Sleep: An Evolutionary Imperative. Are You Getting Enough?

INTRODUCTION

Everyone knows that sleep is important. Yet, as a nation, we’re sleeping a full hour less per night on average than we were just ten years ago.(Jean-Louis, Kripke et al. 2000) This trend is certainly not new; for more than 25 years, Americans have been sleeping less and less each night and, in a recent study, up to half of all American adults report having sleep problems in any one year. (Becker 2006) Of all the sleep disorders, insomnia is, by far, the most common, affecting nearly 70 million of us; in a recent sur- vey, 35% of respondents had insomnia every night and nearly 60% reported insomnia at least a few nights per week. Sleep problems have been dubbed “a hallmark of modern living.”(Bollinger, Bollinger et al. 2010)

Why this is happening is not clear. Is it because we often favor work, play, socializing, or learning over sleep? Are we sleeping less because of problems with our local living environ- ment? Are sleep disturbances really a sign of some underlying disease? Is the problem, as many want to suggest, simply stress? While most people do experience some level of stress in their lives, one theory is that it’s a deficiency in positive coping skills, rather than the stress itself, that lets the body veer out of balance and causes sleep problems. Also interesting to note, recent re- search suggests that high positive emotions (not just high nega- tive emotions) can also cause a poor night’s sleep, too.(Baglioni, Spiegelhalder et al. 2010)

Given that so many of us aren’t getting enough high-quality sleep, it is worthwhile to educate ourselves on how sleep or sleep deprivation affects our health. What do scientists know about sleep? Why do we even need to sleep? How many hours of sleep do we really need each night and what happens if we sleep for less than this optimal number? Equipped with answers to these questions, we will be more apt to make healthy choices regarding sleep.

WHAT IS KNOWN ABOUT SLEEP?

What Happens During Sleep & Why Do We Need It?

Sleep may have given humans an evolutionary advantage, pro- ducing immobility at times when activity would be unproductive (preventing wasteful energy expenditure) or dangerous (prevent- ing unnecessary exposure to predators).

Sleep was first described physiologically in the 1930s(Loomis, Harvey et al. 1935) and our understanding was greatly enhanced by the discovery of rapid eye movement (REM) in the 1950s.(Aserinksy and Kleitman 1953) Our sleep is usually divided into various phases, based on the differences in brain activity throughout the night. During these various phases, our bodies repair and our memories are organized.

Current research suggests that the interplay between ho- meostasis and circadian rhythm determines our sleep pattern. Homeostasis, which is the ability of the body to adjust its physi- ology in response to fluctuations in the outside environment and the weather, would have us sleeping in small increments through- out the day to balance our wakeful hours.

Circadian rhythm, on the other hand, is the 24-hour cycle in physiological functioning found in most living organisms. Until recently, it was assumed that the human circadian rhythm was also 24 hours in length. However, there are several curious anomalies to human circadian rhythm for which a clear answer is not yet available. Two unique features of the human circadian system are (1) an internal tendency toward “desynchronization,” in which core body temperature has a cycle of about 25 hours, and (2) a sleep-waking cycle of about 30 hours.(Yamanaka, Honma et al. 2009) While it is now known that exposure to bright light appears to re-synchronize the body to the planetary 24-hour cycle,(Yamanaka, Honma et al. 2009) it is not yet clear why the body’s day/night clock is longer than the duration of one day.

A comparison to simpler organisms is also curious: hu- man beings experience drastic disturbances to our biological clocks with sudden shifts in our daily schedules, leading to sleep disorders, mood disorders, and impaired performance. Honey- bees, on the other hand, do not have this liability and are able to very quickly adjust their own physiological rhythms when they are subjected to drastic changes in their work schedules. It is the complex and highly interactive social environment of the honeybees that help them in making these nimble adjustments. (Shemesh, Eban-Rothschild et al. 2010) Perhaps this tendency for the human nervous system to drift toward desynchronization is the result of having a very well-developed brain; it is analogous to high-performance sports cars, where greater sophistication requires more frequent maintenance and tune-ups.

