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Feb-09-2014

Sleep Is Anabolic

Sleep Is Anabolic

 

There are a lot of factors that impact on strength, athletic performance, and body composition including the two that are uppermost in most of our minds, the right kind of training and nutrition. While training and nutrition are important, they’re not going to do much for your body composition if your body’s not in a position to make the best use of them.

 

That’s where getting the proper amount of sleep comes in.

 

Why Do We Need Sleep

 

Sleep is essential for survival. Just as we can’t do without food and water, we can’t do without sleep. As with our diets, the quality and quantity of sleep is important to optimal health and functioning.

 

It’s obvious that sleep refreshes us at every level - molecular, genetic, tissue, and everything in between. It also allows the body to repair, replenish, and get its physical and mental processes in order after the ravages of the waking hours. Not getting enough sleep thus impacts on your health and prevents you from fully reaching your body composition and performance potential.

 

As well, even if you get the proper amount of sleep, there are things you can do to maximize the anabolic effects of sleep such as enhancing the anabolic and minimizing the catabolic hormones, increasing protein synthesis at a time when protein catabolism is the norm, and improving recovery from exercise. See http://www.mauromd.com/det-articles-10-Grow-While-You-Sleep----Nighttime-Nutrition.php .

 

 

Stages of Sleep

 

The central feature of sleep is an alteration in brain function that’s associated with changes in the rest of our bodies. Just what effects the alterations and changes have on us both physically and mentally are still topics of intensive investigations.

 

There are two types of sleep in humans and these are described as differences in the frequency and amplitude of brain (EEG) waves. In healthy adult human non-rapid eye movement or NREM sleep (made up of 4 stages ranging from light sleep to slow wave sleep (SWS) or deep sleep phases), and rapid eye movement or REM (dreaming phase) sleep succeed each other in 90-110 min intervals.

 

The general consensus is that SWS is involved in restorative functions and that REM sleep is involved in information processing.[1]However, recent studies show that it’s not that simple.[2]

 

The graphical presentation below shows the typical sleep cycles as most people understand them. Each sleep cycle in this representation is roughly 120 minutes.

 


 (Source: Vincent W. Hevern, Le Moyne College)

 

This ultradian pattern of NREM/REM succession is cyclical, although the amount of time spent in each phase may vary throughout the night. Early in the night light sleep alternates with SWS sleep while later on light sleep alternates mainly with REM sleep. This cyclical pattern may have its roots in danger detection throughout the night and thus is felt to have survival value.[3]

 

The alternation of phases can be influenced by a variety of factors, including age and gender..[4][5]

 

Problems Sleeping Can Be Counter Productive

 

Recent research has given us new insights into the regulation of sleep and wakefulness and how this regulation might relate to energy homeostasis, the control of hunger and satiety, and body composition.[6][7]

 

We know that the amount of energy we have and the amount of exertion we can put out is strictly limited. And if we don’t “recharge” adequately at night we won’t have our full complement to be used during the day.

 

Chronic sleep loss causes excessive sleepiness and decreased mental and physical performance. It also has a negative effect on mood, autonomic and immune functions and increases the risk of physical and mental health problems.[8],[9],[10]These effects by themselves, by increasing our risk of getting viral and bacterial infections,[11],[12]and other health problems, are enough that they would impact on your ability to train effectively.

 

For example recent studies have found that not getting enough sleep can lead to higher risk of high blood pressure, strokes, heart attacks, diabetes, and obesity.[13],[14],[15],[16]A new study found that sleep deprivation increases the risk for colon cancer.[17]

 

But that’s not all. Sleep deprivation has also been shown to affect multiple hormones, and growth and other factors that are counter productive for those wanting to improve body composition and lose body fat, including decreasing levels of thyroid, testosterone, growth hormone, insulin-like growth factor I (IGF-I) and leptin, and increasing insulin resistance, and increasing levels of ghrelin and the catabolic hormone cortisol.[18][19],[20],[21].[22]

 

For example, sleep deprivation adversely affects testicular function and this leads to lower levels of serum testosterone in the body.[23],[24]. Cortisol impairs sleep. In healthy young and old subjects cortisol (and IL-6) plasma concentrations were positively associated with total wake time and negatively with rapid eye movement (REM – dreaming phase) sleep; and in turn, insomnia is associated with an overall increase in ACTH and cortisol secretion.[25]

 

Sleep deprivation disturbs the levels and effects of ghrelin and leptin.[26]While the details and specific effects on both of these hormones has yet to be fully detailed,[27]it’s a sure bet that the changes in their levels and interplay has profound effects on fat metabolism.

 

While the specifics of ghrelin regulation and functions are still being worked out, it is know that it is involved in sleep regulation, increases food intake in both rodents and humans, and conserves fat by reducing fat utilization.[28][29][30]It would appear that the result of increased levels of ghrelin is an increase in appetite, body weight and body fat.

 

In contrast to ghrelin, leptin, which is reduced in sleep deprivation,[31]is an anorexigenic (decreases appetite) factor[32]and it is thought that ghrelin and leptin regulate the energy balance in a reciprocal fashion.

