. 

Fortunately, several relaxing activities have been proven to improve sleep including exercise, massage, yoga, and meditation. Both
aerobic and resistance exercise performed at any time of the day improve sleep quality that same night (72,73), although the afternoon might be the best time to exercise (53). Interestingly, better sleep has also been shown to produce better exercise sessions the following day (74). Having a massage for 15-30 minutes a day three times a week has been shown to improve sleep quality in patients with cancer (75), and yoga classes twice a week for three months have also been shown to improve sleep quality in older adults (76). Finally, a randomized clinical trial demonstrated that mindfulness meditation for two hours a week over six weeks improves sleep quality compared to a control group in older adults (77). 

Therefore
lessen media exposure and replace that time with exercise, massage, yoga, or meditation during the day.

(3) Take a nap in the afternoon.

Taking a nap in the afternoon can combat the effects of sleep deprivation effectively and immediately, even in people who more or less get the sleep they need on a nightly basis (78). Many studies have shown that napping for 10-30 minutes confers considerable benefits in terms of alertness, cognitive performance, and mood in people with either partial or total sleep deprivation (78,79). However, frequent naps longer than 30 minutes are associated with sleep inertia (grogginess) and higher morbidity and mortality, especially among the elderly (79). Therefore take a 10-30 minute nap if tired in the afternoon.

(4) Avoid drugs that mess with the brain, especially in the afternoon and evening.

Several drugs that are often taken for granted - caffeine, nicotine, alcohol, and prescription sedatives - generally impair sleep. 

Caffeine is a stimulant that blocks the receptors of adenosine, a molecule that accumulates in the brain during wakefulness to promote sleep (53). It is present in coffee, most teas, colas, and dark chocolate. Taking caffeine an hour before bedtime shortens total sleep time and shortens the time spent in deep sleep (53), and abstaining from caffeine even for a single day has been shown to significantly improve sleep quality (80). Chamomile tea, which does not contain caffeine, is excluded from this list and may slightly benefit sleep, although the evidence isn't really there. 

Nicotine is both a stimulant and a sedative and it is commonly found in cigarettes and transdermal patches. Nicotine has a biphasic effect on sleep - at low concentrations it leads to relaxation and sedation but at high concentrations it inhibits sleep (53). In general, cigarette smoking and transdermal nicotine patches appear to impair sleep duration and quality (81,82). 

Alcohol is another drug that can act both as a stimulant and as a sedative. A comprehensive review of all scientific studies prior to 2013 examining alcohol and sleep found that alcohol at all dosages before bedtime reduces the time of sleep onset and enhances deep NREM sleep in the first few hours of the night, but it does so at the expense of disrupted REM sleep, particularly in the second half of the night (83). The authors concluded that on the balance, alcohol disrupts sleep, although the effect is minimal at dosages of one to two standard drinks. 

Lastly, a meta-analysis of 24 randomized controlled trials showed that
sedative hypnotics or "sleeping tablets" such as intermediate-acting benzodiazepines (alprazolam, clonazepam, lorazepam, oxazepam, and temazepam) and non-benzodiazepines (zolpidem, zopiclone, zaleplon, and diphenhydramine) modestly improve sleep quality (84). Unfortunately, these drugs also significantly increase the risk of daytime fatigue, memory loss, confusion, disorientation, and falls, especially in older people. Which in many ways defeats the purpose of taking them in the first place. 

​Therefore
avoid caffeine and nicotine, limit alcohol to two standard drinks, and only take sedative hypnotics as a last resort in the afternoon and evening.

Last Words

​Sleep deprivation and insomnia do the immune system and brain a disservice. Ideally, sleep should occur every night for seven to eight hours and it should leave one feeling refreshed in the morning. It's worth summarizing the above strategies for restoring sleep.

Bedtime Strategies

(1) Wear amber-lensed glasses, turn off the television, and put away the computer one hour before bedtime.
​(2) Drink tart cherry juice 30 minutes before bedtime.
(3) Skip the hot bath, take a cold shower, and set the room temperature to 16-19 degrees Celsius right before bedtime.
(4) Ditch the phone and listen to relaxing music or white noise
 at bedtime.