The Problem Doesn’t Start at Bedtime

One reason a person’s night can become disturbed is because their day is out of balance. If you can’t get to sleep, the problem didn’t begin just at that moment, but can have its roots much further back in time. In the physiology of the body, timing is a critical issue and a person’s misuse of time can lead to loss of coordina- tion between important body functions, a term called chrono- disruption. Whether this chrono-disruption, or “physiological bad timing,” is the result of poor sleep, or can itself cause sleep disorders, is not clear. However, both common sense and the following research data would suggest that conducting oneself contrary to one of nature’s most fundamental cycles of time, the diurnal rhythm (or daytime-nighttime cycles), is probably not a good idea.

The Role of Light

Light plays a key role in our sleep cycle, centered on critical light-receptive cells on the retina of the eye that help regulate not only circadian timing and neuroendocrine function, but also a person’s behavioral responses. When exposed to bright light, those photoreceptive cells stimulate parts of the brain that are not image-forming centers, but serve primarily as the body’s master biological clock. Furthermore, when the retinas are exposed to light much more dim than sunlight (as is most indoor lighting),

this light deficiency causes an information deficiency in the brain that sets in motion a chain-reaction of harmful side-effects in- cluding insomnia, depression, and impaired cognition.(Turner, van Someren et al. 2010) In other words, if you spend most of your daytime hours indoors, you may well be “light deficient.” This daytime light deficiency may be a common cause of night- time sleep disorders.

Recent research from the Institute of Medical Microbiology and Hygiene in Germany provides detailed insights that were first explained by 3rd Century BC medical texts from China: That circadian rhythm is controlled by both central control systems in the brain as well as local/regional cellular centers in other body tissues. For the immune system specifically, the effect of sleep deprivation can be to inhibit immune function by disrupting the circadian rhythms within immune system cells themselves, which in turn may be a long-term consequence of disturbances in hormonal cycles and circadian rhythms. These researchers also suggest that sleep, through the lowering of body temperature, “primes” the cells of the immune system and by doing so provides a timing signal for circadian clocks in the blood cell-producing bone marrow. It is chronic sleep disruption that desynchronizes these different time clocks, which in turn leads to dysregulation of the body’s immune responses.(Bollinger, Bollinger et al. 2010)

Sleep & Learning

One important function of sleep that is of interest to students is that it consolidates or reorganizes memory.(Kopasz, Loessl et al. 2010) Based on the results of three separate meta-analyses of 17 studies conducted by a team in the netherlands, successful learning and school performance are linked to sleep quality, sleep duration, and the absence of daytime sleepiness.(Dewald, Meijer et al. 2010) This means that in order to remember what you stud- ied during the day, you need to get a good night’s sleep at night. Renowned sleep researcher Matthew P. Walker at the University of California at Berkeley has also added important understand- ing to the relationship between sleep and learning; not only does sleep help the brain integrate individual bits of information into broader themes and patterns, it may fundamentally enhance the brain’s capacity for creativity. (Walker, 2009)

NON-REM & REM: THE TWO STATES OF SLEEP

Non-REM Sleep

This is the “deep” phase of sleep, which conserves energy, restores the central nervous system (CnS) or components of the CnS (such as the frontal cortex and glycogen stores), cools the body and the brain, and promotes immune function.(Dement and vaughan 2000)

REM Sleep

This is the more active “rapid-eye-movement” (REM) phase of sleep that helps the mind with psychological and/or emotional adaptation. By virtue of its stimulating effect, REM sleep also promotes development of the central nervous system and compensates for the deep brain stillness and brain cooling that happens during non-REM sleep. Furthermore, REM sleep facilitates periodic awakening to help a person survey their environment.(Dement and vaughan 2000)

SLEEP AND THE IMMUNE SYSTEM

When we get sick, we tend to feel tired and sleep more. But is this coincidental or is sleep a recuperative immune function? One study showed that infected rabbits that slept more had a better prognosis, suggesting that sleep might enhance recovery. But it’s unclear whether other factors, such as stress, might have been the cause of disrupted sleep in the rabbits that didn’t fare so well. (Dement and vaughan 2000)

In humans, there’s an increasing amount of research evi- dence that suggest that the right amount of sleep might prolong life; one study of 185 people aged 60 to 80 found that the quality of their sleep predicted the length of their remaining lifespan. (Dew, Hoch et al. 2003)

As more research is conducted on this subject, it is hoped that the exact nature of the relationship between sleep and the immune system’s role in controlling tumor growth can be ascertained.

