长久以来，每晚睡眠八小时一直被奉为最佳的养生信条。然而，科学研究表明，睡眠不足会导致认知能力下降、压力增加，长期缺乏睡眠更与认知衰退、精神疾病乃至早逝挂钩；而睡眠过多同样对健康不利。科学证据指向一个U型关系，即睡眠不足与睡眠过度都比适中的睡眠时长更为有害。2015年发表于《睡眠健康》的一项评估了575项研究的报告建议，18至64岁人群每晚应睡7至9小时，而65岁以上人群应睡7至8小时；另一项发表于《睡眠》的研究分析了311项研究，认为7小时是最佳目标。

今年5月13日发表在《自然》杂志上的一项最新研究，由哥伦比亚大学计算神经科学家温俊浩（Junhao Wen）领导，通过研究睡眠时长对人体特定器官“生物钟”的影响，进一步精确了睡眠范围。研究团队追踪了来自英国生物样本库等大型数据库中50万名成年人的睡眠时长与23种不同生物钟之间的关系。结果表明，大脑、肺、肝和皮肤等9个身体系统均呈现出U型规律。据此，女性的最佳睡眠时长为6.5至7.8小时，男性的最佳睡眠时长为6.4至7.7小时。

然而，人们不应过分拘泥于这些数字，因为将群体研究结果应用到个人身上十分复杂，而且因果关系难以厘清。睡眠质量、规律性和连续性同样重要，过度焦虑甚至会适得其反：美国睡眠医学学会2025年的一项调查显示，有76%的受访者曾因担心睡眠问题而失眠。专家建议，应多听从身体的声音，保证醒来时感觉精力充沛即可，通常将每晚睡眠目标设定在六至八小时之间，但无需为精确的数值而辗转反侧。

For a long time, sleeping eight hours a night has been received wisdom. However, scientific research shows that insufficient sleep causes cognitive decline and increased stress, with chronic deprivation linked to cognitive decline, psychiatric disorders, and early death; conversely, excessive sleep is also detrimental to health. Evidence indicates a U-shaped relationship, with both insufficient and excessive slumber being worse than an optimal middle range. A 2015 study in Sleep Health evaluating 575 studies recommended seven to nine hours of sleep for those aged 18 to 64, and seven to eight hours for those over 65, while another study in Sleep analyzing 311 studies concluded seven hours is the best target.

A recent study published in Nature on May 13th, led by Junhao Wen, a computational neuroscientist at Columbia University, refined these estimates by analyzing the effects of sleep duration on the "biological clocks" of specific organs. The team tracked the relationship between sleep duration and 23 different biological clocks across 500,000 adults, using databases like the UK BioBank. They discovered a U-shaped pattern across nine body systems, including the brain, lungs, liver, and skin. The findings suggest that the optimal sleep duration is 6.5 to 7.8 hours for women and 6.4 to 7.7 hours for men.

However, individuals should not obsess over these figures, as applying population-level data to individual lives is complex, and causality remains difficult to disentangle. Sleep quality, regularity, and continuity are also crucial, and excessive worry can backfire: a 2025 survey by the American Academy of Sleep Medicine found that 76% of respondents lost sleep due to worrying about sleep itself. Experts advise listening to one's body and sleeping enough to wake up feeling refreshed, generally aiming for six to eight hours a night without tossing and turning over the exact number.

Source: Is too much sleep as bad as too little?

Subtitle: The quest for the optimal amount of shut-eye

Dateline: Jul 02, 2026 06:23 AM