雅思阅读材料之小睡一个小时作用有多大？.docx

智课网IELTS备考资料 雅思阅读材料之小睡一个小时的作用有多大？ The average Briton gets six-and-a-half hours sleep a night, according to the Sleep Council. Michael Mosley took part in an unusual experiment to see if this is enough.  It has been known for some time that the amount of sleep people get has, on average, declined over the years.  This has happened for a whole range of reasons, not least because we live in a culture where people are encouraged to think of sleep as a luxury - something you can easily cut back on. After all, thats what caffeine is for - to jolt you back into life. But while the average amount of sleep we are getting has fallen, rates of obesity and diabetes have soared. Could the two be connected?  We wanted to see what the effect would be of increasing average sleep by just one hour. So we asked seven volunteers, who normally sleep anywhere between six and nine hours, to be studied at the University of Surreys Sleep Research Centre.  The volunteers were randomly allocated to two groups. One group was asked to sleep for six-and-a-half hours a night, the other got seven-and-a-half hours. After a week the researchers took blood tests and the volunteers were asked to switch sleep patterns. The group that had been sleeping six-and-a-half hours got an extra hour, the other group slept an hour less.  While we were waiting to see what effect this would have, I went to the John Radcliffe hospital in Oxford to learn more about what actually happens when we sleep.  In the Sleep Centre, they fitted me up with a portable electro-encephalograph, a device that measures brain wave activity. Then, feeling slightly ridiculous, I went home and had my seven-and-a-half hours of sleep.  The following day I went to discuss what had happened inside my head during the night with Dr Katharina Wulff.  The first thing she pointed out was that I had very rapidly fallen into a state of deep sleep. Deep sleep sounds restful, but du