How many hours of sleep does and infant, child, and adult person need at night?
A. Children under 5 years old need approximately 12-18 hours of sleep per night. School age children between the ages of 5-10 years old need about 10-11 hours of sleep each night. Teens require any where from 8-10 hours of sleep each night. Adults require about 7-9 hours of sleep each night.
Getting too little of sleep creates a ‘sleep debt’. Loosing sleep one day means sleeping longer the next day. The body demands that about 1/3 to 1/2 of total lost sleep be recovered hour for hour. The physical effects of sleep loss include increased appetite, a drop in body temperature, increased sensitivity to pain, and feelings of drowsiness. The immune system is weakened by deprived sleep. Shakiness, visual problems, and headaches go along with sleep loss.
Sleep Disorders are classified in three major categories, lack of sleep, disturbed sleep, and excessive sleep. The following are a few of the types of well known and studied sleep problems. -Insomnia is the inability to fall asleep. It is a common sleep problem that most people experience at least occasionally. People feel tired much of the time, and it often disrupts daily life. -Sleep apnea is interrupted breathing during sleep. It usually occurs because of a mechanical problem in the windpipe, but it also can indicate a neurological disorder involving nerve cells. -REM sleep behavior disorder causes disruptions in the brain during REM sleep. During REM ( the dream phase of sleep), an area of the brainstem called the pons sends signals to the cerebral cortex, which is the area of the brain responsible for thinking and organizing information. The pons also sends signals to muscles in the body during REM. For example, if a patient with REM sleep behavior disorder dreams about running, he or she might actually get up and run. -Restless legs syndrome , and periodic limb movement disorder, are common sleep disorders in the elderly. RLS is a genetic disorder resulting in prickly or tingling sensations in the leg that cause patients to want to move their legs. It often results in insomnia. PLMD causes jerking in the legs or arms that occurs frequently during resting or sleeping. Jerking may occur as many as 3 times in a minute and each jerk can wake the patient. -Narcolepsy is a condition that causes patients to fall asleep uncontrollably throughout the day for periods lasting less than a minute to more than half an hour. They enter REM sleep prematurely without going through the normal sequence of sleep stages.
The purpose of sleep allows a person’s brain to consolidate memories. The things that are learned are collected, stored, and dispersed by the hippocampus. Scientists are confident that sleep plays a significant role in organizing the data of new information learned and redirecting it to long term storage regions within the brain. Various scientific tests have revealed that REM sleep plays a significant role in organizing information and forming the links that make lasting memories. Electrical delta waves during sleep block conscious thinking. It is during this sleep phase that restorative processes take place, (called homeostatic rebalancing). When the quality of the normal electrical rhythms of sleep is poor, there is a dramatic decline in working memory. Good sleep increases a person’s coping skills which helps to manage life’s stressors in a healthy manner.
Are You The Lark Or An Owl? The ‘larks’ are considered morning people, who eagerly wake happily with the sunrise; and the ‘owls’, are night people, who hit their stride when the sun goes down, and cannot seem to awake before noon. Decide whether you mostly agree or disagree with each of these statements: 1.) Bedtime for me is usually 10 p.m. or earlier. 2.) I’d love to get up at 9 a.m. or even later if I could. 3.) I usually feel sleepy before 10 p.m. 4.) If I didn’t use an alarm clock, I probably wouldn’t get up until lunchtime. 5.) Getting up in the morning is easy for me. 6.) I feel lousy when I first get up. 7.) I feel Hungary soon after I get up. 8.) I don’t want to exercise in the morning, and if I’m forced to, I do poorly. 9.) I would rather take a difficult test in the morning than any other day. 10.) If I get to bed by midnight, I feel fine the next day. 11.) Even if I get to bed late, I wake up around my usual time. 12.) If I could choose my own school or work hours, I would prefer to start in the afternoon and work until midnight. 13.) I feel my best before noon. 14.) I would rather stay up late to study or do homework than get up early. 15.) If I could do as I please, I would usually get up before 9 a.m. Score yourself. For every odd number that you agree with, give yourself one point. For every even numbered item that you disagree with, give yourself one point. If you score 11-15, you are a ‘lark ‘. Five or less makes you an ‘owl’. A score of 6-10 means that you are mixed, and capable of being both a morning and evening person.
The circadian rhythm is a 24 hour biological cycle. All animals and most plants posses this and many other biological clocks.
At the base of a human brain is the hypothalamus. The suprachiasmatic nucleus of the hypothalamus serves as a biological clock that regulates the sleep-wake cycle that keeps our body in a state of regular homeostasis. The hypothalamus continually measures the daily light exposure, and accordingly adjusts the timing of the sleep-wake cycle. For this reason, daylight savings time and solar eclipses present challenges to our biological clocks.