GETTING A “GOOD” NIGHT’S SLEEP

What is the Definition of Good Sleep?

What constitutes “good” sleep is highly subjective, but most people would agree that an evening of high quality sleep is one in which you’re able to fall asleep quickly, stay asleep throughout the night, and wake up feeling refreshed. To achieve this sort of sleep, there are several approaches, from behavioral to pharmacological.

Good sleep can be defined in terms of sleep architecture – it is characterized by an optimal length of each sleep stage (which is age and gender specific), an appropriate distribution of sleep stages throughout the night, and a low frequency of arousal from sleep. Good sleep can also be defined in terms of general physi- ological activity; non-REM sleep, which constitutes approxi- mately 80% of sleep in a night (when optimal), is characterized by reduced physiological activity, such as reduced metabolism.

A person’s subjective assessment of their sleep quality and daytime functionality also define their “sleep health.” These tend to correlate well with objective performance estimates of daytime functioning.(Dement and vaughan 2000)

WHAT ARE THE DIFFERENT TYPES OF SLEEP DISORDERS?

Sleep Debt

Homeostasis in the human body dictates that for every two hours of wakefulness, we require one hour of sleep. If sleep cycles become disturbed, we end up “owing” hours of sleep and these hours are our “sleep debt.” Sleep debt is cumulative and carries over from one day to the next. The number of hours of sleep required per day varies with age and with individuals. On average, adults need to sleep eight hours per day, but this decreases with age.(neikrug and Ancoli- Israel 2009) Children and teens require ten hours per day on average.

Chronic Versus Acute Sleep Loss

While chronic sleep loss has been shown to be harmful to well-being, there is growing evidence that the occasional acute sleep disturbance might actually boost the immune system. (Rechtschaffen, Gilliland et al. 1983; Everson 1993; Landis and Whitney 1997)

In a study involving sleep-deprived rats, the animals’ ability to defend against infection was dependent on the length of their sleep deprivation. Evolutionarily, it may be that the immune sys- tem needs to be enhanced by brief total sleep loss, such as when being hunted by a predator. But without sleep, the immune sys- tem does eventually fail.(Dement and vaughan 2000)

WHAT CAUSES OR EXACERBATES POOR SLEEP?

In addition to the obvious causes of poor sleep that are a function of lifestyle and choice, there are many medical problems that can lead to poor sleep, some of which we review here.

Serotonin Dysfunction

A core part of brain function involves the compound serotonin, which is a neurotransmitter that is biochemically derived from the amino acid tryptophan and is critical to the transmission of nerve signals between neurons. The cells which produce this neurotransmitter, although few in number, are essential to the regulation of important brain functions including those that fol- low circadian rhythms: Sleep and waking, thinking, mood, appe- tite, sexual interest, body temperature, and behavioral regulation of aggression and impulse.(Jacob and Fornal 1995) Insufficient production of serotonin has widespread effects on the brain, play- ing a role in insomnia and mood disorders including depression, anxiety, and obsessive compulsive and bipolar disorders.(Davis, Charney et al. 2002)

Chronic Pain & Sleep

While people generally recognize that chronic pain can interfere with sleep,(Wells, Li et al. 2009) new research has shown that the effect goes in both directions, and that sleep disturbance con- tributes to increased pain levels.(Moldofsky 2010)

In people with cancer, there frequently occurs a combination of pain, fatigue, and sleep disturbance. A recent meta-analysis has provided evidence that these symptoms can all be improved by guided imagery/hypnosis and cognitive-behavioral therapy and coping-skills training, relaxation training, meditation training, and music.(Kwekkeboom, Cherwin et al. 2010)

