31. (阅读理解题)Sleepless nights don’t just ruin your mood the next day ― they could also damage your waistline. According to new research in the August issue of the American Journal of Clinical Nutrition, sleep deprivation can cause people to pack on extra pounds.

Researchers at the New York Obesity Nutrition Research Centre at St. Luke’s-Roosevelt Hospital found that sleep-deprived people seem to burn the same number of calories as the well-rested, but they consume about 300 more calories a day. Given that it takes just 3,500 calories to add a pound to your body, those calories can quickly turn into extra weight.
But there are several other reasons that sleep loss could lead to weight gain, says sleep disorder specialist Michael Breus. When we get too little shut-eye, our metabolism(新陈代谢)slows down to conserve energy. That slowdown triggers the release of the hormone cortisol (荷尔蒙皮质醇), which increases appetite. Your body thinks it needs more energy, so it asks for more food.
In a vicious cycle, sleep loss also causes our bodies to release more ghrelin(饥饿激素), another hormone that signals hunger working in the normal way, your body wants more food and lacks the sensitivity to know when to stop eating. Not to mention that being awake more hours gives you more time to snack.
“The later you’re up at night, the greater the likelihood that your’re going to eat,” Breus says, and “you’re more likely to eat high-fat, high-carb foods.”
One other contributing factor to such weight gain is that the body burns the most calories during REM sleep, a deeply restful phase. Less sleep means less time in REM.
For optimal health, experts say you should try to get 7.5 hours of sleep a night. If you have trouble sleeping, stick to a nightly routine, exercise during the day, banish worries to a journal, and keep pre-bedtime activities relaxing.
(1). (单选题) This passage is mainly about ______.(本题4.0分)
A、 the influence of sleep loss on weight
B、 The effect of sleep deprivation on mood
C、 the release of the hormone cortisol
D、 the implications of a new research finding
(2). (单选题) Sleep-deprived people consume more calories, which will ______.(本题4.0分)
A、 make them energetic
B、 turn into extra pounds
C、 damage their mood
D、 cause them to feel sleepy
(3). (单选题) According to Michael Breus, sleep loss can ______.(本题4.0分)
A、 decrease people’s appetite
B、 slow down energy conservation
C、 trigger the need for more food
D、 lead to a vicious cycle
(4). (单选题) The word “optimal” in the last paragraph is closest in meaning to ______.(本题4.0分)
A、 best
B、 positive
C、 optional
D、 appropriate
(5). (单选题) To attack sleep troubles, you can ______.(本题4.0分)
A、 exercise regularly at night
B、 do more pre-bedtime activities
C、 keep a journal at night
D、 follow a set routine every night

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