The suprachiasmatic nuclei are connected to and stimulate the pineal gland which secretes the hormone melatonin at night. There are reciprocal nerve fibers that run from the pineal gland back to the hypothalamus providing a feedback loop that helps regulate homeostasis. If scientists cut the optic nerve conveying information from the retina to the brain, mice lose their normal circadian rhythms.
A key factor in how human sleep is regulated is exposure to light or to darkness. Exposure to light stimulates a nerve pathway from the retina in the eye to an area in the brain called the hypothalamus. When light enters the retina of the eyes, this signal is sent through the optic nerve to a region of the hypothalamus called the suprachiasmatic nucleus. This pathway is called the retinol hypothalamic tract. From the suprachiasmatic nucleus, nerve impulses via the sympathetic nervous system travel to the pineal gland and inhibit the production of melatonin. At night, these impulses stop (because no light stimulates the hypothalamus) and melatonin production. The hypothalamus controls body temperature, hunger, thirst, sleep, and circadian cycles. It is located above the brain stem. It links the nervous system to the endocrine system by way of the pituitary gland.
Nerve-signaling chemicals called neurotransmitters control whether we are asleep or awake by acting on different groups of nerve cells, or neurons, in the brain. Neurons in the brainstem, which connects the brain with the spinal cord, produce neurotransmitters such as serotonin and norepinephrine that keep some parts of the brain active while we are awake. Other neurons at the base of the brain begin signaling when we fall asleep. These neurons appear to block the signals that keep us awake. Adenosine begins to build up in our blood while we are awake and causes drowsiness. This chemical gradually breaks down while we sleep. Sleep regulatory circuits are controversial, but it is mainly believed that we continuously cycle through all five stages of sleep sometimes several times per night. Dreams are today's answers to tomorrow's questions. - Edgar Cayce
Brain waves are generated by the building blocks of your brain , that are the individual cells called neurons. Neurons communicate with each other by electrical changes. We can actually see these electrical changes in the form of brain waves as shown in an EEG scan. Brain waves are measured in cycles per second (Hertz; Hz is the short form). We also talk about the "frequency" of brain wave activity. The lower the number of Hz, the slower the brain activity or the slower the frequency of the activity.
REM/ NREM Sleep
During sleep, we usually pass through five phases of sleep. We spend approximately 50 percent of our total sleep time in stage 2 sleep, about 20 percent in REM sleep, (dream sleep), and the remaining 30 percent in the other stages. Infants, by contrast, spend about half of their sleep time in REM sleep. There are two main categories of sleep. REM sleep is rapid eye movement sleep that is the deep sleep phases when we dream. NREM is non-rapid eye movement sleep which is considered our lighter sleep. Usually that's what we have right before we wake up. REM and NREM follow in certain intervals. Usually when you are sleeping, you begin at stage 1 and go through each stage until reaching REM sleep, and then you begin the cycle again. Each complete sleep cycle usually takes from 90 to 110 minutes. Your brain acts differently in each stage of sleep.
Stage 1 sleep- You experience drifting in and out of sleep, and you can be easily woken up. Your eye movement and body movements slow down. You may experience sudden jerky movements of muscles, known as myoclonic jerks. During this stage of sleep you may sometimes feel a sensation of falling. The sensation is caused by the motor areas of the brain being spontaneously stimulated. Stage 2-During this stage, eye movement stops and your brain waves become slower. There will also be brief bursts of rapid brain activity called sleep spindles. Stage 3- During stage 3 sleep it can be very difficult to wake someone up. If you are woken up during this stage, you may feel groggy and disoriented for several minutes. Stage 4- This stage of sleep is the second stage of deep sleep. In this stage of sleep it is also very difficult to wake someone up. Both stages of deep sleep are important for feeling refreshed in the morning. If these stages are too short, sleep will not feel satisfying. Stage 5- REM sleep is the sleep stage in which dreaming occurs. When you enter into REM sleep, your breathing becomes fast, irregular and shallow. Your eyes will move rapidly and your muscles become immobile. Heart rate and blood pressure increase. REM sleep is also the phase of sleep in which you dream. This sleep phase begins about 70 to 90 minutes after you fall asleep. The first sleep cycle has a shorter phase of REM sleep. Toward morning, the time spent in REM sleep increases and the deep sleep stages decrease.