Obstructive Sleep Apnea

In the Wisconsin Sleep Cohort study, which began over 20 years ago and monitors the sleep health of over 3000 people, re- searchers discovered that for every 10 persons, 1 to 2 suffer from untreated sleep apnea.(Young, Palta et al. 2009) Sleep apnea is a breathing problem in which a sleeping person frequently snores, often becoming louder until interrupted by a period of silence in which breathing stops and is then restarted after a loud gasping. This snoring returns often very frequently during the night. The problem stems from anatomical abnormalities in the back of the throat; usually, the body can compensate by the brain’s input to the muscles which dilate the upper airway, but those signals are suppressed during sleep, leading to the collapse of the airway in the throat.(Dempsey, veasey et al. 2010)

It has long been known that the frequent nighttime episodes of lower oxygen levels that result from this airway collapse are linked to sexual problems (erectile dysfunction), cardiovascular problems (heart disease, high cholesterol, stroke, and swelling in the legs), performance deficits (daytime drowsiness, waking up groggy, depression, hyperactivity, insomnia, memory problems, headaches, personality changes, cognitive impairment, and poor concentration), liver disease (liver inflammation and fibrosis), and to an increasingly more common health problem: diabetes. (Zias, Bezwada et al. 2009; Brondel, Romer et al. 2010; Drager, Jun et al. 2010; Eastwood, Malhotra et al. 2010; Tian, Zhang et al. 2010; Tsai 2010)

The relationship of sleep problems to diabetes has been much better understood with recent research. Compared with men, the odds that a woman with sleep apnea developing diabetes are 11 to 1, based on the results of a 16-year follow-up study. (Celen, Hedner et al. 2010) Furthermore, the type of sleep prob- lems a person has can predict their subsequent risk of developing diabetes: sleep of short duration (less than 5 to 6 hours per night), sleep of very long duration (over 8 to 9 hours per night), or dif- ficulty in getting to sleep or maintaining sleep all increase the risk of developing diabetes between 28% and 84% (nearly double). (Cappuccio, D’Elia et al. 2010)

While sleep apnea can sometimes be successfully treated by surgery,(Ye, Liu et al. 2009) there are no clearly established evidence-based guidelines for assessing suitability for surgery as based on a patient’s degree of airway obstruction and the likeli- hood of receiving surgery depends on the level of clinician expe- rience and resources available at individual hospitals.(Georgalas, Garas et al. 2010)

Although not widely used by sleep medicine centers, it has been known for the past 15 years by Japanese researchers that abnormal positioning of the jaw during sleep (too far to the back) can cause sleep apnea.(Masumi, nishigawa et al. 1996; Smith 1996) Continued research on this discovery in Japan, China, Italy, and the US has led to the development of small splints that can be inserted into the jaw, helping move the jaw forward and opening up the airway at the back of the throat to allow for better air passage during sleep. Besides improving sleep, this also helps correct the heart rate abnormalities caused by sleep apnea.(Smith 1996; villa, Bernkopf et al. 2002; Coru- zzi, Gualerzi et al. 2006; Arai, nakayama et al. 2007; Tsuda, Tsuda et al. 2007; Zeng and Gao 2009) Dentists who have special training can use an x-ray examination of the skull and jaw to identify whether or not a patient is likely to benefit from a splint(Monteith 2004) and can also provide special exercises that a patient can perform to improve jaw positioning.(Ueda, Almeida et al. 2009)

In people not helped by the splint or exercises, sleep apnea can still be successfully treated by a device called C-PAP, which blows air at a prescribed pressure through a mask worn during sleep, helping keep the airway open. Although awkward and unsexy, the devices can still be effective. A new oral device based on the splint, called OPAP, was tested at Stanford University for use in combination with C-PAP and recently received FDA approval (more information available at opaphealthcare.com).

