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研究人员发现，缺少睡眠会导致人体内饥饿荷尔蒙的增加，使孩子变得肥胖。

Sleep-deprived kids get fat

By Nanci Hellmich, USA TODAY

Children who don't get enough sleep are more likely to be overweight than those who get plenty of sleep, a study reports Wednesday.

This adds to a growing body of evidence that adequate sleep is important for weight control. Other research has revealed that sleep deprivation increases levels of a hunger hormone¹ and decreases levels of a hormone that makes people feel full.

About one-third of the children in the USA are overweight or obese², government data show.

Researchers at Northwestern University in Evanston, Ill., reviewed national data on more than 1,400 kids ages 3 to 12; follow-up data on the same children were collected five years later. The parents completed time diaries on children's bedtime and wake-up times. Children's height and weight were measured on two occasions.

The National Sleep Foundation recommends that preschoolers get 11 to 13 hours of sleep each night. Children ages 5 to 12 years are supposed to sleep 10 to 11 hours a night; teens, nine hours.

Findings in the journal Child Development:

?Many children aren't sleeping enough on weeknights: 10-year-olds slept an average of 9.5 hours a night; 14-year-olds, 8.5 hours; 17-year-olds, 8 hours.

?About 36% of children ages 3 to 8 who slept an average of 10 hours — too little for the small ones and barely enough for the older children — were overweight by middle school.

?Only 30% of children in that age range who got about 11 hours of sleep a night were overweight in middle school.

Overall, those who got an hour less sleep than their peers³ tended to be an average of 5 pounds heavier, says Emily Snell, a graduate student in human development and social policy at Northwestern. "Many kids have to get up at 6 a.m. or 7 a.m. to go to day care or school, so parents may want to put them to bed at 8 p.m. so they can get 10 or more hours of sleep a night," she says. A good night's sleep may help children achieve a healthy weight as well as improve their mood and school performance, she says.

University of Chicago sleep researcher Eve Van Cauter says it's possible these children are hungrier because of changes in appetite⁴ and fullness hormones.

"It's also quite possible that when (children are) really tired, they are less likely to go outside and play or engage in a sport, and they may be more likely to slouch⁵ in front of the television.

Notes:

1.  hormone [‘hR:mEun] n..荷尔蒙，激素。

2.  obese [Eu’bi:s] adj. 肥胖的，肥大的。

3.  peer [piE] n. 同龄人，伙伴。

4.  appetite [`Apitait] 食欲，胃口

5.  slouch [slautF] v. 懒散。