Sleep and your precious brain (Part I)
You know that wonderful feeling you have after waking up from a fabulous sleep? You're relaxed and happy, alert but calm! Unfortunately, fewer and fewer people are experiencing that wonderful feeling because sleep, or, more accurately, the lack of it, is becoming a huge problem around the world. Unfortunately, the problem started with one of mankind's most celebrated inventions. Edison’s famous light bulb invention in the 1880s changed our approach to the "daylight–wake-up" vs. "nighttime–sleep-time" pattern that we had become accustomed to from the beginning of time, and which even single-celled organisms adhere to.
We now live in a 24/7 world, where people are scared they will miss out on something interesting, or financially rewarding, or fun, if they go to bed on time. Add shift workers, international travelers, students and workaholics to this mix and you have a planet that is continuously pushing the boundaries of physical and mental well-being by ignoring one of the body's most basic needs – deep, peaceful, rejuvenating sleep. We have changed a basic, evolutionary urge to suit a modern-day technological phenomena, and this has resulted in negative changes to our health. One of the top researchers in this area believes that we are in the middle of the biggest experiment in sleep deprivation and there are not going to be any positive side effects!
A multimillion-dollar industry
Millions of people suffer from an inability to fall asleep, stay asleep, or both. According to the Centre of Disease Control, up to 90 million Americans reported that they were thinking about things or remembering things, which kept them form sleeping. The CDC also states that "insufficient sleep is a public health epidemic" in America.
It is estimated that between 10 and 20% of the global population are currently using sleeping tablets or anxiolytics, to relieve insomnia. Although sleeping aids were generally confined to the elderly, people across all age groups are now using medication, with the doubling up of the number of people using them who belong to the 20–45 age group. The predicated cost of sleeping aids to the population is being set to reach $9 billion US by 2015. America is the biggest user of sleeping aids, at 48% of the global market. Australians are filling more than 5 million sleeping tablet prescriptions per year, and doctors fill 10 million sleeping aid prescriptions per year in the UK, half of which are true sleeping tablets and the other half which are anxiolytics. Although figures for South Africa were not available at the time of writing this article, it is not hard to imagine that the problem is also escalating in that country.
Why are sleep problems so prolific?
Unfortunately, the desire and need to sleep don't always coincide with the ability to do so. Living as we do in a world that is awake at the touch of a button or two, has led to many people stretching the boundaries of their days. Coupled with a very competitive work arena, and complicated relationship challenges, people find it very difficult to switch off after a full day's work. Being disciplined enough to switch off to technology, and remove any "beeping" devices from our bedrooms for the whole night doesn't come easily to many people. And adolescents and young adults may find it even harder.
An inadequate diet means fewer critically important nutrients are absorbed – nutrients that are required to facilitate the manufacture of compounds that make sleep possible and restful. In addition, a malnourished person will have blood sugar ups and downs, another reason for poor sleep patterns. Unstable blood glucose levels increase levels of specific stress hormones, which further lead to poor sleep.
An ancient desire and need
Your body adapted to spend a third of its life asleep, which is a solid eight hours a night. There are a few – very few – unusual people who seem to need less sleep, but researchers believe this is an aberration, definitely not the norm. The specific cycles of sleep have specific functions, and these influence your thinking and memory, immune and endocrine systems, your rate of growth during childhood and adolescence and your rate of aging.
It seems that the human brain has a built-in mechanism that promotes alert-wakefulness during the day and promotes sleepiness when night approaches. Researchers believe that this is why shift workers, who often work through the night, have difficulty establishing and maintaining consistent sleep patterns. In addition, they also suffer significantly more health problems, including weight gain and depression.
Researchers believe that the different stages of sleep that occur during the night accomplish various tasks in the brain, and have to occur to keep your brain healthy. When these stages of sleep, which follow a particular pattern, are disrupted, or you don’t have enough sleep, your brain will not be as alert or as capable of learning or remembering things. Your mental processing speed and accuracy, as well as spatial learning, reaction time and working memory are all influenced negatively and you could also become emotionally unstable when your sleep is disrupted.
Shallow sleep occurs as you fall asleep, and is also called stage 1 and 2 sleep. During this sleep stage, you can be awakened very easily. Deep sleep, or stage 2 and 3 sleep, occurs next. Rapid eye movement, or REM sleep occurs next, and then the cycle is repeated, taking between 90 and 120 minutes to complete one whole cycle. Researchers believe that we should have between 4 to 6 of these cycles every night, which adds up to between 7 and 8 hours each night.
Your brain is doing different things during these different stages of sleep. When your brain moves into deep sleep, the parts of your brain that focus on arousal slow down, as do areas that are involved in controlling the movement of muscles. The areas involved in sending information to consolidate or retrieve memories slow down considerably, and the area alert for sensory input virtually shuts down. Your brain becomes quiet and uses very little energy compared to when you are awake and alert, although laying down memories of things you learned during the day continues. Researchers believe this type of sleep enhances creativity. During this stage of sleep, your energy reserves are also replenished, and if you are severely deprived of sleep, you may not sleep longer when you do finally go to sleep, but you will experience a lot more of this kind of deep sleep.