Although overnight evaluation and treatment at clinical sleep centers can be helpful in treating obstructive sleep apnea, it is nevertheless a daunting (and expensive) process. Encour- agingly, researchers at the University of Saskatchewan this year published an excellent clinical study demonstrating that at-home diagnosis and treatment using a take-home device was just as good as that same procedure being done at a sleep center. This equivalence was demonstrated in terms of outcomes in sleepiness scores, sleep quality, quality of life, blood pressure, and compliance in the use of the CPAP device.(Skomro, Gjevre et al. 2010)

Hepatitis C

A wide range of other physical ailments can also cause sleep prob- lems. In hepatitis C, up to 60% of patients will experience newly diagnosed sleep problems, which is encouragingly reduced to 30% of patients who undergo treatment with interferon.(Socka- lingam, Abbey et al. 2010)

Cancer

It is known that anxiety and sleep problems can follow a cancer diagnosis.(Price, Zachariae et al. 2009; Savard, villa et al. 2009) It can also work in the other direction: sleep problems (and the resulting disturbances in day/night variations of melatonin levels in the blood) can predate diagnoses of breast and prostate cancer by many years. new research from Case Western Reserve University has found that sleeping less than 6 hours per night increases the risk of colon cancer by nearly 50%.(Thompson, Larkin et al. 2010) Additionally, in a large- scale survey of 363 people newly diagnosed with breast cancer, researchers found that compared to age-matched controls, those diagnosed were 40% more likely to have reported keep- ing lights on while sleeping, 40% more likely to sleep during the daytime, and 20% more likely to regularly close the win- dow shades while sleeping at night. These results, while not statistically significant, nevertheless suggest a plausible theory. (Li, Zheng et al. 2010)

Hospitals

As the intention in going to a hospital is usually to get better, it is ironic that the noise levels in most hospitals can interfere with pa- tients’ sleep, particularly in intensive care units.(xie, Kang et al. 2009) This is especially problematic in that poor sleep is associ- ated with poor intensive care unit medical outcomes.(Weinhouse, Schwab et al. 2009; Weinhouse and Watson 2009)

WHAT ARE THE CONSEQUENCES OF NOT SLEEPING WELL?

Your Own Safety and the Safety of Others

A curious anomaly in human performance is that people often overestimate their own abilities to perform critical tasks, such as driving. Most people also misjudge their level of sleepiness and amount of sleep debt and are usually wrong about how likely they will fall asleep in the near future, which leads people to think they’re alert enough to drive when they really aren’t. Unfortunately, sleepiness behind the wheel is a major cause of fatal crashes(Abe, Komada et al. 2010; Sagaspe, Taillard et al. 2010; valent, Di Bartolomeo et al. 2010; vennelle, Engleman et al. 2010) and people with sleep apnea are six times more likely to have traffic accidents than those people without this problem. (volna and Sonka 2006) And when you add alcohol to the mix, combining even a small amount of alcohol while you’re already tired is the functional equivalent of having a lot of alcohol when you’re well-rested.(Rodenstein 2009)

Medical Errors

Researchers at the Institute of Medicine, an independent federal research agency, recently published a comprehensive report in which they found that the frequency of serious medical errors goes up when medical residents are deprived of sleep. Medical residents are physicians who have graduated from medical schools, but are practicing medicine in a hospital or clinic under the supervision of fully licensed physicians. Almost all hospital stays involve being cared for by a medical resident at some point.

The problem involving medical errors centers around the difference between being awake and being competently alert. It is possible to use stress (adrenaline), exercise, and caffeine or other stimulant drugs to stay awake. It is not possible, however, to use these stimulants to overcome the damaging impact of sleep depri- vation on job performance and judgment.(Czeisler 2009) In this way, medical personnel being underslept leads directly to medical errors because of impaired skill and judgement.

