英语阅读: 女性生物钟走得快

　　MICHELE NORRIS, host: Were going to hear now about a new study that confirms what some women have suspected about body clocks. The study shows that women run on a different and faster clock than men. Its published in the journal Proceedings of the National Academy of Sciences.

　　NPRs Richard Knox reports on some of the studys implications.

　　RICHARD KNOX: For years, surveys have shown that women more often identify themselves as early birds and more men call themselves night owls, although there are lots of exceptions. Studies have also found that women report insomnia much more often than men. The new study, done on 157 people, may explain why.

　　At a sleep lab in Boston, volunteers spent up to eight weeks in a windowless room with no idea what time it was in the outside world. That allowed their inner clocks to drift according to each persons natural circadian rhythm.

　　Jeanne Duffy of Brigham and Womens Hospital is a study author.

　　Dr. JEANNE DUFFY : What we found was that the cycle length of the biological clock in women was shorter on average than it was in men. And the average difference was about six minutes.

　　KRULWICH: Now, she concedes that six minutes doesnt sound like much. But imagine you have a watch that runs six minutes too fast. If you didnt reset it, youd get more and more out of sync with the 24-hour cycle that we all have to live by.

　　We all have to set our biological clocks each day because none of us has an inner clock thats set to exactly 24 hours. If it was, we couldnt adjust to seasonal differences in night and day.

　　What the study found is that mans biological clocks tend to run slower and womens faster. In fact, some women - more than one in three - have inner clocks that run especially fast. They complete a daily cycle in less than 24 hours.

　　Ms. DUFFY: If your cycle length is shorter than 24 hours, you need evening light to keep you synchronized.

　　KNOX: And darkness in the morning. Thats just the opposite of people whose inner clocks run on a cycle thats longer than 24 hours. They need a daily dose of morning light to reset their biological clocks.

　　Maybe the biggest implication of the study is that there may be millions of women who fight every day against their inner clock to do what they need to do.

　　Dr. CHARLES CZEISLER: : I definitely think that thats happening out there.

　　KNOX: Thats Dr. Charles Czeisler, the studys senior author.

　　Dr. CZEISLER: I think many women are chronically sleep-deprived because their work obligations, theyre taking care of children, helping them with homework whatever is only be done in the evening hours precludes many women from getting to bed early enough to get a full, sound night of sleep.

　　KNOX: A lot of women can identify with that. But Czeisler also says many women dont see their early-to-bed, early-to-rise tendency as a problem.

　　Dr. CZEISLER: There are many women who really enjoy the fact that they can get up at 4:00 or 5:00 in the morning. They have peace and quiet. Before the rest of the world wakes up, they can get an extraordinary amount done, and they wouldnt trade it for the world.

　　KNOX: In fact, hes married to one, Dr. Theresa Shanahan.

　　Dr. THERESA SHANAHAN: I am a morning person. It is a special time in the day that I enjoy, and get up and always have.

　　KNOX: Shanahan says shes at her most productive when the rest of her family is still in bed.

　　Dr. SHANAHAN: Its wonderful when Ive accomplished four or five hours of work and the others are just waking up. Like, Ive had a good jump on the day.

　　KNOX: Her husband likes to stay up late.

　　Dr. CZEISLER: Im definitely an evening type.

　　KNOX: So how does it work, an early bird married to a night owl? You might think they dont spend much time together.

　　Dr. SHANAHAN: But if Im more rested, I am much easier to communicate with. I have, you know, more energy, have a more positive, I think, outlook.

　　KNOX: So she says their time together is more likely to be quality time. Czeisler says when they first got married, he didnt realize they were circadian opposites.

　　Dr. CZEISLER: We were so much in love that, you know, we probably didnt even notice the time of day.

　　KNOX: But theyve worked it out. Their 18th anniversary is later this month.

　　Richard Knox, NPR News, Boston.

　　昼夜节律 生命活动以24小时左右为周期的变动。又称近日节律。发光菌的发光，植物的光合作用，动物的摄食，躯体活动，睡眠和觉醒等。人体生理功能，学习与记忆能力、情绪、工作效率等也有明显的昼夜节律波动。昼夜节律与人类的活动关系密切。生理节律遭扰乱，会导致食欲下降、工作效率降低、事故增多；施用药物时间不同，疗效也不相同；毒物作用时间不同，其毒性表现也不一样；肿瘤细胞对X射线的敏感性也有昼夜差别。一般来说，人类的生命力以午夜最低。

　　苹果公司iPhone平台上推出了一款分析人体生理节律的应用，人体生理节律。有人说生理节律是伪科学，不过这些都是供大家娱乐的，不必太当真。