Do you need less sleep as you get older?
The belief that many people have, about needing less sleep as they get older, is not based on scientific fact. We continue to need the same amount of sleep regardless of getting older. However, unfortunately, as we get older, our ability to go into the deep stages of sleep seems to become impaired and although we experience about 20% of our sleep as deep stage sleep when we are young adults, it declines to just over 3% of our sleep in middle age. Researchers believe that this is one of the reasons that aging reduces our creativity and general cognitive ability. So, although they don’t know exactly why this occurs, it does, and we should do whatever we can to improve our sleep as we get older. Insomnia and decreases in sleep duration hamper the ability to optimally perform cognitive tasks, which can then lead to further cognitive decline if the problem continues.
Exactly why do we sleep?
Researchers intrigued by sleep have spent countless hours investigating why our desire for sleep is so strong and why we get ill and eventually die when we are severely sleep deprived. Looking at what a sleeping brain does, has given them clues to follow in this search. Allowing our brains to rest and therefore replenish energy stores, to lower the brain's temperature, or to detoxify the brain are all explanations given, as to why sleep is imperative.
Researchers who deprived people of sleep discovered that they would be more severely distressed and unable to function properly from lack of REM sleep as compared to being deprived of light or deep sleep stages. So, one of the important reasons that we sleep is to dream. But why? The areas of your brain that are used during dreaming, are areas that are not used very often during your awake state. It may be that to keep these areas in working condition, we have to use them to dream.
And, we may dream to solve problems that are not easily solved using our logical, methodical frontal lobes, but which need a creative, illogical pattern of thinking to be solved. For example, a dream inspired Robert Louis Stevenson to write his famous book, Dr Jekyll and Mr Hyde; Albert Einstein dreamt about pursuing a light beam, and his theory of relativity; Samuel Taylor Coleridge, dreamed about his famous stories, the Khubla Khan and The Rime of the Ancient Mariner before writing them; Paul McCartney heard the tune for the famous song Yesterday, in a dream; the basis for the periodic table was dreamed by nineteenth-century Chemist Dimitri Mendeleyev, which led to him, upon waking, to write out the entire periodic table, which forms the basis of modern chemistry.
Other theories about why we sleep include that it reinforces changes in the brain that are produced by our experiences, or learning. So, sleep helps you to make a memory of what you have learned or experienced during the day. When you are exposed to a lot of new information or experiences during the day, you will experience more REM sleep, researchers have found. And when you experience more REM sleep, you will also consolidate emotional information from the day more efficiently. Lots of deep sleep will help you to remember and be able to recall a new motor task that you have learned during the day, while a combination of lots of REM and deep sleep will help you to better retain perceptual information.
Interestingly, when researchers looked at specific neurons involved in learning a new task during the day, they found the same ones were busy during the night, during the stage of deep sleep. Sleep may be the time when the brain practices new memory patterns, to transfer them into long-term memory. Researchers believe this to be true because there are specific molecular signaling pathways that are sensitive to sleep deprivation. Therefore, sleep could be promoting brain plasticity or facilitating its occurrence to lay down memories. There are researchers who believe this is not true, and they continue to debate this issue. However, whether sleep helps you to store memories or not, it has some imperative and essential function to perform, that is important for your cognitive health.
Another simple explanation given for the benefit of sleeping, is that when you sleep, your blood pressure drops – lowering your blood pressure is good for your heart, and remember, what is good for your heart is also good for your brain. When you work overtime or suffer from insomnia, your heart has to work harder as your blood pressure doesn’t drop, so you can increase your likelihood of heart disease, which will put your brain at risk, because of lack of blood flow and therefore, ultimately, oxygen to the brain.
Researchers have also found that sleep deprivation can lead to a disruption in the balance of hormones that are involved in the production of energy in our bodies, which can lead to overeating and ultimately weight gain and obesity, which in turn negatively influence cognitive functioning. It would seem that when you are tired you eat more to try to get the energy that you need for your daily tasks, and which you didn’t generate naturally through restorative sleep. You are also too tired to exercise, so don’t get the physical workout that is beneficial for a deep sleep, and you may also eat more because you are feeling emotionally drained and tired.
In part two you will discover what rats have taught us about our sleep patterns, what the most important sleep hormones are AND what the real sleep ‘helpers’ are and what the biggest sleep-aid ‘myth’ is.
Akhondzadeh S, et al. Passionflower in the treatment of generalized anxiety: a pilot double-blind randomized controlled trial with oxazepam. J Clin Pharm Ther 2001 Oct; 26(5): 363–7.
Bice, K, Van den Berg, L. Sleep-deprived Australians are popping more pills than ever to get a good night's kip. Available: http://www.dailytelegraph.com.au/sleep-deprived-australians-are-popping-more-pills-than-ever-to-get-a-good-nights-kip/story-e6freuy9-1226353499421 (accessed 30 Jan 2014).
Burne, J for Mail Online. Is there any such thing as a safe sleeping pill? Experts warn they raise the risk of Alzheimer's. Available: http://www.dailymail.co.uk/health/article-2214871/Is-thing-safe-sleeping-pill-Experts-warn-raise-risk-Alzheimers.html (accessed 30 Jan 2014).