This poses numerous ethical dilemmas for hospitals. Should hospitals limit physicians’ work hours to protect patient safety? Because sleep disorders increase substantially with age, should medical personnel be tested for suitability for long work shifts over the course of their careers?(Czeisler 2009)

Resident physicians at US hospitals are allowed to work for up to 30 hours in one shift. (Olson, Drage et al. 2009) Two-thirds of medical residents report that “sleep loss and fatigue have a major impact on my personal life” and nearly half report that “sleep loss and fatigue have a major impact on my work.”(Rosen, Gimotty et al. 2006) The number of medi- cal errors that can result from these working conditions are, not surprisingly, quite high. For example, in a survey of 254 internal medicine resident physicians, 41% reported that their own fatigue directly caused the most serious medical error they had made, and that a third of these errors led to the death of a patient.(Wu, Folkman et al. 1991)

Lurking beneath these issues of human performance are the financial incentives for hospitals, which depend on the profit mar- gin between payments they receive from Medicare or third party insurers and the low wages they pay to their resident physicians- in-training.

Emotional & Psychiatric Health

Mood disorders, anxiety, dementia, emotional instability, and the use of antidepressant medications, are all associated with sleep disorders. In many of these disorders, it is not yet known which came first: the sleep problem or the psychiatric problem.(Diekel- mann, Wilhelm et al. 2009; Sateia 2009; Teman, Tippmann- Peikert et al. 2009)

Lack of Sleep May Lead to Overeating

In a study published March 2010 in the American Journal of Clinical nutrition, researchers reported, “sleep restriction could be one of the environmental factors that contribute to the obe- sity epidemic.” They closely followed the eating, sleeping, exer- cise, and eating activities of 12 healthy young men during two 48-hour periods. The researchers first observed those men for a two-day “baseline” or control period. They then followed them closely for an active two-day study period. On the first day, the men in the study were asked to go to bed at 12 am and wake up at 8 am; on the second day, they went to bed at 2 am and woke up at 6 am. What the researchers found was that after sleeping only four hours, the men in the study ate an average of 22% (or over 500) more calories per day than they did after eight hours of sleep.

HOW TO SLEEP BETTER: UNDERSTANDING OUR NEEDS AND PATTERNS

The first step to better sleep is to determine your sleep needs and circadian pattern. This can be accomplished by keeping notes on the times when you are at peak alertness during the day. These peaks in alertness are ideal times for tackling your most challeng- ing tasks. During troughs in alertness are appropriate times for napping, resting, not driving, and other inconsequential tasks. Having then determined those optimal cycles, you can then make choices that help you lead a lifestyle that respects your body’s natural sleep patterns.

Treat sleep like exercise and diet. It is essential to pay atten- tion to it and manage it for the sake of health and longevity.

Sleep Clinics

A website sponsored by the American Academy of Sleep Medi- cine provides a list of sleep clinics. This site can be searched geo- graphically and is available at www.sleepcenters.org.

Music

A recent study from researchers in Taiwan found that people who listened to soft, slow music at bed time “experienced physical changes that aided restful sleep, such as lower heart and respira- tory rates.” Participants listened to 45-minute relaxing music tapes at bedtime for three weeks. The study found that this resulted in “significantly better sleep quality” and that “sleep improved weekly, indicating a cumulative dose effect.” (Lai and Good 2005)

Yoga

A recent study showed that participants who attended regular yoga sessions reported “significantly lower sleep disturbance” as com- pared to a control group. In this study, the benefits of yoga included better quality of sleep, the ability to fall asleep quicker, longer sleep duration, and less use of sleep medications. (Cohen 2004)

SLEEP HYGIENE TIPS

SLEEP ONLY WHEN SLEEPY
This reduces the time you’re awake in bed. If you can’t fall asleep within 20 minutes, get up and do something boring until you feel sleepy. Avoid bright light during this time.

DON’T TAKE NAPS
This will help make you tired at bedtime. If you must nap, sleep for less than an hour before 3pm.

GO TO BED ON TIME
Get up and go to bed the same time every day, even on weekends. It’s easier to sleep when you have a regular sleep cycle.

TIME YOUR EXERCISE
Regular exercise can help improve your sleep, but don’t do so too close to bedtime (at least 4 hours).

