Aging
Although sleep may become more fragile in older people, the need for sleep does not decrease with age. (Sleep-Wake Cycle. National Sleep Foundation, USA.)
Amount Needed
There is no magic number. The optimum amount of sleep you need may be different for you than for someone else of the same age and gender. A 2005 study confirmed the fact that sleep needs vary across populations. (How Much Sleep do we Really Need? National Sleep Foundation, USA.)
It is a common misconception that sleep needs decline with age. In fact, research demonstrates that our sleep needs remain constant throughout adulthood. (Aging and Sleep. National Sleep Foundation.)
SPECT Study: The brains of people who got less than six hours of sleep a night showed marked decreased perfusion. Inadequate sleep is associated with irritability, periods of spaciness, mood instability, decreased cognitive ability (e.g., temporal lobe problems). (Amen, Daniel G., MD. Change Your Brain Change Your Life. P. 208-209. NY:Times Books, 1998.)
Most newborns spend 50% of their sleeping time in D sleep (needed to consolidate new learning) and this is higher for premies. By age of 10 amount of time devoted to D sleep decreases to 25% and remains at that level well into old age. (Greenfield, Susan, con. Ed. Brain Power, Working out the Human Mind. Great Britain: Element books Limited, 1999, p. 101)
Stanford professor Dr. William C. Dement, a leading authority on sleep/sleep deprivation challenges his students to figure out the optimum amount their brains need. Guesstimate how much you need (e.g., 8 hours). Get 10 hours for a number of nights. You will reach a point where you feel wide awake and alert all day and wake up spontaneously every morning. That number of hours typically represents your brain’s needs. (Students are Falling Deeply in Debt - Sleep Debt that is! 2005, Volume 7, Issue 3 of Sleepmatters. 2005.)
Benefits
Sleep has been found to:
- Promote memory consolidation
- Help you learn faster
- Makes you feel refreshed
- Boosts immune health
- Help maintain energy balance
- Improve athletic performance by enhancing motor skills
(Sleep. Columbia University Health Services.)
You spend about one-third of your life sleeping. Far from being unproductive, this plays a direct role in how full, energetic and successful the other two-thirds of your life can be. (What Happens When You Sleep. National Sleep Foundation, USA.)
Brain
The brain appears to need sleep more than the body. Studies: by 20 hours without sleep, your reaction time is similar to a person with a blood alcohol level of 0.08. After 24 hours without sleep, the brain’s ability to use glucose drops off dramatically. (Gorman, Christine. Why We Sleep. NY: Time Inc., Time. Vol 164, No 25, Dec 20, 2004, p. 46-59.)
The brain demands sleep – it is not a choice. Without sufficient sleep the brain may not complete housecleaning tasks effectively. This involves re-uptake of serotonin and norepinephrine (important for wakefulness, alertness, and good mood) as well as the processing of memory traces from the day. (Giuffre, Kenneth, MD, and Theresa Foy DiGeronimo. The Care and Feeding of Your Brain. NJ:The Career Press Inc, 1999, p. 101.)
Adequate sleep is critical to optimum brain function. To get a good night’s sleep naturally, avoid alcohol and marijuana, eliminate nicotine, and get stimulants out of your system well before bedtime (e.g., caffeine should not be consumed for six to eight hours before bedtime. (Amen, Daniel G., MD. Magnificent Mind at Any Age. NY:Harmony Books, 2008, p. 116-119)
Creativity
German scientists reported having demonstrated for the first time that your sleeping brain continues working on problems that may have baffled you during the day. An answer may come more easily after eight hours of rest. (Study Confirms Sleep Essential for Creativity. Health. CNN.com, 2004.)
Cycle of Sleep
The architecture of sleep follows a pattern of alternating REM (rapid eye movement) and NREM (non-rapid eye movement) sleep throughout a typical night in a cycle that repeats itself about every 90 minutes. (Article. Sleep-Wake Cycle. National Sleep Foundation, USA.)
Debt
It’s a myth that you can cheat successfully on the amount of sleep you get. Without adequate sleep you accumulate a sleep debt that can be difficult to pay back, especially if it becomes too large. (Article. Myths and Facts About Sleep. National Sleep Foundation, USA.)
Deprivation
Sleep deprivation actually damages brain cells. (Carper, Jean. Your Miracle Brain. NY: HarperCollins Publishers, Inc., 2000, p. 189-190.)
Sleep deprivation can cause an increase in cortisol, a stress hormone, excesses of which can cause memory impairment, high blood pressure, weakened immune system, and depression. (Greenwood-Robinson, Maggie, PhD. 20 / 20 Thinking. NY: Avery, Putnam Special Markets, 2003, p. 197-198.)
Sleep deprivation has been linked to health problems such as obesity and high blood pressure, negative mood and behavior, decreased productivity, and safety issues in the home, on the job, and on the road. (Myths and Facts About Sleep. National Sleep Foundation, USA.)