Catalá A. The function of very long chain polyunsaturated fatty acids in the pineal gland. Biochim Biophys Acta 2010 Feb; 1801(2): 95-9.
Chaput JP, et al. The association between sleep duration and weight gain in adults: a 6-year prospective study from the Quebec Family Study. Sleep 2008 Apr 1; 31(4):517–23.
Czeisler CA, Gooley JJ. Sleep and circadian rhythms in humans. Cold Spring Harb Symp Quant Biol 2007; 72:579–97.
Dr Dharma Singh Khalsa and Cameron Stauth. The mind miracle. UK: Arrow Books; 1998.
Ellenbogen JM, et al. Interfering with theories of sleep and memory: sleep, declarative memory, and associative interference. Curr Biol 2006 Jul 11; 16(13):1290–4.
Gyllenhaal C, et al. Efficacy and safety of herbal stimulants and sedatives in sleep disorders. Sleep Med Rev 2000 Jun; 4(3): 229–251.
Havekes R, et al. The impact of sleep deprivation on neuronal and glial signaling pathways important for memory and synaptic plasticity. Cell Signal 2012 Jun; 24(6):1251–60.
Insufficient Sleep Is a Public Health Problem. Available: http://www.cdc.gov/features/dssleep/ (accessed 30 January 2014).
Global Industry Analysts, Inc. (GIA). Global Sleeping Pills Market to Reach US$9.0 billion by 2015. Available: http://www.prweb.com/releases/sleeping_pills/sleeping_tablets/prweb4318034.htm (accessed 30 Jan 2014).
Jakobson Ramin C. Carved in sand - when attention fails and memory fades in midlife. New York: Harper Luxe - Harper Collins Publishers, New York; 2007.
Jones BE. Glia, adenosine and sleep. Neuron 2009 Jan 29; 61(2): 156–7.
Khalsa SB. Treatment of chronic insomnia with yoga: a preliminary study with sleep-wake diaries. Appl Psychophysiol Biofeedback 2004 Dec; 29(4): 269–78.
Kumar VM. Sleep and sleep disorders. Indian J Chest Dis Allied Sci 2008 Jan-Mar; 50(1):129–35.
Lemoine P, et al. Prolonged-release melatonin improves sleep quality and morning alertness in insomnia patients aged 55 years and older and has no withdrawal effects. J Sleep Res 2007 Dec; 16(4): 371–80.
Meerlo P, et al. New neurons in the adult brain: the role of sleep and consequence of sleep loss. Sleep Med Rev 2009 Jun; 13(3):187–94.
Meletis CH, Barker JE. Herbs and Nutrients for the mind - a guide to natural brain enhancers. USA: Praeger Publ, Westport, Connecticut; 2004.
Michaud E with Bain J. Sleep to be sexy, smart and slim. Readers Digest 2008; USA.
Robert Louis Stephenson. A Chapter on Dreams. Across the Plains with Other Memories and Essays. London: Chatto and Windus; 1892.
John Stuart. Robert Louis Stevenson, A Critical Biography Vol. 2: Kessinger Publishing; 2005.
Schmid SM, et al. A single night of sleep deprivation increases ghrelin levels and feelings of hunger in normal-weight healthy men. J Sleep Res 2008 Sep; 17(3): 331–4.
Singh R, et al. Effect of paradoxical sleep deprivation on oxidative stress parameters in brain regions of adult and old rats. Biogerontology 2008 Jun; 9(3):153–62.
Talamini LM, et al. Sleep directly following learning benefits consolidation of spatial associative memory. Learn Mem 2008 Apr 3; 15(4):233–7.
Trenell MI, et al. Sleep and metabolic control: waking up to a problem? Clin Exp Pharmacol Physiol 2007 Jan-Feb; 34(1–2):1–9.
Vecsey CG, et al. Genomic analysis of sleep deprivation reveals translational regulation in the hippocampus. Physiol Genomics2012 Oct 17; 44(20):981–91.
Wade A, Downie S. Prolonged-release melatonin for the treatment of insomnia in patients over 55 years. Expert Opin Investig Drugs 2008 Oct; 17(10): 1567–72.
Walker MP, Stickgold R. Sleep, memory, and plasticity. Annu Rev Psychol 2006; 57:139–66.
Winkelman JW, et al. Reduced brain GABA in primary Insomnia: preliminary data from 4T Proton Magnetic Resonance Spectroscopy (1H-MRS). Journal of Sleep 2008 Nov; 31(11): 1499–1506.
Wright KP Jr, et al. Sleep and wakefulness out of phase with internal biological time impairs learning in humans. J Cogn Neurosci 2006 Apr; 18(4):508–21.
Yehuda S, et al. Essential fatty acids and sleep: mini-review and hypothesis. Med Hypotheses 1998 Feb; 50(2): 139–45.
Young SN. Clinical nutrition: 3. The fuzzy boundary between nutrition and psychopharmacology. CMAJ 2002 Jan 22; 166(2): 205–9.