DEVELOP SLEEP RITUALS
It is important to give your body cues that it is time to sleep, such as listening to relaxing music, drinking herbal tea, or meditating.

ONLY USE YOUR BED FOR SLEEPING
Refrain from using your bed to watch TV, pay bills, do work, or read.

AVOID CAFFEINE, NICOTINE, AND ALCOHOL
Caffeine and nicotine are stimulants and alcohol can cause poor, fragmented sleep. Avoid them all for at least 4 hours
before bedtime.

HAVE A LIGHT SNACK BEFORE BED
Sleeping on too empty or too full a stomach can interfere with sleep, but eat your last heavy meal at least 3 hours before bedtime.

TAKE A HOT BATH
While a hot bath 90 minutes before bedtime will initially raise your body temperature, the subsequent drop in temperature afterwards may make you feel sleepy.

COOL YOUR ROOM
Sleeping in too hot an environment can be difficult. A cooler room, at a sleep-promoting 65 degrees with enough blankets to stay warm, is recommended.

KEEP THINGS DARK AND QUIET
Blackout shades or an eye mask can help block out light and earplugs or a white noise machine can help reduce noise.

RESET YOUR BIOLOGICAL CLOCK
As soon as you get up in the morning, go outside and turn your face to the sun for 15 minutes.

WHAT ABOUT WORKING NIGHT SHIFTS?

European researchers have done extensive research on the effect of shift-work (defined as work at times other than the normal 9 to 5 work schedule) and found that the people whose sleep is impacted most by their work hours are those who work nights and early-mornings as well as those who work slowly backward- rotating shifts (as compared to rapidly forward-rotating shifts). (Sallinen and Kecklund 2010)

PHARMACOLOGICAL APPROACHES

Melatonin

Melatonin was first isolated roughly 50 years ago(Lerner, Case et al. 1960) and is a chemical that has been functionally linked to the body’s regulation of circadian(Malpaux, Migaud et al. 2001; Malpaux, Tricoire et al. 2002) and seasonal rhythms,(Reiter 1993) immune function,(Guerrero and Reiter 2002) and tumor inhibition.(Blask, Dauchy et al. 2002; Blask, Sauer et al. 2002) Melatonin is not a hypnotic or soporific but rather seems to func- tion as a chemical that “opens the gate” to sleep, not something that induces sleep itself.(Kennaway and Wright 2002)

Melatonin production takes place in the brain and is mostly regulated by ambient light; only during darkness does the major- ity of melatonin production take place. The amount of melatonin an individual produces is also genetically determined, but age can also be a factor as people tend to produce less melatonin as they grow older.

Melatonin: Timing Is Everything

Researchers have revealed a substantial body of evidence on how melatonin influences sleep. That some of this information is conflicting suggests that the full story is not yet fully understood. Medicine is a work in progress and new research in the next few years should help fill in some of the gaps in knowledge on this important topic.

Melatonin has been shown to “open the gates” to sleep, so timing is very important depending on the desired effect.

IN GENERAL
Bright light exposure after darkness should be avoided since it disrupts the melatonin rhythm and alters the circadian clock. When used for night-time sleep pro- motion, melatonin is best taken 30 minutes before desired sleep onset.

WHEN TAKEN AT DUSK
Melatonin advances the internal clock, making you feel like it’s later than it really is.

WHEN TAKEN EARLY AT DAWN
Melatonin delays the internal clock, making you feel like it’s earlier than it really is.

TAKIN MELATONIN WHEN TRAVELING EAST
If you were traveling from san Francisco to Paris, take melatonin at dusk san Francisco time (which may be on the plane). Then take melatonin at dusk Paris time when you’ve arrived. a day or so before head- ing home, take melatonin at dusk Paris time and then, once home, at dusk san Francisco time.

TAKING MELATONIN WHEN TRAVELING WEST
If you were traveling from san Francisco to Beijing, take melatonin once you arrive at dusk Beijing time. Before you leave, take melatonin at dusk Beijing time and then, once home, at dusk san Francisco time. note: it has been suggested that westbound travel causes less jetlag. also, it has been suggested that melatonin is not very effective for westbound travel of less than four time zones.

