سؤال قراءة ستيب محلول — فهم التفاصيل (تدريب 5603)

(1) The idea that “everyone needs 8 hours of sleep” is untrue. Newborns spend nearly two-thirds of their day asleep, most adults no more than one-third. Age. related differences in average time spent sleeping are rivaled by differences in the normal amount of sleep among individuals at any age. Some people thrive with fewer than 6 hours of sleep per night; others regularly sleep 9 hours or more. Sleep patterns may be genetically influenced. When two researchers, Wilse Webb and Scott Campbell, checked the pattern and duration of sleep among fraternal and identical twins, only the identical twins were strikingly similar. (2) Whatever their normal need for sleep, some 10 to 15 percent of adults complain of insomnia - persistent problems in falling or staying asleep. True insomnia is not the occasional inability to sleep that we experience when anxious or excited. For a stressed organism, alertness is natural and adaptive. Moreover, from middle age on, sleep is seldom uninterrupted. Occasional awakenings become the norm, not something to fret over or treat with medication. (3) Sometimes people fret unnecessarily about their sleep. Scientists have learned to doubt people’s fretful sleep reports. In laboratory studies, insomnia complainers do get less sleep than others, but they typically overestimate, by about double, how long it took them to fall asleep, and they underestimate by nearly half how long they actually slept. Even if we’ve been awake only an hour or two, we may think we’ve had little sleep. because it’s the waking part we remember. When researchers awaken people repeatedly during the night, some recall having slept soundly. (4) The most common quick fixes for true insomnia - sleeping pills - can aggravate the problem. Both reduce REM sleep and can leave a person with next-day blahs. With continued use, one needs bigger doses to get an effect, and when the drug is discontinued, the insomnia may worsen. Scientists are searching for natural chemicals that are abundant during sleep and might be synthesized as a sleep aid without side effects. In the meantime, sleep experts offer other natural alternatives: • Relax before bedtime, using dimmer light. • Avoid caffeine (this includes chocolate) after late afternoon and avoid rich foods before bedtime. A glass of milk may help. (Milk provides raw materials for the nufacture of serotonin, a neurotransmitter that facilitates sleep.) Sleep on a regular schedule (rise at the same time even after a restless night) and avoid naps. A regular sleep schedule boosts daytime alertness, too, as shown in a recent experiment in which University of Arizona students slept 7.5 hours a night on either a varying or consistent schedule • Exercise regularly but not in the late evening. (Late afternoon is best.) • Reassure yourself that the temporary loss of sleep causes no great harm, certainly nothing worth losing sleep over. • If nothing else works, aim for less sleep; go to bed later or get up earlier. (5)More rare but also more severe than insomnia are the sleep disorders narcolepsy and sleep apnea. People with narcolepsy (from narco, “numbness, “and lepsy,” seizure”) suffer periodic, overwhelming sleepiness. This usually lasts less than 5 minutes but sometimes occurs at the most inopportune times, perhaps just after taking a terrific swing at a softball or when laughing loudly or shouting angrily. In severe cases, the person may collapse directly into a brief period of REM sleep, with its accompanying loss of muscular tension. Those who suffer from narcolepsy - 1 in 2000 people, estimates the Stanford University Center for Narcolepsy - must live with extra caution. (6)The National Heart, Lung, and Blood Institute reports that 1 in 25 people (mostly overweight men) suffer from sleep apnea - a treatable disorder that was unknown before modern sleep research. They intermittently stop breathing during sleep. (Apnea means “stopping respiration”) After an airless minute or so, decreased blood oxygen arouses the sleeper to awaken and snort in air for a few seconds. The process can repeat more than 400 times a night, depriving the person of slow-wave sleep. Apart from complaints of sleepiness and irritability during the day - and their friends’ complaints about their loud “snoring”- apnea sufferers are often unaware of their disorder. What percentage of adults have problems falling asleep?