 

Several studies have found that sleep deprivation is a risk factor for obesity and for insulin resistance and diabetes.[33],[34],[35],[36]The most recent study published in October, 2012 in the Annals of Internal Medicine and an earlier one published in the same journal found that after four nights of sleep restriction insulin sensitivity decreased by up to 30 percent, impacting negatively on fat cell lipolysis – making it harder to lose body fat. [37],[38]

 

One study looked at the effects of sleep duration on body weight and metabolism.[39]The authors concluded that in persons sleeping less than eight hours increased BMI and obesity was proportional to decreased sleep. Several other studies have backed up these claims.[40]

 

A recent paper summarized the metabolic and endocrine effects of sleep deprivation as follows:[41]

Besides affecting body composition (weight, fat and muscle mass), other studies have shown that sleep deprivation can adversely affect power and endurance performance in athletes.[42],[43],[44],[45],[46]

 

A more recent study (Leproult R, Van Cauter E. Effect of 1 Week of Sleep Restriction on Testosterone Levels in Young Healthy Men JAMA. 2011;305(21):2173-2174.) investigated the effect of 1 week of sleep restriction on testosterone levels in young healthy men and found that the effects of sleep loss on testosterone levels were apparent after the one week of 5 hours of sleep nightly. At the end of the week their testosterone levels decreased by 10% to 15%, as did their mood and vigor levels, which declined as their testosterone levels declined.

 

Since most testosterone release occurs when we sleep, it makes sense that anything that disturbs sleep, whether it be shift work, disturbed sleep for other reasons, decreasing sleep time on purpose, sleep apnea, etc. would also affect testosterone secretion. As such, as in the elderly, disturbed sleep patterns result in lower morning testosterone levels and all that that implies, including sexual behaviour, body composition, strength and athletic performance, energy levels, and well being.

 

A recent study found that testosterone levels suffer when fathers sleep close to their children.[47]The study intimated that the closeness of fathers to their children lowered their testosterone levels and thus made them better parents since fathers' testosterone levels have been associated with parenting behavior.

 

Perhaps it’s not the closeness of the sleeping arrangement but the fact that sleeping with kids, or anyone for that matter, over the long term results in some mild sleep deprivation simply from having another body or bodies sleep/wake patterns interrupting your sleep.

 

Sleep deprivation also has other negative hormonal effects besides increasing the catabolic hormone cortisol and decreasing testosterone. For example,

levels of Insulin-like Growth Factor 1 (IGF-1), a hormone with anabolic properties that is secreted in response to growth hormone, are rapidly reduced under conditions of sleep deprivation, and on the opposite end myostatin levels are increased, imparing muscle hypertrophy.

(Dattilo M, Antunes HK, Medeiros A, Mônico Neto M, Souza HS, Tufik S, de Mello MT. Sleep and muscle recovery: endocrinological and molecular basis for a new and promising hypothesis. Med Hypotheses. 2011 Aug;77(2):220-2.)

 

As well, sleep deprivation has negative effects on the immune system (Axelsson J, Rehman JU, Akerstedt T, Ekman R, Miller GE, Höglund CO, Lekander M. Effects of sustained sleep restriction on mitogen-stimulated cytokines, chemokines and T helper 1/ T helper 2 balance in humans.PLoS One. 2013 Dec 11;8(12)).

 

The bottom line is that sleep deprivation results in negative hormonal changes that impact on your ability to maximize body composition and performance, even if your training and diet are up to par.

 

How Much Sleep Do You Need?

 

Because it varies it’s important to find out what is enough for you. For most of us it’s between 7 and 9 hours of relatively uninterrupted sleep. Sleeping more than 9 hours on a regular basis tends to also be unhealthy and lead to similar problems as not getting enough sleep.[48]

 

We can achieve the amount of sleep we need straight through at night or with 6-8 hours at night supplemented by a nap in the afternoon (see below under Siesta).

 

The amount of sleep you need may also depend on your training. For example, you may want to sleep more after a heavy training session to increase recuperation. Not getting enough sleep when you’re training hard is counter productive.

 

Over the last five decades I’ve had personal experience with how lack of sleep can affect your body composition, strength and performance.

 

In training for powerlifting competions I’d often run into a wall where no matter how hard I trained or how well I ate, I just wasn’t getting anywhere. The first time it really hit home was when I was interning. I was stressed out and sleep deprived for a few months straight during which nothing went right as far as my training. In fact even though I still trained hard and ate well (and no I didn’t eat much of the hospital food, which at that time was pretty horrific) I was going backward.

 

I then changed to a ward where there really wasn’t a lot to do so I was under less stress and able to get a full night’s sleep. In fact things were so lax that I didn’t even use an alarm clock to wake up. I woke up whenever I woke up.

 

Lo and behold, without changing my diet and training appreciably, I began to get stronger, put on some muscle and get leaner at the same time. Even the people around me noticed and began to wonder what anabolics I was using.

 

It turns out the anabolics were my own, uncovered as I reversed the negative hormonal changes that occurred secondary to my sleep deprivation.