Daytime Strategies

(1) Get that bright light first thing in the morning.
​(2) Lessen media exposure and replace that time with exercise, massage, yoga, or meditation during the day.
​(3) Take a 10-30 minute nap if tired in the afternoon.
​(4) Avoid caffeine and nicotine, limit alcohol to two standard drinks, and only take sedative hypnotics as a last resort
 in the afternoon and evening.

​There's one last thing. If sleep is about calibrating the immune system and brain, then if you aren't exposing these two systems to the diversity and challenge of a life worth living, sleep will be impaired. So while you should try to improve your sleep, make sure you're also truly awake and living well at all other times.

​Solace.

References
(1) Roth T. 2007. Insomnia: Definition, Prevalence, Etiology, and Consequences. Journal of Clinical Sleep Medicine 3(5), S7-S10.
(2) Orzel-Gryglewska J. 2010. Consequences of sleep deprivation. International Journal of Occupational Medicine and Environmental Health 23(1), 95-114.
(3) Landrigan CP, Rothschild JM, Cronin JW, Kaushal R, Burdick E, Katz JT, Lilly CM, Stone PH, Lockley SW, Bates DW, Czeisler CA. 2004. Effects of Reducing Interns' Work Hours on Serious Medical Errors in Intensive Care Units. The New England Journal of Medicine 351, 1838-1848.
​(4) Dingus T, Neale V, Petersen A, Lee S, Sudweeks J, Knipling R. 2006. The 100-car naturalistic driving study, Phase II results of the 100-car field experiment. Washington, DC: National Highway Traffic Safety Administration p 422.
(5) Katz DA, McHorney CA. Clinical correlates of insomnia in patients with chronic illness. Archives of Internal Medicine 158, 1099-1107.

(6) Ancoli-Israel S, Roth T. 1999. Characteristics of insomnia in the United States: Results of the 1991 National Sleep Foundation Survey. I. Sleep 22, Suppl 2, S347-S353.
(7) Hossain JL, Shapiro CM. 2002. The prevalence, cost implications, and cost management of sleep disorders: an overview. Sleep and Breathing 6(2), 85-102. 
(8) Mai E, Buysse DJ. 2008. Insomnia: Prevalence, Impact, Pathogenesis, Differential Diagnosis, and Evaluation. Sleep Medicine Clinics 3(2), 167-174.
(9) Ohayon MM. 2002. Epidemiology of insomnia: What we know and what we still need to learn. Sleep Medicine Reviews 6(2), 97-111.

(10) Rasch B,Born J. 2013. About sleep's role in memory. Physiological Reviews 93, 681-766.
​(11) Cirelli C, Tononi G. 2008. Is Sleep Essential? PLOS Biology 6(8), e216.
(12) Mukhametov LM, Supin AY, Polyakova IG. 1977. Interhemispheric asymmetry of the electroencephalographic sleep patterns in dolphins. Brain Research 134, 581-584.
​(13) Rattenborg NC, Lima SL, Amlaner CJ. 1999. Facultative control of avian unihemispheric sleep under the risk of predation. Behavioural Brain Research 105(2), 163-172.
(14) Schmidt MH. 2014. The energy allocation theory of sleep: A unifying theory of sleep, torpor, and continuous wakefulness. Neuroscience and Behavioral Reviews 47, 122-153.
(15) Flanigan Jr, WF. 1973. Sleep and wakefulness in iguanid lizards, Ctenosaura pectinata and Iguana iguana. Brain, Behaviour and Evolution 8, 401-436.
(16) Lazarev, SG. 1978. Electrographic analysis of wakefulnessand the primary form of sleep in the frog, Rana temporaria. Zhurnal Evolyutsionnoi Biokhimii i Fiziologii 14(4), 379-384.
(17)  ​Zhdanova IV, Wang SY, Leclair OU, Danilova NP. 2001. Melatonin promotes sleep-like state in zebrafish. Brain Research 903, 263–268. 