When you are sleep deprived, the boundaries between sleep and wakefulness may often become blurred. Recently research has shown that state "dissociation" is more common that anyone previously suspected. State dissociation is defined as the presence of more than one vigilance state concurrently. Vigilance states include awake, rapid eye (REM) movement sleep, and non-REM sleep). Forgetfulness and daydreaming may be examples of this, but also more bizarre and even criminal behaviors could be, as well. And perhaps 20% of all vehicle accidents are related to fatigue.
http://www.newscientist.com/article/mg20427291.000-are-you-asleep-exploring-the-minds-twilight-zone.html?full=true
Enhancing Sleep
All colas contain caffeine (so should be avoided before sleep). Diet colas may be even more problematic for two reasons: Sugar, the carbohydrate that would help exert a sedating influence, is absent; the artificial sweeteners act as a direct stimulant to the brain. ( Guiffre, Kenneth, MD, with Theresa Foy DiGeronimo. The Care and Feeding of Your Brain. NJ: Career Press, 1999, p. 114)
Eating some dry cereal or instant hot cereal made with boiling water (no milk) before bedtime can trigger serotonin, a sleep-inducing strategy. (Bricklin, Mark, et al. Positive Living and Health. PA: Rodale Press, 1990, p. 89-90.0
When people get less than eight hours of sleep, concentration is only 70% of what it is on days when they are well rested; likely caused by the depletion of norepinephrine, and serotonin. Chronic stress-like syndrome from sleep deprivation raises brain cortisol levels, which over time can cause cell death. (Giuffre, Kenneth, MD, with Theresa Foy DiGeronimo. The Care and Feeding of Your Brain. NJ: Career Press, 1999, p. 43.)
Researchers at UCLA have found that loss of sleep, even for a few hours during the night, can prompt a person’s immune system to turn against healthy tissue and organs. The study was based on measurements of levels of nuclear factor (NF)-KB, a transcription factor that serves a vital role in the body's inflammatory signaling. Experts recommend that adults get between seven and eight hours of sleep every night. (Loss Of Sleep, Even For A Single Night, Increases Inflammation In The Body. Science Daily, 2008.)
Acute or chronic sleep deprivations impairs mental abilities and can lead to high blood sugar levels due to insulin resistance, a precursor of type 2 diabetes, as well as elevated brain cortisol levels--both associated with memory loss. This can repair itself if you spend approximately 12 hours in bed to make up for the sleep deficit. (Small, Gary, M.D. The Memory Bible. NY: Hyperion, 2002, p. 183-184.)
Electromagnetic Spectrum
Electromagnetic wavelengths that activate the mammalian retina (E.g., light), play a huge role in regulating melatonin production. Circulating levels of melatonin are low during daylight hours (e.g., visible light suppresses production of melatonin) and increase with onset of darkness. High melatonin production is incompatible with exposure with bright light exposure. Visible light in the blue-green spectrum are most likely to inhibit production of melatonin. (Lin, James C., Editor. Advances in Electromagnetic Fields in Living Systems, Volume 2. NY: Springer, 1997. Chapter 1 by Russel J. Reiter: Melatonin Aspects of Exposure to Low Frequency Magnetic and Electric Fields, p. 4-5.)
Exercise
Refer to Exercise and the Brain for additional information
Exercise promotes sound sleep (e.g., raises baseline serotonin, helps with stress management, increases core body temperature by a couple of degrees), but timing is important. Avoid exercising too close to bedtime. Rather do it in the late afternoon or early evening. (Giuffre, Kenneth, MD, with Theresa Foy DiGeronimo. The Care and Feeding of Your Brain. NJ: Career Press, 1999, p. 119-120.)
Immune System
There is a clear biochemical link between the function of immune system cells and deep sleep. (Ornstein, Robert, PhD, and David Sobel, MD. Healthy Pleasures. NY: Addison-Wesley, 1989, p. 120-122.)
Insomnia
You can retrain yourself and develop good sleep habits. Lack of restful sleep can result in lower quality of life in older adults, memory problems, and depression, to name just a few. (O’Brien, Mary, MD. Successful Aging. CA:Biomed General. 2007, p. 56.)
Melatonin
The production of melatonin can be thrown off during winter months when amount of daylight decreases, especially in northern regions. This can trigger a form of depression known as SAD, Seasonal Affective Disorder. Along with other typical symptoms of depression, people with SAD tend to eat and sleep more. Exposure to “full-spectrum lighting” has been used successfully to treat this type of depression. (Giuffre, Kenneth, MD., with Teresa Foy DiGeronimo. The Care and Feeding of Your Brain. NJ: Career Press, 1999, p. 100, 175.)
Problem-Solving
While we sleep the mind continues to work (e.g., processes information, stores memories, solving problems). The subconscious is free to take an unorthodox approach. (Fontana, David, PhD. Teach Yourself to Dream. San Francisco, CA: Chronicle Books, 1997, p. 60-64.)
REM and Creativity
Study at the University of California San Diego: volunteers who entered rapid eye movement (REM) states during sleep improved their creative problem solving ability by almost 40% (as compared with quiet rest and non-REM sleep. The passage of time is enough for the brain to find solutions for creative problems that the person has already been working on. Lead researcher Professor Sara Mednick said: "For new problems, only REM sleep enhances creativity." Apparently REM sleep allows the brain to form new nerve connections without the interference of other thought pathways that occur when the brain is awake or in non-dream-state sleep. (Article.)
Television
Watching scenes of violence or novelty (e.g., sitcom) can increase brain arousal and interfere with sleep. Sleeping with the TV on (e.g., a light that makes noise) interferes with natural melatonin production and can result in more waking during lighter stages of sleep. (Giuffre, Kenneth, MD., with Teresa Foy DiGeronimo. The Care and Feeding of Your Brain. NJ:Career Press, 1999, p. 122.)
Brain References 