 

The lesson learned was my performance and body composition depended not just on my training and diet, but on my ability to get enough sleep to allow my body to recuperate and to keep my hormonal status positive.

 

And it was a lesson well learned since it’s allowed me to keep in tune with my body so as to maximize the effects of my training and diet, and has allowed me to counsel people about one of the things that might be wrong when they ask me why they’re not getting what they should from their training and diet. 


Getting a Good Night’s Sleep

 

For most of us just getting to bed earlier will insure that we get a reasonable night’s sleep. However, for one reason or another, some people may find it difficult to get to sleep, have difficulty staying asleep, or wake up too early.

 

My usual advice to patients who are having problems sleeping is as follows:  

On the nutrition side, it’s a good idea to use a good multivitamin/mineral supplement to make sure you’re not running into any marginal deficiencies that might affect your sleep. Choose one with more than the RDA of the B vitamins, and a good amount of metabolically active B12 (methylcobalamin is the best – avoid the synthetic cyanacobalamin in you can).

 

Increase your dietary and supplemental calcium and magnesium since even though there no real proof, some people feel that they will help you get a better sleep. For those that find dairy products help it could also be the L-tryptophan intake with dairy products that also helps. 

 

What To Do When You Can't Sleep

 

For some the simple measures I’ve outlined above just don’t work. At that point you may have a sleep disturbance that needs to be dealt with. I often tell people that having the occasional sleeping problem is nothing to worry about. The important factors to consider are duration and severity:

 

How long has it been going on? Does it interfere with your daily functioning? Most sleep researchers agree that people develop insomnia from a tangled interplay of psychological, emotional, biological, medical, and environmental factors. It is important to remember that insomnia is not a disease, but a symptom of a problem.

 

We've all had an occasional bad night, when we can't stop our minds from racing, or we're sick with a cold or a have some aches and pains. This occasional insomnia is annoying but not too serious and usually lasts no more than a few nights or, at most, a few weeks. It can be triggered by almost anything that upsets our status quo including relationship problems, jet lag or almost any other physical or emotional stress. This "acute" insomnia is self limiting and effectively treated by making some changes in your lifestyle and if need be by the use of over the counter medications.

 

Ongoing psychological stress, such as bereavement, divorce, or relocation can result in longer periods of insomnia that may be more troublesome. Chronic insomnia is usually defined as lasting more than three weeks and can last for months or years. Both these types of insomnia are more serious and should be treated with the help of your physician who can help you sort out and if necessary treat your sleeping problem.

 

According to national statistics, at least one half of all instances of insomnia are caused by psychological problems. Waking up too early is common for people who are depressed, and difficulty falling asleep is often caused by anxiety. Medical causes, such as chemical imbalances, hormone upsets, infections, allergies, arthritis, pain, headaches, and coughing can cause you to sleep poorly. Insomnia is a side effect of many medications. Alcohol and drug addiction can also interfere with sleep.

 

Your doctor and if needed sleep professionals, can suggest the best way to deal with your sleeping problems including medications for stress and depression and any diseases, biofeedback, stress management, psychotherapy, sleep hygiene techniques, and referral to sleep clinicians and clinics.[55],[56]

 

As science gains a new understanding of sleep, your doctor has more weapons than ever to tame insomnia. And with these new weapons, physicians are employing a more aggressive "nip it in the bud" plan of attack. When your sleep schedule is seriously thrown out of whack, doctors now realize, it's vital that you get it back in synch right away.

 

Sleep Aids

 

For those of us with the occasional common garden variety, can't shut the mind off type of insomnia, when your body refuses to sleep, over-the-counter nighttime sleep-aids, containing antihistamines and/or herbal products are a viable option. Used appropriately, these sleep-aids can help provide a better, sounder sleep and get you through short term sleeping problems.

 

Most of the herbal preparations and even the antihistamines won’t interfere with natural sleep cycles or leave you groggy in the morning.[57]If they do you should either decrease the amount you’re taking or change to something else.

 

Certain herbs have been used to improve sleeping problems. Among these are valerian root, St. John's wort, skullcap, passionflower, chamomile, Jamaican Dogwood, Siberian ginseng, hyssop peppermint and devil's claw root.

 

Valerian

 

Although there is little information on most of these herbs and their effects on sleep, valerian has been shown to be an effective mild sleeping aid that generally allows people to fall asleep faster and get a better nights sleep without morning drowsiness.[58],[59]Valerian root contains two substances of pharmacologic interest: valepotriates and sesquiterpenes. Both substances have sedative effects.

 

As well, valerian has been found to be useful to improve sleep in those who are in withdrawal after the use of prescription sleeping pills.[60]

 

Besides the herbs there are other safe and effective sleeping aids including kava root, melatonin and tryptophan. In the various studies on these compounds, and in my experience, the occurrences of adverse effects are rare if used in appropriate doses.