(18) Hendricks JC, Finn SM, Panckeri KA, Chavkin J, Williams JA, Sehgal A, Pack AI. 2000. Rest in Drosophila is a sleep-like state. Neuron 25, 129–138.
​(19) Raizen DM, Zimmerman JE, Maycock MH, Ta UD, You YJ, Sundaram MV, Pack AI. 2008. Lethargus is a Caenorhabditis elegans sleep-like state. Nature 451, 569–572.
​(20) Berger RJ, Phillips NH. 1995. Energy conservation and sleep. Physiology 8, 276-281.
(21) Amaranath S. 2015. Function of Sleep. ​Scribd website. http://www.scribd.com/doc/13916183/AQA-A-Level-Psychology-PYA4-Function-of-Sleep.
​(22) Toien O, Blake J, Edgar DM, Grahn DA, Heller HC, Barnes BM. 2011. Hibernation in Black Bears: Independence of Metabolic Suppression from Body Temperature. Science 331, 906–909.
(23) WebbWB. 1974. Sleep as an adaptive response. Perceptual and Motor Skills 38, 1023-1027.
​(24) Africa Wildlife website. http://africawildlife.org/lion/.
​(25) Adam K. 1980. Sleep as a restorative process and a theory to explain why. Progress in Brain Research 53, 289-305.
​(26) Clugston GA, Garlick PJ. 1982. The response of protein and energy metabolism in lean and obese man. Human Nutrition - Clinical Nutrition 36C(1), 57-70.
(27) Golden MH, Waterlow JC. 1977. Total protein synthesis in elderly people: a comparison of results with 15N glycine and 14C leucine. Clinical Sleep and Molecular Medicine 53, 277-288.
​(28) Opp MR. 2009. Sleeping to fuel the immune system: mammalian sleep and resistance to parasites. BMC Evolutionary Biology 9(8).
(29) Zager A, Andersen ML, Ruiz FS, Antunes IB, Tufik S. 2007. Effects of acute and chronic sleep loss on immune modulation of rats. American Journal of Physiology - Regulatory, Integrative, and Comparative Physiology 293(1), R504-509.
​(30) Everson CA, Toth LA. 2000. Systemic bacterial invasion induced by sleep deprivation. American Journal of Physiology - Regulatory, Integrative, and Comparative Physiology 278(4), R905-916.
​(31) Preston BT, Capellini I, McNamara P, Barton RA, Nunn CL. 2009. Parasite resistance and the adaptive significance of sleep. BMC Evolutionary Biology 9(7).
​(32) Toth LA, Krueger JM. Effects of microbial challenge on sleep in rabbits. FASEB Journal 3(9), 2062-2066.
​(33) Xie L, Kang H, Xu Q, Chen MJ, Liao Y, Thiyagarajan M, O'Donnell J, Christensen DJ, Nicholson C, Iliff JJ, Takano T, Deane R, Nedergaard M. 2013. Sleep Drives Metabolite Clearance from the Adult Brain. Science 342(6156).
(34) Lee H, Xie L, Yu M, Kang H, Feng T, Deane R, Logan J, Nedergaard M, Benveniste H. 2015. The Effect of Body Posture on Brain Glymphatic Transport. Neurobiology of Disease 35(31), 11034-11044.
​(35) Tononi G, Cirelli C. 2014. Sleep and the Price of Plasticity: From Synaptic and Cellular Homeostasis to Memory Consolidation and Integration. Neuron 1(8), 12-34.
​(36) Wamsley EJ, Stickgold R. 2011. Memory, Sleep, and Dreaming: Experiencing Consolidation. Sleep Medicine Clinics 6(1), 97-108.
​(37) Alhola P, Polo-Kantola P. 2007. Sleep deprivation: Impact on cognitive performance. Journal of Neuropsychiatric Disease and Treatment 3(5), 553-567.
​(38) Turner TH, Drummond SPA, Salamat JS, Brown GG. 2007. Effects of 42 hr of total sleep deprivation on component processes of verbal working memory. Neuropsychology 21(6), 787-795.
​(39) De Koninck JM, Koulack D. 1975. Dream content and adaptation to a stressful situation. Journal of Abnormal Psychology 84(3), 250-260.
(40) Lara-Carrasco J, Nielsen TA, Solomonova E, Levrier K, Popova A. 2009. Overnight emotional adaptation to a negative stimuli is altered by REM sleep deprivation and is correlated with intervening dream emotions. Journal of Sleep Research 18(2), 178-187.
​(41) Wang XS, Armstrong ME, Cairns BJ, Key TJ, Travis RC. 2011. Shift work and chronic disease: the epidemiological evidence. Occupational Medicine 61(2), 78-89.
