实用大学英语综合教程1课件孙新法 王慧ISBN 9787566307644 PPTUnit 4.ppt

Text Appreciation the debt be repaid. We dont seem to adapt to getting less sleep than we need; while we may get used to a sleep-depriving schedule, our judgment, reaction time, and other functions are still impaired. 2 People tend to sleep more lightly and for shorter time spans as they get older, although they generally need about the same amount of sleep as they needed in early adulthood. About half of all people over 65 have frequent sleeping problems, such as insomnia, and deep sleep stages in many elderly people often become very short or stop completely. This change may be a normal part of aging, or it may result from medical problems that are common in elderly people and from the medications and other treatments for those problems. Text Appreciation Experts say that if you feel drowsy during the day, even during boring activities, you havent had enough sleep. If you routinely fall asleep within 5 minutes of lying down, you probably have severe sleep deprivation, possibly even a sleep disorder. Light sleeps, or very brief episodes of sleep in a somewhat awake person, are another mark of sleep deprivation. In many cases, people are not aware that they are experiencing light sleeps. The widespread practice of “burning the candle at both ends” in western industrialized societies has created so much sleep deprivation that what is really abnormal sleepiness is now almost the norm. 4 Many studies make it clear that sleep deprivation is Text Appreciation dangerous. Sleep-deprived people who are tested by using a driving simulator or by performing a hand-eye coordination task perform as badly as or worse than those who are intoxicated. Sleep deprivation also magnifies alcohols effects on the body, so a fatigued person who drinks will become much more impaired than someone who is well rested. Driver fatigue is responsible for an estimated 100,000 motor vehicle accidents and 1500 deaths each year, according to the National Highway Tr