 

Kava

 

Kava is made from the root of the pepper plant, Piper mesthysicum, found in Polynesia, Melanesia, and Micronesia. A number of compounds referred to as kava pyrones (kawain, dihydrokawain, methysticin, and dihydromethysticin) are thought to be responsible for kava-kava's sedative effects. It is used by many as a remedy for stress and restlessness, and is useful as a hypnotic (sleeping aid).[61],[62],[63]

 

Kava was restricted for use in 2002 in Europe, United Kingdom and Canada over concerns it may cause liver problems, although the cause was likely due, in part, to companies using chemical extracts from poor quality material using an incorrect type of Kava.

 

However, a recent paper suggested a six-point plan for kava standardization that would make the use of kava safe as well as effective.[64]

 

The six-point framework outlined in this paper for the safe production and use of Kava is as follows;

  1. Use of Kava plants at least five years old ("noble" type of Kava cultivar is preferred, as it is traditionally considered safe)
  2. Use of the peeled rhizome (root) of Kava plant (not leaves or aerial parts)
  3. Water-soluble extract for Kava (not alcohol or chemical solution to extract constituents)
  4. Dosage recommendations of less than 250 mg of kavalactones (the active chemicals) per day for medicinal use
  5. Systematic rigorous future research investigating safety issues (potentially from poorly stored and manufactured Kava material, and/or incorrect cultivar and plant material), and human clinical trials using noble cultivars prepared via good pharmaceutical manufacturing practice
  6. A Pan-Pacific quality control system enforced by strict policing. 

L-Tryptophan

 

L-Tryptophan is a naturally occurring amino acid that is used for the production of serotonin and melatonin, two vital brain chemicals necessary for sleep and mood regulation.

 

L- Tryptophan supplements were unavailable for several years due to safety concerns arising from a contaminated batch produced in Japan. It’s now available again. For those that don’t want to use L-tryptophan, 5-hydroxytryptophan, the immediate precursor to tryptophan, is an effective substitute.

 

L-Tryptophan rich foods or L-tryptophan supplements before bed can help insure restful sleep.[65]The best sources of tryptophan are turkey, milk, tuna, eggs, fish, almonds, bananas or peanut butter. Important co-factors (things to take with the tryptophan to aid its utilization) are Vitamins B3, B6, C and magnesium.

 

Melatonin

 

Melatonin can be useful as a sleeping aid especially in older people. The pineal gland normally secretes the highest levels of melatonin at night, when most people sleep. However, melatonin production decreases dramatically with age, and may contribute to the increasing sleeping problems most people encounter as they age. A small dose of melatonin taken before bed is cleared by the next morning, although long term use may result in storage in fat tissue.

 

A recent study found that melatonin primes sleep-associated brain activation patterns in anticipation of sleep[66]and as such can be useful in mild insomnia. The study found that the effects of melatonin on sleep were felt about 2 hours after endogenous melatonin production. I would suspect the same 2 hours would be needed after taking melatonin supplements.

 

In recent years melatonin has been shown to have other beneficial effects due to its antioxidant, anti-inflammatory, and other actions.[67],[68]

 

Some people find a combination of L-tryptophan and melatonin taken a few hours before bedtime extremely effective for times when getting to sleep is a problem because of something stressful that’s happening in your life.

 

An interesting tidbit in the press lately is that the light emitted by tablets, for example the iPads, and cell phones if used in the bedroom can decrease melatonin production and thus interfere with sleep. Maybe and maybe not. But for sure getting all wound up just before going to bed isn’t going to help.

 

A Note of Caution

 

People using these sleeping aids on their own, however, should be wary about using them for prolonged periods of time. If their sleeplessness continues for more than two weeks they should see their doctors because persistent insomnia may be a symptom of an underlying problem or illness.

 

And if self-help and the usual medical care fail, insomniacs can call on sleep centers for treatment. These centers have experts such as neurologists, psychiatrists, and pulmonary specialists working as a team to diagnose and treat the causes of insomnia.

 

The bottom line is that you don't have to suffer through sleepless nights. By taking an approach such as I've outlined above you can solve your sleep problems and reap the benefits from having both good nights and days. 

 

The Siesta

 

Daytime naps, usually lasting from a few minutes to a few hours, are a mainstay of some countries, and in others it’s practiced by a large part of the population. For example, in 2005, a survey found that 55% of the respondents napped once a week and 35% napped  two or more times a week.[69]

 

Why we nap has yet to be worked out but for most nappers it obviously serves a biological purpose. For some if may be related to disturbed sleep at night, secondary to some problem such as sleep apnea.[70]However, in my opinion, these are in the minority. For the rest of us naps help relieve symptoms of physical and mental fatigue and stress.

 

The pros and cons of daytime naps are still being debated with no real solid consensus. Some believe that any napping will affect the quality of sleep at night and as such should be avoided. It appears, however, that napping may not affect sleep at night.[71]

 

For example, in healthy adults aged 55-85 years an opportunity to nap for 2 hours in the afternoon did not influence the duration or quality of subsequent nighttime sleep so that the 24-h total sleep time was increased.[72]A nap was associated with improved cognitive and psychomotor performance after the nap and throughout the next day.

 

Others that napping a few hours is counter productive as far as productivity and quality of life.

