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.

很多人稱清晨喝杯咖啡后，才能神清氣爽地開始工作。但最近研究人員發(fā)現(xiàn)，咖啡中的咖啡因帶來的“興奮效應(yīng)”很可能只是人們的心理作用而已。

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.

布里斯托爾大學(xué)最近的研究中，379名志愿者被要求在16個(gè)小時(shí)之內(nèi)不得服用任何咖啡因飲料，16個(gè)小時(shí)之后一組開始飲用咖啡因飲料，另一組以為自己飲用的也是咖啡因飲料，而實(shí)際上沒有。結(jié)果顯示，兩組志愿者的警覺興奮程度并沒有多大區(qū)別。

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."

“我們的研究表明，飲用咖啡因并沒有讓我們從中得到什么好處，”該研究首席顧問、布里斯托爾大學(xué)實(shí)驗(yàn)心理學(xué)專業(yè)教授彼得羅杰斯說道。

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.

但是為什么人們?cè)谇宄恳槐�咖啡后感覺確實(shí)不太一樣?研究人員稱，原因很可能是這杯咖啡扭轉(zhuǎn)了一夜沒有咖啡因供給所帶來的“疲憊效應(yīng)”。

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.

此項(xiàng)研究中，大約一半的志愿者不喝或者飲用很少量的咖啡因飲料，而另一半志愿者過去飲用此飲料較多。研究要求所有人進(jìn)行計(jì)算機(jī)測(cè)試以檢測(cè)他們的記憶力、注意力以及靈敏度。結(jié)果曾飲用較多的志愿者在飲用了假咖啡因飲料后，警覺度下降、更多人頭痛，以前很少飲用咖啡因飲料的志愿者則沒有出現(xiàn)這些現(xiàn)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".

在補(bǔ)充了咖啡因之后，出現(xiàn)不適癥狀的人群得以恢復(fù)，但靈敏度并沒有比其他人高多少。故而該研究證明了“咖啡因只能將人體機(jī)能帶回到正常狀態(tài)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.

據(jù)研究人員稱，此項(xiàng)發(fā)現(xiàn)不僅適用于愛喝咖啡者，同樣適用于清晨一杯茶才能使其投入工作的人群。