# 咖啡因：研究到底说了什么

咖啡因作用于睡眠的时间远长于它让你清醒的时间，因此个人化的截止时间胜过任何经验法则。



## 全部研究

- **The effect of caffeine on subsequent sleep: a systematic review and meta-analysis** — Gardiner C, Weakley J, Burke LM, et al. (2023), Sleep Medicine Reviews 69:101764. 咖啡因使总睡眠减少约 45 分钟、睡眠效率下降 7%。若要避免影响，一杯咖啡（约 107 毫克）应在睡前约 8.8 小时，训练前剂量（约 217 毫克）约 13 小时。

- **Wake up and smell the coffee: caffeine supplementation and exercise performance — an umbrella review of 21 published meta-analyses** — Grgic J, Grgic I, Pickering C, Schoenfeld BJ, Bishop DJ, Pedisic Z (2020), British Journal of Sports Medicine 54(11):681–688. 咖啡因对耐力、力量和爆发力都有增益 —— 所以杠杆是时机，而不是戒断。

- **Coffee, caffeine, and sleep: a systematic review of epidemiological studies and randomized controlled trials** — Clark I, Landolt HP (2017), Sleep Medicine Reviews 31:70–78. 咖啡因延长入睡时间，减少总睡眠和深睡眠；敏感度因遗传和习惯性摄入而异。

- **A review of caffeine's effects on cognitive, physical and occupational performance** — McLellan TM, Caldwell JA, Lieberman HR (2016), Neuroscience & Biobehavioral Reviews 71:294–312. 咖啡因能补回因缺觉损失的表现，但无法超过休息充足时的水平 —— 没有白得的好处。

- **Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed** — Drake C, Roehrs T, Shambroom J, Roth T (2013), Journal of Clinical Sleep Medicine 9(11):1195–1200. 即使在睡前 6 小时摄入 400 毫克咖啡因，客观睡眠也减少了 1 小时以上，而受试者几乎毫无察觉。

- **Sustaining executive functions during sleep deprivation: a comparison of caffeine, dextroamphetamine, and modafinil** — Killgore WDS, Kahn-Greene ET, Grugle NL, Killgore DB, Balkin TJ (2009), Sleep 32(2):205–216. 缺觉之后，刺激物能修补警觉度，却无法恢复高阶判断力。

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这是对已发表研究的科普性总结，不构成医疗建议。筛查得分不是诊断。若得分偏高或身体不适，请咨询医生。

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