 

Others feel that naps are healthy and productive, and don’t interfere with sleep as long as they’re not longer than 30 minutes. While still others feel that naps should be at least an hour and a half to two hours long so as to involve the deep sleep cycle, which is the cycle that invokes the anabolic, hormonal environment mentioned above.

 

A recent review[73]concluded:

 

“Daytime naps can promote wakefulness and health. The restorative effects of a daytime nap are well recognized and are supported by scientific evidence. Longer and frequent naps during the day could have adverse long-term health consequences; however, individuals requiring such naps probably have an unrecognized sleep disorder or are sleep deprived for other reasons. The art of napping is in restricting the duration of naps to less than 30 min each day, as short naps appear to be especially beneficial. Training the body and mind to awaken after a short nap requires practice. The old axiom ‘practice makes perfect’ could well apply to daytime naps!”

 

My feeling is that if you’re not getting your quota of sleep at night, and even if you are, then a nap is in order and will have beneficial effects all round. How often and how long you nap depends on your needs. If your sleeping at night is in order, then a 30 minute nap may work best for you on days you feel you need it. If you’re not sleeping well or long enough for one reason or another, a longer nap of at least an hour and a half might be more useful in that it may well restore the anabolic effects of sleep.

 

Two Sleeps in One?

 

Along the same lines as napping, some people feel that there’s an alternative to sleeping right through the night, especially for people who naturally wake up in the middle of the night,. This middle of the night awakening, usually occurs by breaking through light sleep to wakefulness, something that’s more common as you get older since the urge to empty the bladder half way through the night increases and can be the stimulus that awakens you in light sleep.  

 

Regardless of the reason why you wake up, it’s often hard to get back to sleep as your mind goes into hyperdrive. In these situations having two phases of sleep may be the answer to getting enough sleep. Once you wake up you can stay up for an hour or more until you feel sleepy again and then go back to bed for the second bout of sleep.

 

This biphasic sleep pattern, which may occur more than once a night and thus be polyphasic, is considered by some to be the natural way we should sleep, coupled with naps during the day.

 

This may well have been the way our more primitive ancestors slept before the modern world asserted itself as the master of your time with alarm clocks, day jobs, time constraints, artificial lighting, etc. And it may be the answer to common sleep disorders – where it’s possible that the perception that there is a disorder is the problem, when really a biphasic pattern of sleep may be more natural than sleeping straight through the night.

 

For more information on segmented of bi/polyphasic sleep, look at the work of sleep historian Roger Ekirch, especially his book, At Day's Close: Night in Times Past. 

 

Building on the Foundation

 

Getting your proper amount of sleep, all at once or in segments, will help keep you in an anabolic state and allow you to recuperate from your workouts. Now you need to work on some of those other lifestyle factors that that may be impeding your progress. For example the use of alcohol and recreational drugs can sabotage your efforts, and reducing stress and dealing positively with any emotional difficulties in your life will make it easier to reach your goals.

 

The next step is to make sure that build on your anabolic lifestyle foundation by optimizing your training, diet and nutritional supplement use. At www.MauroMD.com we cover all three. My anabolic/fat burning phase shift diets, including the Metabolic Diet, the Anabolic Diet, the Anabolic Solution, and the Radical Diet, and my line of nutritional supplements will help you reach and optimize your health, body composition and performance goals. And to further the anabolic effects of sleep I formulated NitAbol, a combination of GHboost, TestoBoost and Mysosin Protein that increases levels of testosterone, growth hormone and IGF-1 as well as decreasing catabolism by providing varying amino acid loads throughout the night.

 

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Med Hypotheses. 2013 Jun;80(6):701-5. doi: 10.1016/j.mehy.2013.02.013. Epub 2013 Mar 13.

 

Resistance exercise: a non-pharmacological strategy to minimize or reverse sleep deprivation-induced muscle atrophy.

 

Mônico-Neto M, Antunes HK, Dattilo M, Medeiros A, Souza HS, Lee KS, de Melo CM, Tufik S, de Mello MT.

 

Abstract

 

Sleep is important for maintenance of skeletal muscle health. Sleep debt can induce muscle atrophy by increasing glucocorticoids and decreasing testosterone, growth hormone and insulin-like growth factor-I. These hormonal alterations result in a highly proteolytic environment characterized by decreased protein synthesis and increased degradation. Given that sleep deprivation is increasingly prevalent in modern society, strategies to minimize or reverse its adverse effects need to be investigated. Resistance exercise has been suggested as an intervention that would benefit the muscle health. The practice of this type of exercise can increase the concentration of testosterone, growth hormone and insulin-like growth factor I and stimulate the protein synthesis through a key signaling molecule, mammalian target of rapamycin. Thus, we hypothesized that resistance exercise is an important non-pharmacological strategy to counteract deleterious effects of sleep debt on skeletal muscle.

 

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References: 


[1]Edinger JD, Glenn DM, Bastian LA, Marsh GR. Slow-wave sleep and waking cognitive performance II: Findings among middle-aged adults with and without insomnia complaints. Physiol Behav. 2000 Jul 1-15;70(1-2):127-34.

