Two major attributes of age-related sleep changes are earlier wake time and reduced sleep consolidation Dijk et al. A hallmark change with age is a tendency toward earlier bedtimes and wake times. Older adults approximately ages 65 to 75 typically awaken 1. There are no conclusive studies that demonstrate why older adults experience earlier wake times, despite decreased sleep efficiency, but one hypothesis may be an advanced circadian pacemaker that accompanies age Dijk et al.
It is unclear if this is due to older adults experiencing an increased sensitivity to light Dijk et al. Nonetheless, the consequences of an advanced circadian rhythm are a 1-hour advance in body temperature increase in the early morning and misaligned melatonin and cortisol secretion rhythms with the circadian clock Dijk et al. Younger adults may experience brief awakenings, but they are usually minor and occur close to an REM sleep transition; thus, sleep remains relatively consolidated.
Arousal occurring mostly from REM sleep in young adults suggests that there is a protective mechanism to keep from awakening during NREM sleep; however, this protective effect appears to also decline with age Dijk, As an individual ages between the ages of 20 to 60 , SWS declines at a rate of about 2 percent per decade Figure Dijk et al.
Because arousal thresholds are typically highest during SWS, and because SWS declines with age, older adults experience more frequent awakenings during a sleep episode.
Another important variable may be an age-related reduction both in homeostatic sleep pressure and circadian pacemaker effectiveness during the night Dijk et al. Although there have been few systematic studies, there appear to be gender-based differences in sleep and circadian rhythms. Available evidence is strongest in adults; however, gender differences have also been observed in infancy Bach et al.
In adults, men spend greater time in stage 1 sleep Bixler et al. Although women maintain SWS longer than men, they complain more often of difficulty falling asleep and midsleep awakenings. In contrast, men are more likely to complain of daytime sleepiness Ancoli-Israel, In women, the menstrual cycle may influence sleep-wake activity; however, methodological challenges have limited the number of conclusive findings Metcalf, ; Leibenluft et al.
For example, women often experience considerable daytime sleepiness during pregnancy and during the first few postpartum months, and as will be discussed in greater detail in Chapter 3 , they are also at a higher risk of developing restless legs syndrome Goodman et al.
Problematic sleep has adverse effects on all individuals, regardless of age; however, older people typically show an increase in disturbed sleep that can create a negative impact on their quality of life, mood, and alertness Ancoli-Israel, ; Bliwise, Elderly individuals sleep 36 percent less than children at age 5 Figure Although the ability to sleep becomes more difficult, the need to sleep does not decrease with age Ancoli-Israel, Difficulty in initiating and maintaining sleep is cited in 43 percent of the elderly Foley et al.
However, declining sleep efficiency and quality has also been observed in healthy older people Dijk et al. Changes in sleep patterns affect males and females differently. The progressive decrease in SWS is one of the most prominent changes with aging; however, it appears to preferentially affect men. Women ages 70 and older spend around 15 to 20 percent of total sleep time in stages 3 and 4; men of the same age spend only around 5 percent of total sleep time in stages 3 and 4 Redline et al.
Another gender contrast is that older women go to bed and wake up earlier than older men, which suggests that body temperature rhythms are phase-advanced in elderly women Campbell et al. However, both men and women have increased stage 1 and decreased REM sleep.
Older people also experience a decrease in melatonin levels, which may be due to the gradual deterioration of the hypothalamic nuclei that drive circadian rhythms Ancoli-Israel, The inability to maintain long sleep episodes and bouts of wakefulness may reflect, in addition to other medical factors, a continuously decreasing sleep homeostasis Dijk et al.
Other prominent factors are the continuous increase in sleep latency and nighttime awakenings and inconsistency of external cues such as light exposure which tends to be low , irregular meal times, nocturia, and decreased mobility leading to a reduction in exercise Dijk et al.
Turn recording back on. National Center for Biotechnology Information , U. Search term. Stage 2 Sleep Stage 2 sleep lasts approximately 10 to 25 minutes in the initial cycle and lengthens with each successive cycle, eventually constituting between 45 to 55 percent of the total sleep episode. Stages 3 and 4, Slow-Wave Sleep Sleep stages 3 and 4 are collectively referred to as slow-wave sleep SWS , most of which occurs during the first third of the night.
REM Sleep REM sleep is defined by the presence of desynchronized low-voltage, mixed-frequency brain wave activity, muscle atonia, and bursts of rapid eye movements Carskadon and Dement, Physiology During Sleep In addition to the physiological changes listed in Table , there are other body system changes that occur during sleep. Physiological changes also occur in the following systems: Cardiovascular: Changes in blood pressure and heart rate occur during sleep and are primarily determined by autonomic nervous system activity.
For instance, brief increases in blood pressure and heart rate occur with K-complexes, arousals, and large body movements Lugaresi et al. Further, there is an increased risk of myocardial infarction in the morning due to the sharp increases in heart rate and blood pressure that accompany awakening Floras et al.