Source: Reiter 2003

Tryptophan

Dietary tryptophan, which can cross the blood-brain barrier,(Young and Gauthier 1981) is a precursor to serotonin production in the brain. The levels of serotonin in the brain can be increased by up to two-fold with a dose of tryptophan of 3,000 mg,(Young and Gauthier 1981), which is an amount capable of improving mood and cognitive function, reducing anxiety, and helping to achieve better sleep. Tryptophan achieves this by increasing the release of melatonin. Melatonin helps facilitate restful sleep, shortening the time it takes to get to sleep, increas- ing average duration of sleep, and improving sleep quality.(Shell, Bullias et al. 2010; Silber and Schmitt 2010)

Although its reputation was marred by a single manufacturing malfunction that caused serious medical problems in a small group of people back in the mid-1990s, tryptophan is now back on the market and is backed by numerous studies supporting its benefits. Because it is a mild sedative, tryptophan, like other sleep medications, can reduce reaction time.(Silber and Schmitt 2010)

Post-thanksgiving Drowsiness: It’s how much you eat, not the turkey

While many people think it’s the tryptophan in turkey that makes people sleepy at Thanksgiving, the real culprit that leads to drowsiness may really just be the overeating that comes with this high- calorie meal. it’s been known for over 60 years that the tryptophan content of turkey is similar to both other meats in general and other poultry in particular.(greenhut, Potter et al. 1947)

Tryptophan is found in nearly all protein-based foods as well as many vegetables. it is abundant in dairy products (milk, yogurt, cottage cheese), sweets (chocolate, dried dates), grains (oats) and meats (red meat, eggs, fish, poultry), nuts and seeds (sesame, sunflower seeds, pumpkin seeds, and peanuts), and legumes (chickpeas, soybeans). among the foods with the highest amounts are eggwhites, atlantic cod, and spirulina.

Prescription Drugs

One of the fastest growing segments of the prescription drug market are sleep aids. These drugs are generally effective in making it easier to fall asleep, stay asleep, and increase total time asleep. There are, however, adverse affects, such as dependency, withdrawal, and tolerance. The World Health Organization broadly defines dependence as “the state of needing or depending on something or someone for support or to function or survive,” and as applied specifically to alcohol and other drugs, “a need for repeated doses of the drug to feel good or to avoid feeling bad.” Withdrawal symptoms are generally defined as those that start after a drug is discontinued or reduced (i.e. symptoms not present before treatment). Tolerance is defined as a decrease in a drug’s effect with continued administration, which results in the need to increase the dose of the drug.(World Health Organization 2010)

not all users of hypnotics become dependent, tolerant, or expe- rience withdrawal. There are various strategies, such as intermittent use, that can minimize adverse effects. It’s important to evaluate the potential benefits and risks with your doctor before beginning any prescription sleep drug program. However, because many sleep-aid drugs can cause side-effects, it’s worthwhile to improve sleep hygiene and work with other exercise, relaxation, or natural medicine ap- proaches before going the sleep medication route.

PUTTING IT ALL TOGETHER

Several key points emerge from our systematic review of the re- search on human sleep patterns:

» Sleep is essential to health. Optimal functioning of almost every body system requires sleep.

» The body needs to be re-synchronized on a daily basis through food, exercise, and face-to-face interaction with other peo- ple. Benjamin Franklin’s saying, “early to bed, early to rise…”, and what your grandmother told you about frequent exercise and regu- lar mealtimes are all true and supported by very recent research.

» Prescription medications, while helpful on an occasional or short-term basis, can have unwanted consequences that include the “rebound effect,” where sleep becomes worse after stopping the use of medication.

» Avoiding information overload is helpful, particularly in the evening.

» Helping the body get in the right mood for sleep is essen- tial, like an airplane taking the proper approach to landing.

» Sleep is a body function most people can’t consciously con- trol, but the way you treat yourself during the day can have a direct impact on whether your body can achieve good sleep at night.

REFERENCES

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