Sleep Laboratory, Department of Psychiatry, University of Edinburgh, Edinburgh, Scotland.
Br J Clin Pharmacol. 1974 Jun;1(3):203-8. doi: 10.1111/j.1365-2125.1974.tb00237.x.
1 The effect of caffeine alkaloid base (300 mg) on whole night sleep was investigated by electrophysiological techniques in six late middle age subjects (mean age 56 years), comparison being made with decaffeinated coffee and with no drink prior to sleep, using each condition five times in a balanced order on non-consecutive nights. 2 After caffeine the mean total sleep time decreased on average by 2 h, the mean sleep latency increased to 66 minutes. The number of awakenings increased and the mean total intervening wakefulness was more than doubled after caffeine. 3 In the first 3 h of sleep a decreased amount of stage 3 + 4 was observed, accompanied by an increased amount of stage 2 and of intervening wakefulness, without a significant change in the amount of rapid eye movement sleep. 4 The change in sleep pattern observed suggests an increased capability for arousal and decreased ability to develop or sustain deeper stages of non-rapid eye movement sleep after caffeine.
六位中老年受试者（平均年龄 56 岁）接受了 300 毫克咖啡因碱（caffeine alkaloid base）的整夜睡眠影响的电生理学技术研究，与脱咖啡因咖啡和睡前不饮酒进行了比较，每种情况在非连续的五个夜晚中以平衡的顺序进行五次。
咖啡因后，平均总睡眠时间平均减少 2 小时，平均睡眠潜伏期增加到 66 分钟。觉醒次数增加，咖啡因后平均总中间觉醒时间增加一倍以上。
在睡眠的前 3 小时观察到第三和第四阶段的数量减少，伴随着第二阶段和中间觉醒的数量增加，而快速眼动睡眠的数量没有明显变化。
观察到的睡眠模式变化表明，咖啡因后唤醒能力增加，发展或维持非快速眼动睡眠更深阶段的能力下降。