(42) Frost P, Kolstad HA, Bonde JP. 2009. Shift work and the risk of ischemic heart disease - a systematic review of the epidemiologic evidence. Scandinavian Journal of Work, Environment and Health 35(3), 163-179.
(43) Green CB, Takahashi JS, Bass J. 2008. The meter of metabolism. Cell 134(5), 728-742.
(44) Chepesiuk R. 2009. Missing the Dark: Health Effects of Light Pollution. Environmental Health Perspectives 117(1), A20-A27.
​(45) Nagai M, Hoshide S, Kario K. 2010. Sleep Duration as a Risk Factor for Cardiovascular Disease - a Review of the Recent Literature. Current Cardiology Reviews 6(1), 54-61.
(46) Alvarez GG, Ayas NT. 2004. The impact of daily sleep duration on health: a review of the literature. Progress in Cardiovascular Nursing 19(2), 56-59.
​(47) Martin JL, Fiorentino L, Jouldjian S, Mitchell M, Josephson KR, Alessi CA. 2011. Poor self-reported sleep quality predicts mortality within one year of inpatient post-acute rehabilitation among older adults. Sleep 34(12), 1715-1721.​
​(48) Gooley JJ, Chamberlain K, Smith KA, Khalsa SB, Rajaratnam SM, van Reen E, Zeitzer JM, Czeisler CA, Lockley SW. 2011. Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans. The Journal of Clinical Endocrinology and Metabolism 96(3), E463-E472.
(49) Burkhart K, Phelps JR. 2009. Amber lenses to block blue light and improve sleep: a randomized trial. Chronobiology International 26(8), 1602-11612.
​(50) Higuchi S, Motohashi Y, Liu Y, Ahara M, Kaneko Y. 2003. Effects of VDT tasks with a bright display at night on melatonin, core temperature, heart rate, and sleepiness. Journal of Applied Physiology 94(5), 1773-1776.
​(51) Owens J, Maxim R, McGuinn M, Nobile C, Msall M, Alario A. Television-viewing habits and sleep disturbance in school children. Pediatrics 104(3): e27.
​(52) Liu A, Tipton R, Pan W, Finley J, Prudente A, Karki N, Losso J, Greenway F. 2014. Tart cherry juice increases sleep time in older adults with insomnia. The FASEB Journal 28(1).
​(53) Onen SH, Onen F, Bailly D, Parquet P. 1994. Prevention and treatment of sleep disorders through regulation of sleeping habits. Presse Medicale 23(10), 485-489.
(54) Madzima TA, Panton LB, Fretti SK, Kinsey AW, Ormsbee MJ. 2014. Night-time consumption of protein or carbohydrate results in increased morning resting energy expenditure in active college-aged men. The British Journal of Nutrition 111(1), 71-77.
(55) Waller SM, Vander Wal JS, Klurfeld DM, McBurney MI, Cho S, Bijlani S, Dhurandhar NV. 2004. Evening ready-to-eat cereal consumption contributes to weight management. Journal of the American College of Nutrition 23(4), 316-321.
(56) Bulletproof website. https://www.bulletproofexec.com/the-top-6-ways-to-improve-your-sleep-using-food/.
​(57) Raymann RJEM, van Someren EJW. 2008. Diminished Capability to Recognize the Optimal Temperature for Sleep Initiation May Contribute to Poor Sleep in Elderly People. Sleep 31(9), 1301-1309.
​(58) Okamoto-Mizuno K, Mizuno K. 2012. Effects of thermal environment on sleep and circadian rhythm. Journal of Physiological Anthropology 31(1): 14.
​(59) National Sleep Foundation website. https://sleepfoundation.org/bedroom/touch.php.
​(60) Hume KI, Brink M, Basner M. Effects of environmental noise on sleep. Noise Health 14(61), 297-302.
(61) Thomee S, Harenstam A, Hagberg Mats. 2011. Mobile phone use and stress, sleep disturbances, and symptoms of depression among young adults - a prospective cohort study. BMC Public Health 11: 66.
(62) Harmat L, Takacs J, Bodizs R. 2008. Music improves sleep quality in students. Journal of Advanced Nursing 62(3), 327-335.
​(63) Spencer JA, Moran DJ, Lee A, Talbert D. 1990. White noise and sleep induction. Archives of Disease in Childhood 65(1), 135-137.
