Women who fail to get enough shut-eye each night risk gaining weight, a Cleveland-based researcher reported.

    In a long-term study of middle-aged women, those who slept 5 hours or less each night were 32 percent more likely to gain a significant amount of weight (adding 33 pounds or more) and 15 percent more likely to become obese during 16 years of follow-up than women who slept 7 hours each night.

    This level of weight gain -- 15 kg, or 33 pounds -- is "very clinically significant in terms of risk of diabetes and heart disease," Dr. Sanjay Patel of Case Western Reserve University said.

    Women who slept 6 hours nightly were 12 percent more likely to experience major weight gain and 6 percent more likely to become obese compared with those who slept 7 hours each night.

    The 68,183 women in the study provided information in 1986 on their typical night's sleep and reported their weight every 2 years for 16 years.

    Women who said they slept for 5 hours or less each night, on average, weighed 5.4 pounds more at the beginning of the study than those sleeping 7 hours.

    After accounting for the influence of age and weight at the beginning of the study, women who slept 5 hours or less each night gained about 2.3 pounds more during follow-up than those who slept 7 hours nightly. Women who got 6 hours of shut-eye each night gained 1.5 pounds more than those who slept 7 hours nightly.

    The researchers analyzed the diets and physical activity levels of the women, but failed to find any differences that could explain why women who slept less weighed more. "We actually found that women who slept less, ate less," Patel said.

    "In terms of exercise, we saw a small difference in that women who slept less exercised slightly less than women who slept more but it didn't explain the magnitude of our findings," Patel said.

    All in all, it seems that diet and exercise are not accounting for the weight gain in women who sleep less, Patel concluded.

    It's possible that sleeping less may affect changes in a person's basal metabolic rate -- the number of calories burned when at rest, Patel said.

    Another possible contributor to weight regulation that's come to light recently is called "non-exercise associated thermogenesis" or NEAT, which refers to involuntary activity such as fidgeting or standing instead of sitting. It may be, Patel said, that if people who sleep less, also move around or "fidget" less.

    克利夫蘭研究人員說，在夜間缺乏睡眠的人很有可能增加體重。

    這項長期跟蹤中年婦女的調查顯示，每晚睡眠少于5個小時的婦女比睡眠足夠7個小時的婦女更容易變胖。大量增加體重（大約33磅或者更多）的比率要高出32%，16年后會走進肥胖人群的比率高出15%。

    凱斯西儲大學薩耶·帕特爾說15公斤或者33磅的體重增長在醫學上已經很可怕了，可能引起糖尿病和心臟病。

    每天晚上睡6個小時的婦女明顯增加體重的幾率比每晚睡7個小時的婦女要高出12個百分點，變肥胖的幾率要高出6個百分點。

    68183位婦女參加了此項調查，1986年報告了自己的夜間睡眠狀況，在之后的16年中，每兩年匯報一次體重狀況。

    初期調查顯示，每晚睡眠少于5個小時的婦女比7個小時的婦女平均體重多出5.4磅。

    除去年齡的影響和調查初期的體重增長情況，在之后的調查中發現睡眠少于5個小時的婦女比7個小時的婦女體重要多增加2.3磅。每晚睡6個小時的婦女比七個小時的多增加1.5磅。