Some of us feel well-rested after a solid eight hours of sleep. For others, closer to nine feels best. For others still, a little less will do. How much sleep we prefer to get is highly subjective -- but how much sleep we need is a bit more concrete.
我们中的一些人，睡足了8个小时后觉得无比神清气爽。对于另一些人来说，睡差不多9个小时为最佳。还有一些人，稍微不足这点时间刚刚好。我们更愿意睡多久是非常主观的——但是我们需要多少睡眠就是有那么一点具体有形的了。

After web analytics showed the vast popularity of the How Much Sleep Do We Really Need? feature of the National Sleep Foundation's (NSF) website, a panel of experts set about to reassure that the information provided there was the most accurate and up to date.
网络分析显示，由国家睡眠基金会网站发起的“我们到底需要睡多久”非常受欢迎，并且专家组开始着手确定上面提供的信息，它们是最为精确的，而且是最新的数据。

To do so, a panel of six sleep experts and 12 other medical experts from organizations including the American Academy of Pediatrics, the American Geriatrics Society, the American Psychiatric Association and the Society for Research in Human Development, conducted a formal literature review. The panel focused on the body of research surrounding sleep duration in healthy human subjects that had been published in peer-reviewed journals between 2004 and 2014. From the 312 articles reviewed, the experts were able to fine-tune existing sleep duration recommendations as detailed below:
专家组来自美国儿科学会、美国老年医学会、美国精神医学学会、人类社会发展研究这些组织的6名睡眠专家和另外12位医学专家，拟定了一份正式的文献综述。专家组专注于2004年到2014间发表的同行评议学术期刊上，健康人体的睡眠时间议题。从312篇的文献综述中，专家们得以调整已有的睡眠时长推荐，归结具体如下。

Newborns (0-3 months): 14-17 hours
新生儿（0-3个月）：14-17个小时

Infants (4-11 months): 12-15 hours
婴儿（4-11个月）：12-15小时

Toddlers (1-2 years): 11-14 hours
刚学会走路的孩子（1-2岁）：11-14个小时

Preschoolers (3-5): 10-13 hours
学龄前儿童（3-5岁）：10-13个小时

School-Age Children (6-13): 9-11 hours
学龄儿童（6-13岁）：9-11个小时

Teenagers (14-17): 8-10 hours
青少年（14-17岁）：8-10个小时

Young Adults (18-25): 7-9 hours
青壮年（18-25岁）：7-9个小时

Adults (26-64): 7-9 hours
成年人（26-64岁）：7-9个小时

Older Adults (65+): 7-8 hours
老年人（65岁以上）：7-8个小时

“This is the first time that any professional organization has developed age-specific recommended sleep durations based on a rigorous, systematic review of the world scientific literature relating sleep duration to health, performance and safety,” Charles A. Czeisler, Ph.D., M.D., professor of sleep medicine at Harvard Medical School and chairman of the board of the National Sleep Foundation, said in a statement.
“这是第一次有专业的组织，拟写一份年龄划分的睡眠时长推荐表，其基于的是严谨的，系统的检阅全球关于健康、性能和安全考虑的睡眠时长科学文献，”查尔斯·A·斯勒医学博士——哈佛医学院睡眠治疗的教授，同时也是国家睡眠基金会理事会的董事长在一份声明里说道。