咖啡提神实为心理作用

Many say their brains don't start working properly in the morning until they have had a cup of coffee. But the stimulating effect for which caffeine is famous for may be an illusion, say researchers.

很多人称清晨喝杯咖啡后，才能神清气爽地开始工作。但最近研究人员发现，咖啡中的咖啡因带来的“兴奋效应”很可能只是人们的心理作用而已。

In a study carried out by Bristol University recently, 379 people who abstained from caffeine for 16 hours before drinking either caffeine or a placebo (dummy drink) were tested for a range of responses afterwards. The researchers found little variance in levels of alertness among the volunteers.

布里斯托尔大学最近的研究中，379名志愿者被要求在16个小时之内不得服用任何咖啡因饮料，16个小时之后一组开始饮用咖啡因饮料，另一组以为自己饮用的也是咖啡因饮料，而实际上没有。结果显示，两组志愿者的警觉兴奋程度并没有多大区别。

Peter Rogers, from the university's department of experimental psychology and one of the leading authors of the study, said: "Our study shows that we don't gain advantage from consuming caffeine."

“我们的研究表明，饮用咖啡因并没有让我们从中得到什么好处，”该研究首席顾问、布里斯托尔大学实验心理学专业教授彼得罗杰斯说道。

But what makes people feel different after a cup of coffee in the morning? The researchers say that it is because it reverses the fatiguing effects of overnight caffeine withdrawal.

但是为什么人们在清晨一杯咖啡后感觉确实不太一样?研究人员称，原因很可能是这杯咖啡扭转了一夜没有咖啡因供给所带来的“疲惫效应”。

Around half the volunteers drank little or no caffeine and the other half were medium-high caffeine consumers. All were asked to carry out a series of computer tasks to test their level of memory, attentiveness and vigilance. The medium-high caffeine consumers who received the dummy drink reported a fall in alertness and an increase in headaches, neither of which were reported by those who received caffeine.

此项研究中，大约一半的志愿者不喝或者饮用很少量的咖啡因饮料，而另一半志愿者过去饮用此饮料较多。研究要求所有人进行计算机测试以检测他们的记忆力、注意力以及灵敏度。结果曾饮用较多的志愿者在饮用了假咖啡因饮料后，警觉度下降、更多人头痛，以前很少饮用咖啡因饮料的志愿者则没有出现这些现象。

However, their post-caffeine levels of alertness were no higher than those of no or low-level consumers who received a placebo. This suggests caffeine only brings coffee drinkers back up to "normal".

在补充了咖啡因之后，出现不适症状的人群得以恢复，但灵敏度并没有比其他人高多少。故而该研究证明了“咖啡因只能将*机能带回到正常状态而已”。

The researchers said their findings could also apply to those who claim they rely on a morning cup of tea to get their brains going.

据研究人员称，此项发现不仅适用于爱喝咖啡者，同样适用于清晨一杯茶才能使其投入工作的人群。