揭秘:女性为何在房事前感觉疲惫

　　It turns out women who say they are just too tired for sex may not be making excuses after all.

　　那些称自己太累而不愿同丈夫做爱的女性也许并不是在找借口。

　　According to a Harvard study, they run on a different biological sleep clock to men - and need to go to bed earlier because of it.

　　哈佛大学的一项研究发现，男性和女性的生物钟并不一致——女性习惯很早就寝就是因为这个原因。

　　According to the study, for many women their natural instinct is to go to bed early - so sex can be the last thing on their minds in the evening.

　　这篇研究报告称，早寝是女性的天性，这样她们就不用在做爱时考虑其他事情。

　　It's based on results produced by 157 people who spent eight weeks in a windowless sleep lab in Boston. They were isolated from all cues about the time in the outside world, allowing their body clocks to go back to natural circadian rhythms.

　　研究人员召集了157名志愿者，让他们在波士顿一个没有窗户的睡眠实验室里生活8个礼拜。在这个实验室里他们同外部世界完全隔绝，没有时间概念，这样他们的生物钟就能回归到最自然的状态。

　　Jeanne Duffy, one of the study's authors, told NPR: 'What we found was that the cycle length of the biological clock in women was six minutes faster on average than it was in men, making them much more likely to be early birds rather than night owls.'

　　珍妮 达芙是这项研究的发起人之一，她在接受美国国家公共电台采访时说：“试验中我们发现女性的生物钟平均要比男性的快6分钟，所以她们总是早睡早起。”

　　That six-minute variation can be further amplified by factors such as when light first hits the eye.

　　而光线等因素又会使这6分钟的差别继续扩大。