[2]Born J, Rasch B, Gais S. Sleep to remember. Neuroscientist. 2006 Oct;12(5):410-24.

[3]Voss U. Functions of sleep architecture and the concept of protective fields. Rev Neurosci. 2004;15(1):33-46.

[4]Krishnan V, Collop NA.  Gender differences in sleep disorders. Curr Opin Pulm Med. 2006 Nov;12(6):383-9.

[5]Moline ML, Broch L, Zak R.  Sleep in women across the life cycle from adulthood through menopause. Med Clin North Am. 2004 May;88(3):705-36, ix.

[6]Vanitallie TB.  Sleep and energy balance: Interactive homeostatic systems. Metabolism. 2006 Oct;55(10 Suppl 2):S30-5.

[7]Zisapel N.  Sleep and sleep disturbances : biological basis and clinical implications. Cell Mol Life Sci. Mar 15 2007; [Epub ahead of print]

[8]Everson CA. Sustained sleep deprivation impairs host defense. Am J Physiol 1993; 265:R1148-R1154.

[9]Malik, S. W. and Kaplan, J. Sleep deprivation. Prim Care 2005; 32:475-490.

[10]Orzel-Gryglewska J. Consequences of sleep deprivation. Int J Occup Med Environ Health. 2010;23(1):95-114.

[11]Bryant PA, Trinder J, Curtis N. Sick and tired: Does sleep have a vital role in the immune system? Nat Rev Immunol. 2004 Jun;4(6):457-67.

[12]Gomez-Merino D, Drogou C, Chennaoui M, Tiollier E, Mathieu J, Guezennec CY.  Effects of combined stress during intense training on cellular immunity, hormones and respiratory infections. Neuroimmunomodulation. 2005;12(3):164-72.

[13]Knutson KL. Sleep duration and cardiometabolic risk: a review of the epidemiologic evidence. Best Pract Res Clin Endocrinol Metab. 2010 Oct;24(5):731-43.

[14]Leproult R, Van Cauter E. Role of sleep and sleep loss in hormonal release and metabolism. Endocr Dev. 2010;17:11-21. Epub 2009 Nov 24.

[15]Watanabe M, Kikuchi H, Tanaka K, Takahashi M. Association of short sleep duration with weight gain and obesity at 1-year follow-up: a large-scale prospective study. Sleep. 2010 Feb 1;33(2):161-7.

[16]Morselli L, Leproult R, Balbo M, Spiegel K. Role of sleep duration in the regulation of glucose metabolism and appetite. Best Pract Res Clin Endocrinol Metab. 2010 Oct;24(5):687-702.

[17]Thompson CL, Larkin EK, Patel S, Berger NA, Redline S, Li L. Short duration of sleep increases risk of colorectal adenoma. Cancer. 2011 Feb 15;117(4):841-7. doi: 10.1002/cncr.25507.

[18]Everson CA, Crowley WR. Reductions in circulating anabolic hormones induced by sustained sleep deprivation in rats. Am J Physiol Endocrinol Metab. 2004;286(6):E1060-70.

[19]Nindl BC, Rarick KR, Castellani JW, Tuckow AP, Patton JF, Young AJ, Montain SJ. Altered secretion of growth hormone and luteinizing hormone after 84 h of sustained physical exertion superimposed on caloric and sleep restriction. J Appl Physiol. 2006;100(1):120-8. 

[20]Leproult R, Van Cauter E. Role of sleep and sleep loss in hormonal release and metabolism. Endocr Dev. 2010;17:11-21.

[21]Rosa Neto JC, Lira FS, Venancio DP, Cunha CA, Oyama LM, Pimentel GD, Tufik S, Oller do Nascimento CM, Santos RV, de Mello MT. Sleep deprivation affects inflammatory marker expression in adipose tissue. Lipids Health Dis. 2010 Oct 30;9:125.

[22]Kessler L, Nedeltcheva A, Imperial J, Penev PD. Changes in serum TSH and free T4 during human sleep restriction. Sleep. 2010 Aug 1;33(8):1115-8.

[23]Penev PD. Association between sleep and morning testosterone levels in older men. Sleep. 2007;30(4):427–432.

[24]Baumgartner A, Graf KJ, Kurten I, et al. Neuroendocrinological investigations during sleep deprivation in depression. I. Early morning levels of thyrotropin, TH, cortisol, prolactin, LH, FSH, estradiol, and testosterone. Biological Psychiatry 1990; 28(7):556-68.

[25]Vgontzas, A. N., Zoumakis, M., Bixler, E. O., Lin, H. M., Prolo, P.,Vela-Bueno,A., Kales,A. and Chrousos,G. P. Impaired nighttime sleep in healthy old versus young adults is associated with elevated plasma interleukin-6 and cortisol levels: physiologic and therapeutic implications. J Clin Endocrinol Metab 2003; 88:2087-2095.

[26]Steiger A. Eating and sleeping--their relationship to ghrelin and leptin. Am J Physiol Regul Integr Comp Physiol. 2004 Nov; 287(5):R1031-2.

