求翻译：据估计，人们平均一晚需要7个半到8个半小时的睡眠。但有一些人可以睡得很少。比如，曾经有报道说撒切尔夫人在担任英国首相期间，每晚只睡4个小时。耶鲁大学心理学高级讲师吉尔.威尔金森指出，每天睡眠少于5和小时，甚至只有2个小时的健康个体非常少，但确实有这种人存在。睡眠的主要功能是使身体得到休息和补充，为机体修复和组织再生提供充足的时间。缺乏睡眠会使免疫系统受损，导致思维混乱、情绪消极、心情焦虑和性情急躁。是什么意思？

It is estimated that people take seven and a half to eight and a half hours of sleep per night. But some people can sleep very little. For example, there have been reports that he served as British Prime Minister, Mrs. Thatcher, slept only four hours per night. Yale University psychology senior lect

It is estimated that on average people need to be a night of 7 to 8 half-a-half-hour sleep. However, some people can sleep in a little. For example, it has been reported that Mrs Thatcher as prime minister of the United Kingdom in during each night, sleeping only 4 hours. senior lecturer at Yale Uni

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It is estimated that 7 for one night is the average one and a half to 8.5 hours of sleep. But some people can get very little sleep. For example, there was reported Lady Thatcher's tenure as United Kingdom Prime Minister, only slept 4 hours every night. Senior Lecturer in psychology at Yale Universi