Women who don't get enough sleep may get some extra pounds over year, according to a study.

    A study conducted on more than 68,000 middle-aged US women suggests that females who don't get enough sleep may end up adding some extra pounds over years. 

    Researchers followed 68,183 middle-aged women for 16 years and found that those who slept 5 hours or less per night were one third more likely to gain weight than those who slept for 7 hours.

    Moreover, researchers found that the weight gain was substantial with some women even gaining 33 pounds or more.

    The associations betweensleep durationand weight gain persisted even after controlling for factors such as physical activity and calorie consumption in both groups.

    The findings, presented earlier this year at a medical conference and published in the American Journal of Epidemiology, furthers the evidence that sleep habits affect a person's weight.

    The exact reasons for association between sleep duration and weight gain aren't clear but some research suggests that sleep deprivation alters hormones involved in appetite control and metabolism.

    Also it's possible that people who sleep fewer hours either eat more or, because of fatigue, and exercise less often.

    The research was led by Dr. Sanjay R. Patel of Case Western Reserve University in Cleveland.

    一項由68000多名美國中年女性參加的研究表明，長期睡眠不足的女性容易發胖。

    研究人員對68183名中年女性進行了長達16年的“跟蹤”調查，結果發現，每晚睡眠時間為5小時或不足5小時的女性發胖的幾率比每天睡7小時的女性高三分之一。

    此外，研究人員發現，有些女性的體重有較大幅度的增長，16年內增加了33磅甚至更多。

    即便是在控制運動量和熱量攝入等因素的情況下，睡眠不足仍是導致發胖的主要原因。

    這項研究結果是在今年年初的一個醫學研討會上提出來的，并在美國《流行病學》雜志上發表。研究結果進一步說明，睡眠習慣會影響體重。

    雖然其中的具體原因目前還不清楚，但已有研究表明，睡眠不足會改變體內影響食欲和新陳代謝的激素水平。

    也可能是因為睡眠時間不足的人吃得較多，或者因疲倦而很少鍛煉身體。

    這項研究的負責人是克利夫蘭凱斯西儲大學的桑賈伊·R·帕特爾博士。