Americans are not famous for self-deprivation, but experts say we consistently fail to get a good night's sleep. The recommended daily requirements should sound familiar: eight hours of sleep a night for adults and at least an hour more for adolescents. Yet 71 % of American adults and 85% of teens do not get the suggested amount. “Sleep is sort of like food,? says Robert Stickgold, a cognitive (认知的）neuroscientist at Harvard Medical School But, he adds，there's one important difference: “You can be quite starved and still alive, and I think we appreciate how horrible that must be. But many of as live on the edge of sleep starvation and just accept it”
Part of the problem is that we are so used to being sleep deprived and coping with that condition that we no longer notice how exhausted we really are. In 2003, sleep expert David Dinges at the University of Pennsylvania School of Medicine tested the effects of restricting sleep to eight, six, or four hours a night for two weeks. During the first few days, subjects sleeping less than eight hours admitted to being tired and lacking alertness. But by Day 4, most people had adapted to their new baseline sleepiness and reported feeling fine— even as their cognitfve performance continued to decline- Over time, they became so exhausted that they had difficulty concentrating on evea the simplest tasks. “The human brair. k only capable of about sixteen hours of wakefulness a day，” says Dinges. “When you get beyond that, it can't function as efficiently accurately or well.”
In the real worlds people overcome their sleepiness by drinking coffee or taking a walk. But then they find themselves nodding off in meetings or worse, behind the wheel, Those short snatches of unconsciousness are what researchers call microsieep, a sure sign of sleep deprivation, “If people are falling asleep because ‘the office was hot'or‘the meeting was boring,' that's not coping with sleep loss. I would argue that they're affecting their productive capabilty, says Dinges.
What most people don't realize is that the purpose of sleep may be more to rest the mind than to rest the body. Sleep helps strengthen memory, improve judgment, promote learning and concentration, boost mood, speed reaction time and sharpen problem solving and accuracy. According to Sonia Ancoli-Israel, a psychologist at the University of California who’s done extensive studies in the aging population, lack of sleep may even resemble the symptoms of dementia (痴呆)。In recent findings, she was able to improve cognitive function in patients with mild to moderate Alzheimer's simply by treating their sleep disorder. “The need for sleep does not change a lot with age,” says Ancoli-Israel, but often because of illnesses and the medications, “the ability to sleep does. ”
If you lack sleep, there’s plenty you can do to pay back your sleep debt. For starters，take your mom's advice, and get to bed early. If you can’t manage to sleep longer at. night，try to squeeze in a midday nap. Timothy Roehrs, director of research at the sleep Disorders and Research Center at Henry Ford Hospital advises against oversleeping on weekend mornings to make up for a workweek of deprivation; later rising can make it even harder later to get a full night s rest.
According to Dinges, the most common reason we deprive ourselves of sleep is work. Bat consider that in giving up two hours of bedtime to do more work，you5re losing a quarter of your recommended nightly sleep and gaining just 12% more time during the day. What if you could be 12% more productive instead? If mental sharpness is your goal, the answer is clear: stop depriving yourself, and get a good night's sleep.
65.We can learn from Dinges' experiment that .
A. sleeping less than 8 hours won't cause physical discomfort
B. people get easily used to lack of sleep in less than 4 days
C. people tend to ignore the decline in mental sharpness
D. people can keep themselves awake for only sixteen hours 65- In 66.Paragraph 3, the author shows that a person who is sleep deprived .
A. remains productive by drinking coffee or taking a walk
B. fails to cope with sleep loss through nodding off
C. engages in microsieep to maintain productivity
D. fells asleep due to the high temperature and boredom
67. The underlined word “that” in Paragraph 3refers to .
A. microsleep B.sleep deprivation
C.the hot office room D. the boring meeting
68. According to psychologist Sonia Ancoli-Israel, .
A. the elderly don't need as much sleep as they used to
B. the ability to sleep is not affected by medications
C. sleep deprivation may look like the symptoms of dementia
D. people with Alzheimer’s cannot be treated for sleep disorders
69. What's the author's attitude to people’s acceptance of sleep deprivation?
A. Supportive. B. Ambiguous C. Cautious D‘ Worried
70. What is the author’s purpose in writing this article?
A. To raise people’s awareness of the hidden sleep deprivation.
B. To urge people to catch up on lost time for a good night's sleep.
C. To show the common phenomenon of sleep loss in America,
D. To explain the reasons why people accept sleep starvation.