Sympathetic-nerve activity: Sympathetic-nerve activity decreases as NREM sleep deepens; however, there is a burst of sympathetic-nerve activity during NREM sleep due to the brief increase in blood pressure and heart rate that follows K-complexes.
Compared to wakefulness, there is a rise in activity during REM sleep Somers et al. Respiratory: Ventilation and respiratory flow change during sleep and become increasingly faster and more erratic, specifically during REM sleep Krieger, ; Simon et al. Ventilation data during REM sleep are somewhat unclear, but they suggest that hypoventilation deficient ventilation of the lungs that results in reduction in the oxygen content or increase in the carbon dioxide content of the blood or both occurs in a similar way as during NREM sleep NLM, Further, during REM sleep, there is reduced rib cage movement and increased upper airway resistance due to the loss of tone in the intercostals and upper airway muscles Parker and Dunbar, More generally, ventilation and respiratory flow show less effective adaptive responses dur ing sleep.
Similarly, the arousal response to respiratory resistance for example, resistance in breathing in or out is lowest in stage 3 and stage 4 sleep Douglas, Cerebral blood flow: NREM sleep is associated with significant reductions in blood flow and metabolism, while total blood flow and metabolism in REM sleep is comparable to wakefulness Madsen et al. However, metabolism and blood flow increase in certain brain regions during REM sleep, compared to wakefulness, such as the limbic system which is involved with emotions , and visual association areas Madsen et al.
Renal: There is a decreased excretion of sodium, potassium, chloride, and calcium during sleep that allows for more concentrated and reduced urine flow.
The changes that occur during sleep in renal function are complex and include changes in renal blood flow, glomerular filtration, hormone secretion, and sympathetic neural stimulation Cianci et al. Endocrine: Endocrine functions such as growth hormone, thyroid hormone, and melatonin secretion are influenced by sleep.
Growth hormone secretion typically takes place during the first few hours after sleep onset and generally occurs during SWS , while thyroid hormone secretion takes place in the late evening. Melatonin , which induces sleepiness, likely by reducing an alerting effect from the suprachiasmatic nucleus, is influenced by the light-dark cycle and is suppressed by light Parker and Dunbar, Sleep-Generating Systems in the Brainstem Sleep process S is regulated by neurons that shut down the arousal systems, thus allowing the brain to fall asleep.
Wake-Generating Systems in the Brainstem Wakefulness is generated by an ascending arousal system from the brainstem that activates forebrain structures to maintain wakefulness Figure B. The Suprachiasmatic Nucleus The suprachiasmatic nucleus SCN is responsible for regulating circadian rhythms in all organs.
Sleep and Thermoregulation Body temperature regulation is subject to circadian system influence. Newborns and Infants At birth, sleep timing is distributed evenly across day and night for the first few weeks, with no regular rhythm or concentration of sleeping and waking. Young Children There are a limited number of studies that address normal sleep architecture in young children; however, one trend that appears to be consistent is that sleep amounts decrease as a child gets older.
Adolescents A complex and bidirectional relationship exists between pubertal development and sleep. Adults Sleep architecture continues to change with age across adulthood. Gender Differences Although there have been few systematic studies, there appear to be gender-based differences in sleep and circadian rhythms. Elderly People Problematic sleep has adverse effects on all individuals, regardless of age; however, older people typically show an increase in disturbed sleep that can create a negative impact on their quality of life, mood, and alertness Ancoli-Israel, ; Bliwise, Sleep, breathing, and cephalometrics in older children and young adults.
Part I: Normative values. Adair RH, Bauchner H. Sleep problems in childhood. Current Problems in Pediatrics. Ancoli-Israel S. Insomnia in the elderly: A review for the primary care practitioner. Sleep: Supplement. Sleep Research Society. Normal human sleep at different ages: Sleep in older adults; pp. Normal sleep in neonates and children.
In: Ferber RKM, editor. Principles and Practice of Sleep Medicine in the Child. Philadelphia: Saunders; Astrom C, Trojaborg W. Relationship of age to power spectrum analysis of EEG during sleep. Journal of Clinical Neurophysiology. Gender-related sleep differences in neonates in thermoneutral and cool environments.
Journal of Sleep Research. Activity and sleep in children with ADHD. Sleep and bedtime behavior in preschool-aged children. Nocturnal sleep and wakefulness: Effects of age and sex in normal sleepers. International Journal of Neuroscience. Cardiovascular variability after arousal from sleep: Time-varying spectral analysis. Journal of Applied Physiology. Bliwise D. Normal aging. Principles and Practice of Sleep Medicine.
Bunning E. The Physiological Clock. Berlin, Germany: Springer-Verlag; Modulation of endocrine function and metabolism by sleep and sleep loss. Sleep Medicine. Gender differences in the circadian temperature rhythms of healthy elderly subjects: Relationships to sleep quality.