(64) Williamson JW. 1992. The effects of ocean sounds on sleep after coronary artery bypass graft surgery. American Journal of Critical Care 1(1), 91-97.
(65) Mishima K, Okawa M, Hishikawa Y, Hozumi S, Hori H, Takahashi K. 1994. Morning bright light therapy for sleep and behavior disorders in elderly patients with dementia. Acta Psychiatrica Scandinavica 89, 1-7.
(66) Yamadera H, Ito T, Suzuki H, Asayama K, Ito R, Endo S. 2001. Effects of bright light on cognitive and sleep-wake (circadian) rhythm disturbances in Alzheimer-type dementia. Psychiatry and Clinical Neurosciences 54, 352-353.
(67) Gooley JJ. 2008. Treatment of circadian rhythm sleep disorders with light. Annals of the Academy of Medicine, Singapore 37(8), 669-676.
(68) Tamrat R, Huynh-Le MP, Goyal M. 2014. Non-Pharmacologic Interventions to Improve the Sleep of Hospitalized Patients: A Systematic Review. Journal of General Internal Medicine 29(5), 788-795.
(69)​ Kompier MA, Taris TW, van Veldhoven M. 2012. Tossing and turning - insomnia in relation to occupational stress, rumination, fatigue, and well-being. Scandinavian Journal of Work, Environment, and Health 38(3), 238-246.
​(70) Charles L. 1999. Why Is Everyone So Cranky? Hyperion.
(71) Howe N. 2015. What's Behind The Decline In Crime? Forbes website. http://www.forbes.com/sites/neilhowe/2015/05/28/whats-behind-the-decline-in-crime/.
​(72) Passos GS, Poyares DL, Santana MG, Tufik S, Mello MT. 2012. Is exercise an alternative treatment for chronic insomnia? Clinics 67(6), 653-660.
(73) Alley JR, Mazzochi JW, Smith CJ, Morris DM, Collier SR. 2015. Effects of resistance exercise timing on sleep architecture and nocturnal blood pressure. Journal of Strength and Conditioning Research 29(5), 1378-1385.
​(74) Baron KG, Reid KJ, Zee PC. 2013. Exercise to improve sleep in insomnia: exploration of the bidirectional effects. Journal of Clinical Sleep Medicine 9(8), 819-824.
​(75) Smith MC, Kemp J, Hemphill L, Vojir CP. 2002. Outcomes of therapeutic massage for hospitalized cancer patients. Journal of Nursing Scholarship 34(3), 257-262.
(76) Halpern J, Cohen M, Kennedy G, Reece J, Cahan C, Baharav A. 2014. Alternative Therapies in Health and Medicine 20(3), 37-46.
(77) Black DS, O'Reilly GA, Olmstead R, Breen EC, Irwin MR. 2015. Mindfulness meditation and improvement in sleep quality and daytime impairment among older adults with sleep disturbances: a randomized clinical trial. JAMA Internal Medicine 175(4), 494-501.
(78) Milner CE, Cote KA. 2009. Benefits of napping in healthy adults: impact of nap length, time of day, age, and experience with napping. Journal of Sleep Research 18, 272-182.
​(79) Dhand R, Sohal H. 2006. Good sleep, bad sleep! The role of daytime naps in healthy adults. Current Opinion in Pulmonary Medicine 12(6), 379-382.
​(80) Sin CW, Ho JS, Chung JW. 2009. Systematic review on the effectiveness of caffeine abstinence on the quality of sleep. Journal of Clinical Nursing 18(1), 13-21.
​(81) Phillips BA, Danner FJ. 1995. Cigarette smoking and sleep disturbance. Archives of Internal Medicine 155(7), 734-737.
(82) Davila DG, Hurt RD, Offord KP, Harris CD, Shepard JW Jr. 1994. Acute effects of transdermal nicotine on sleep architecture, snoring, and sleep-disordered breathing in nonsmokers. American Journal of Respiratory and Critical Care Medicine 150(2), 469-474.
(83) Ebrahim IO, Shapiro CM, Williams AJ, Fenwick PB. 2013. Alcohol and sleep I: effects on normal sleep. Alcoholism, Clinical and Experimental Research 37(4), 539-549.
​(84) Glass J, Lanctot KL, Herrmann N, Sproule BA, Busto UE. 2005. Sedative hypnotics in older people with insomnia: meta-analysis of risks and benefits. BMJ 331(7526): 1169.

Picture
Proudly powered by Weebly