[27]Littman AJ, Vitiello MV, Foster-Schubert K, Ulrich CM, Tworoger SS, Potter JD, Weigle DS, McTiernan A. Sleep, ghrelin, leptin and changes in body weight during a 1-year moderate-intensity physical activity intervention. Int J Obes (Lond). 2007 Mar;31(3):466-75.

[28]Steiger A. Ghrelin and sleep-wake regulation. Am J Physiol Regul Integr Comp Physiol. 2007 Jan;292(1):R573-4.

[29]Schussler P, Uhr M, Ising M, Weikel JC, Schmid DA, Held K, Mathias S, Steiger A. Nocturnal ghrelin, ACTH, GH and cortisol secretion after sleep deprivation in humans. Psychoneuroendocrinology. 2006 Sep;31(8):915-23.

[30]Wren AM, Seal LJ, Cohen MA, Brynes AE, Frost GS, et al. Ghrelin enhances appetite and increases food intake in humans. J Clin Endocrinol Metab. 2001;86:5992.

[31]Spiegel K, Leproult R, Tasali E, Penev P, Van Cauter E. Sleep curtailment results in decreased leptin levels and increased hunger and appetite. Sleep. 2003;26:A174.

[32]Leibel RL. The role of leptin in the control of body weight. Nutr Rev. 2002;60:S15–S19.

[33]Nedeltcheva AV, Kilkus JM, Imperial J, Schoeller DA, Penev PD. Insufficient sleep undermines dietary efforts to reduce adiposity. Ann Intern Med. 2010 Oct 5;153(7):435-41.

[34]Gangwisch JE, Malaspina D, Boden-Albala B, Heymsfield SB. Inadequate sleep as a risk factor for obesity: analyses of the NHANES I. Sleep. 2005 Oct 1;28(10):1289-96.

[35]Spiegel K, Knutson K, Leproult R, Tasali E, Van Cauter E. Sleep loss: a novel risk factor for insulin resistance and Type 2 diabetes. J Appl Physiol. 2005 Nov;99(5):2008-19.

[36]Buxton OM, Pavlova M, Reid EW, Wang W, Simonson DC, Adler GK. Sleep restriction for 1 week reduces insulin sensitivity in healthy men. Diabetes. 2010 Sep;59(9):2126-33.

[37]Nedeltcheva AV, Kilkus JM, Imperial J, Schoeller DA, Penev PD. Insufficient sleep undermines dietary efforts to reduce adiposity. Ann Intern Med. 2010 Oct 5;153(7):435-41.

[38]Broussard JL, Ehrmann DA, Van Cauter E, Tasali E, Brady MJ. Impaired insulin signaling in human adipocytes after experimental sleep restriction: a randomized, crossover study. Ann Intern Med. 2012 Oct 16;157(8):549-57.

[39]Taheri S, Lin L, Austin D, Young T, Mignot E. Short sleep duration is associated with reduced leptin, elevated ghrelin, and increased body mass index. PLoS Med. 2004 Dec;1(3):e62. Epub 2004 Dec 7.

[40]Mullington JM, Chan JL, Van Dongen HP, Szuba MP, Samaras J, et al. Sleep loss reduces diurnal rhythm amplitude of leptin in healthy men. J Neuroendocrinol. 2003;15:851–854.

[41]Copinschi G. Metabolic and endocrine effects of sleep deprivation. Essent Psychopharmacol. 2005;6(6):341-7.

[42]Souissi N, Souissi M, Souissi H, Chamari K, Tabka Z, Dogui M, Davenne D. Effect of time of day and partial sleep deprivation on short-term, high-power output. Chronobiol Int. 2008 Nov;25(6):1062-76.

[43]Samuels C. Sleep, recovery, and performance: the new frontier in high-performance athletics. Phys Med Rehabil Clin N Am. 2009 Feb;20(1):149-59, ix.

[44]Oliver SJ, Costa RJ, Laing SJ, Bilzon JL, Walsh NP. One night of sleep deprivation decreases treadmill endurance performance. Eur J Appl Physiol. 2009 Sep;107(2):155-61.

[45]Azboy O, Kaygisiz Z. Effects of sleep deprivation on cardiorespiratory functions of the runners and volleyball players during rest and exercise. Acta Physiol Hung. 2009 Mar;96(1):29-36.

[46]Skein M, Duffield R, Edge J, Short MJ, Mündel T. Intermittent-Sprint Performance and Muscle Glycogen Following 30 H Sleep Deprivation. Med Sci Sports Exerc. 2010 Dec 21. [Epub ahead of print]

[47]Gettler LT, McKenna JJ, McDade TW, Agustin SS, Kuzawa CW.PLoS One. 2012;7(9):e41559. doi: 10.1371/journal.pone.0041559. Epub 2012 Sep 5. Does cosleeping contribute to lower testosterone levels in fathers? Evidence from the Philippines.

[48]Too much, too little sleep associated with adult weight gain. Mayo Clin Womens Healthsource. 2008 Oct;12(10):3.

[49]Bluhm G, Nordling E, Berglind N.  Road traffic noise and annoyance--an increasing environmental health problem. Noise Health. 2004 Jul-Sep;6(24):43-9.