Carskadon MA. The second decade. In: Guilleminault C, editor. Sleeping and Waking Disorders: Indications and Techniques. Carskadon M, Dement W. Normal human sleep: An overview. Philadelphia: Elsevier Saunders; Carskadon MA, Rechtschaffen A. Monitoring and staging human sleep. Pubertal changes in daytime sleepiness. Evolution of sleep and daytime sleepiness in adolescents.
In: Guilleminault CLE, editor. New York: Raven Press; Association between puberty and delayed phase preference. Noninvasive cardiovascular markers of acoustically induced arousal from non-rapid-eye-movement sleep.
Critical role of dorsomedial hypothalamic nucleus in a wide range of behavioral circadian rhythms. Journal of Neuroscience. Loss of integrative control of peripheral circulation during desynchronized sleep. American Journal of Physiology. Crick F, Mitchison G. The function of dream sleep. Sleep in infants and young children: Part one: Normal sleep. Journal of Pediatric Health Care.
Dement W, Kleitman N. Cyclic variations in EEG during sleep and their relation to eye movements, body motility, and dreaming. Electroencephalography and Clinical Neurophysiology: Supplement. Dement T, Kleitman N. The relation of eye movements during sleep to dream activity: An objective method for the study of dreaming.
Journal of Experimental Psychology. Dijk DCC. REM sleep as a gate to wakefulness during forced desynchrony in young and older people [abstract] Sleep. All night spectral analysis of EEG sleep in young adult and middle-aged male subjects. Neurobiology of Aging. Contribution of circadian physiology and sleep homeostasis to age-related changes in human sleep. Chronobiology International. Douglas NJ. Respiratory physiology: Control of ventilation.
A longitudinal study of sleep stages in young women during pregnancy and postpartum. Later endogenous circadian temperature nadir relative to an earlier wake time in older people. Chronobiology: Biological Timekeeping. Sunderland, MA: Sinauer Associates; Arousal and the circadian rhythm of blood pressure.
Clinical Science and Molecular Medicine Supplement. Sleep complaints among elderly persons: An epidemiologic study of three communities. Learning-dependent increases in sleep spindle density.
Circadian preference, sleep and daytime behaviour in adolescence. Gillette M, Abbott S. Fundamentals of the circadian system; pp. Restless leg syndrome in pregnancy. British Medical Journal. Sleep in normal late pregnancy. Polysomnographic sleep and waking states are similar in subsequent siblings of SIDS and control infants during the first six months of life.
Normal human sleep at different ages: Infants to adolescents; pp. Jones BE. Basic mechanisms of sleep-wake states.
Characteristics of sleep patterns during late pregnancy and postpartum periods. American Journal of Obstetrics and Gynecology. Longitudinal sleep patterns during pubertal growth: Four-year follow up. Pediatrics Research. Gender differences in the sleep of middle-aged individuals. Psychiatry and Clinical Neurosciences. Krieger J. Respiratory physiology: Breathing in normal subjects. Development of sleep patterns in early adolescence.
Effect of age on the sleep EEG: Slowwave activity and spindle frequency activity in young and middle-aged men. Brain Research. Longitudinal changes in fatigue and energy during pregnancy and the postpartum period.
Journal of Obstetric, Gynecologic, and Neonatal Nursing. Restless legs syndrome and sleep disturbance during pregnancy: The role of folate and iron. Effects of the menstrual cycle on dependent variables in mood disorder research. Archives of General Psychiatry. Cerebral states during sleep as studied by human brain potentials.
Breathing during sleep in man in normal and pathological conditions. Advances in Experimental Medicine and Biology. Human regional cerebral blood flow during rapid-eye-movement sleep.
Journal of Cerebral Blood Flow Metabolism. Cerebral O 2 metabolism and cerebral blood flow in humans during deep and rapid-eye-movement sleep. Time in bed, quality of sleep and school functioning of children. Differences in reported sleep need among adolescents. Nancyinocente yahoo. Como o sono leva a uma imobilidade de suas vidas dormindo. Divide- humanos. O sono se comportamentais. A cada momento do sono adormecido.
Ou seja, o sono se organiza em forma de ciclos. Sono e sonhos. Temas de medicina do sono. Sono e Envelhecimento. Revista de Psiquiatria do Rio Grande do Sul. Porto Alegre, v. Pular no carrossel. Anterior no carrossel. Explorar E-books. Os mais vendidos Escolhas dos editores Todos os e-books. Explorar Audiolivros. Os mais vendidos Escolhas dos editores Todos os audiolivros.
Explorar Revistas. Escolhas dos editores Todas as revistas. Explorar Podcasts Todos os podcasts. Explorar Documentos. Enviado por Jehonnes. Denunciar este documento. Fazer o download agora mesmo. Pesquisar no documento. Durmas bem: dicas para uma noite feliz. Anderson Guarnier da Silva. Danuska Tokarski. Eldenilson Monteiro. John Sue. Thiago Prates. Jefferson Andrade.
0コメント