三次大规模的研究发现，每晚睡7小时左右的人寿命最长。日本研究者的最新研究报告中提到，他们在大约10年时间内跟踪调查了104,010位成年人。一开始，参与者回答了有关睡眠方式、健康状况、精神状况和生活习惯的问卷调查，这些因素都可能影响寿命。 分析了上述因素后，发现平均每天睡7小时的成年人的死亡率最低。令人惊讶的是，更少的睡眠时间，甚至少到每晚4小时，都不会显著提高男性的死亡率。而如果女性的平均睡眠小于4小时，她们的寿命则会缩短。但是睡眠时间超过7小时的成年人，特别是女性，很可能在10年内去世。
Three huge studies have found that people who sleep about seven hours a night live the longest. In the latest report from Japanese researchers, 104,010 adults were followed for about 10 years. At the start, the participants answered questionnaires about their sleep patterns, and about their health, mental status and lifestyle habits, which also can affect survival. After accounting for all of these factors, adults getting an average of seven hours had the lowest death rates. Surprisingly, less sleep, even as little as four hours a night, didn't significantly increase deaths for men and only lowered survival for women if they averaged less than four hours. But adults who slept longer than seven hours, particularly women, were more likely to die during the 10 years.