‘ Top Down’, neural switches for sleep
Certain regions in the brain stem regulate sleep and wakeness in response to fatigue and diurnal rhythms. Neurons send Electrochemical signals through the hypothalamus, thalamus, and basal forebrain to the cerebral cortex during wakefulness. While the brain is in a wakeful state, the cerebrospinal accumulates proteins called sleep regulatory substances, (SRSs), which induces sleep. Neurons in the pons generate REM. These neu7rons send signals to the thalamus, which then communicates with the cerebral cortex. A small area of pons initiates a wave of changes in brain activity that start REM sleep.
A theory of sleep was proposed by scientists at Washington State University in 2008 that challenged the ‘top down’ model of sleep explanation. These scientists published an article that sleep occurs as an ‘emergent property’. It states that groups of neurons become tired and switch to low level activity, then other neurons follow like dominos and shut down. This theory easily explains a sleep talker, or walker, as those supporting neurons simply haven’t gone ‘offline’ yet.
Sigmund Freud's basic insight that our minds preserve memories and emotions which are not always consciously available to us has transformed the way humanity views itself ever since. Freud said that we are not in control of our own minds. The tendency of modern people to trace their problems to childhood traumas or other repressed emotions begins with Freud. One of Freud's more important discoveries is that emotions buried in the unconscious surface in disguised form during dreaming, and that the remembered fragments of dreams can help uncover the buried feelings. Whether the mechanism is exactly as Freud describes it, many people have derived insights into themselves from studying their dreams, and most modern people consider dreams emotionally significant. Freud argues that dreams are wish-fulfillments, and will ultimately argue that those wishes are the result of repressed or frustrated desires. The anxiety surrounding these desires turns some dreams into nightmares.
This site is a great resource that offers helpful information for a good nights sleep.
Annotated Bibliography ‘13 Dreams Freud Never Had’ by J. Allan Hobson M.D./(prologue), ISBN: 0-13147225-9 This book discusses the bizarre nature of dreams and the unconscious mind and it’s connection to our emotions. Each chapter maps how each individualized entry dream interpretation fits into the physical structure of the brain. ‘Emergence of Noise-Induced Oscillations in the Central Circadian Pacemaker’ PLOS Biology; Oct 2010, Volume 8, Issue 10, page 1-19 This article discusses a study done on mice focused on their chiasmatic nucleus and the effects of external noise to their mammalian circadian clock. ‘The Master Clock Becomes Servant’-Article by Brian Fiske Natures Neuroscience, Volume 6, Issue 2, page 108/ ISSN: 10976256 Discusses the suprachiasmatic nucleus (SCN), a specialized clock or pacemaker in the hypothalamus of mammals. Role of the SCN in regulating daily rhythms in behavior and body function; intrinsic mechanisms of the SCN. Academic Journal- Indian Journal of Medical Research/ ISSN: 0971-5916 This academic journal discusses two states of sleep that are non-rapid eye movement, (NREM), sleep that is divided into four stages, (1,2,3, and 4); and rapid eye movement sleep, (REM). http://www.youtube.com/watch?v=2fpVKb_X0uM&feature=player_detailpage – This website’s video overviews brain wave activity helpguide.org/life/sleep_tips.htm –This website overviews strategies to aide in healthy sleep. http://www.youtube.com/watch?v=CWMEnkyL_qA&feature=player_detailpage -This website’s video discusses Freud's basic insight that our minds preserve memories and emotions
Continued Annotated Bibliography National Sleep Foundation/ E-mail firstname.lastname@example.org ‘Anxiety, Phobias, and Panic Attacks- The All Natural Program’ (pg.198-199) –Douglas Hunt M.D./ ISBN: 0-446-69181 ‘Overview of Sleep & Disorders’ –by S. Chokroverty Indian Journal of Medicine; Volume 131, Issue 2, (page 126-140)/ ISSN: 09715916 This article defines sleep on the basis of dividing sleep into two stages, NRM,(which is divided into three stages, and REM sleep. This article discusses physiological body changes sleep, and the automatic and somatic nervous system. It also discusses sleep disorders. ‘Brain the Complete Mind’ (pages 190- 192), (page 188), (page 172) -Michael S. Sweeney/ ISBN: 978-1-4262-0547-7 ‘Anxiety, Phobias, and Panic Attacks- The All Natural Program’ (pg.198-199) –Douglas Hunt M.D./ ISBN: 0-446-69181 ‘Sleep and Dreams’ (page 41) , (page10), (pages 10-18), (pages 105-115), (pages 63-74)-by Faith Hickman Bryne /ISBN: 978-0-7613-2312-9 This book discusses the facts that scientist have discovered about sleep. It makes a clear point about sleep being a necessary force in our lives. Brynie helps shed some light on the physical, emotional, and social issues surrounding sleep and screams; and how these issues affect our lives.