[50]Brainard G, Rollag MD, Hanifin JP. Photic regulation of melatonin in humans: ocular and neural signal transduction. J Biol Rhythms 1997; 12:575–578.

[51]Fucci RL, Gardner J, Hanifin JP, Jasser S, Byrne B, Gerner E, Rollag M, Brainard GC. Toward optimizing lighting as a countermeasure to sleep and circadian disruption in space flight. Acta Astronaut. 2005 May-Jun;56(9-12):1017-24.

[52]Lockley SW, Brainard GC, Czeisler CA. High sensitivity of the human circadian melatonin rhythm to resetting by short wavelength light. J Clin Endocrinol Metab 2003; 88:4502–4505.

[53]Feige B, Gann H, Brueck R, Hornyak M, Litsch S, Hohagen F, Riemann D. Effects of alcohol on polysomnographically recorded sleep in healthy subjects. Alcohol Clin Exp Res. 2006 Sep;30(9):1527-37.

[54]Dorfman LJ, Jarvik ME. Comparative stimulant and diuretic actions of caffeine and theobromine in man.Clin Pharmacol Ther. 1970;11(6):869-72.

[55]Baran AS, Chervin RD. Approach to the patient with sleep complaints. Semin Neurol. 2009 Sep;29(4):297-304.

[56]Bailes S, Baltzan M, Rizzo D, Fichten CS, Amsel R, Libman E. A diagnostic symptom profile for sleep disorder in primary care patients. J Psychosom Res. 2008 Apr;64(4):427-33.

[57]Morin CM, Koetter U, Bastien C, Ware JC, Wooten V. Valerian-hops combination and diphenhydramine for treating insomnia: a randomized placebo-controlled clinical trial. Sleep. 2005 Nov 1;28(11):1465-71.

[58]Bent S, Padula A, Moore D, Patterson M, Mehling W. R Valerian for sleep: a systematic review and meta-analysis. Am J Med. 2006 Dec;119(12):1005-12.

[59]Donath F, Quispe S, Diefenbach K, Maurer A, Fietze I, Roots I. Critical evaluation of the effect of valerian extract on sleep structure and sleep quality. Pharmacopsychiatry. 2000 Mar;33(2):47-53.

[60]Poyares DR, Guilleminault C, Ohayon MM, Tufik S. Can valerian improve the sleep of insomniacs after benzodiazepine withdrawal? Prog Neuropsychopharmacol Biol Psychiatry. 2002 Apr;26(3):539-45.

[61]Shinomiya K, Inoue T, Utsu Y, Tokunaga S, Masuoka T, Ohmori A, Kamei C. Effects of kava-kava extract on the sleep-wake cycle in sleep-disturbed rats. Psychopharmacology (Berl). 2005 Jul;180(3):564-9.

[62]Capasso A, Sorrentino L. Pharmacological studies on the sedative and hypnotic effect of Kava kava and Passiflora extracts combination. Phytomedicine. 2005 Jan;12(1-2):39-45.

[63]Lehrl S. Clinical efficacy of kava extract WS 1490 in sleep disturbances associated with anxiety disorders. Results of a multicenter, randomized, placebo-controlled, double-blind clinical trial. J Affect Disord. 2004 Feb;78(2):101-10.

[64]Teschke R, Sarris J, Lebot V. Kava hepatotoxicity solution: A six-point plan for new kava standardization. Phytomedicine. 2011 Jan 15;18(2-3):96-103.

[65]Schneider-Helmert D, Spinweber CL. Evaluation of L-tryptophan for treatment of insomnia: a review. Psychopharmacology (Berl) 1986; 89:1-7.

[66]Gorfine T, Assaf Y, Goshen-Gottstein Y, Yeshurun Y, Zisapel N. Sleep-anticipating effects of melatonin in the human brain. Neuroimage. 2006 May 15;31(1):410-8.

[67]Radogna F, Diederich M, Ghibelli L. Melatonin: a pleiotropic molecule regulating inflammation. Biochem Pharmacol. 2010 Dec 15;80(12):1844-52.

[68]Reiter RJ, Tan DX, Fuentes-Broto L. Melatonin: a multitasking molecule. Prog Brain Res. 2010;181:127-51.

[69]National Sleep Foundation. Summary findings of the 2005 Sleep in America poll. See http://www.sleepfoundation.org.

[70]Masa JF, Rubio M, Perez P, Mota M, de Cos JS, Montserrat JM. Association between habitual naps and sleep apnea. Sleep. 2006 Nov 1;29(11):1463-8.

[71]Pilcher JJ, Michalowski KR, Carrigan RD. The prevalence of daytime napping and its relationship to nighttime sleep. Behav Med 2001; 27:71-76.

[72]Campbell SS, Murphy PJ, Stauble TN. Effects of a nap on nighttime sleep and waking function in older subjects. J Am Geriatr Soc 2005; 53:48-53.

[73]Dhand R, Sohal H. Good sleep, bad sleep! The role of daytime naps in healthy adults. Curr Opin Pulm Med. 2006 Nov;12(6):379-82.

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