Have you ever wondered why thinking too much makes you tired？ A new studyhas found out some answers to this question. Researchers from the Paris BrainInstitute looked at why mental1 effort makes us tired. They found that when peoplethink a lot， the brain releases a chemical called glutamate2. Too much glutamateupsets the brain’s functions. It means the brain tells the body it is tired and that itmust rest. People who spend more than six hours working on a task that requires alot of thought are more likely to feel tired. A period of rest allows the brain to returnto normal. This explains why a power nap3 is good for us.

你想過(guò)為什么過(guò)度思考會(huì)讓你感到疲憊嗎？一項(xiàng)新的研究已經(jīng)發(fā)現(xiàn)了這個(gè)問(wèn)題的一些答案。來(lái)自巴黎腦科研究所的研究人員研究了為什么腦力勞動(dòng)會(huì)使我們疲憊。他們發(fā)現(xiàn)，當(dāng)人們思考過(guò)多時(shí)，大腦會(huì)釋放一種叫做谷氨酸的化學(xué)物質(zhì)。太多的谷氨酸會(huì)擾亂大腦的功能。這意味著大腦告訴身體它已經(jīng)累了，它必須休息。在一項(xiàng)需要大量思考的任務(wù)上花費(fèi)六個(gè)小時(shí)以上的人更有可能感到疲憊。一段時(shí)間的休息可以使大腦恢復(fù)正常。這就解釋了為什么打一會(huì)兒盹對(duì)我們有好處。

The research team looked at the behaviour4 of 40 participants5 in theirresearch. 24 of them had to perform challenging tasks. These included looking at acomputer screen and matching different letters that appeared. The other 16participants did a similar， but easier task. Both teams worked for six hours， and hadtwo ten-minute breaks. The researchers scanned6 the brains of the participants. Theyfound that the group who had the more difficult task had higher levels of glutamatein their brain. Study author said， “It would be great to find out more about howglutamate levels are restored.”He asked， “Is sleep helpful？ How long do breaksneed to be to have a positive7 effect8？”

研究小組在研究中觀察了40 名參與者的行為。其中24 人必須執(zhí)行具有挑戰(zhàn)性的任務(wù)。這些任務(wù)包括看著電腦屏幕并匹配出現(xiàn)的不同字母。其他16 名參與者執(zhí)行了一個(gè)類似的，但更簡(jiǎn)單的任務(wù)。兩個(gè)小組都工作了六個(gè)小時(shí)，并有兩次時(shí)長(zhǎng)十分鐘的休息。研究人員對(duì)參與者的大腦進(jìn)行了掃描。他們發(fā)現(xiàn)，執(zhí)行更困難任務(wù)的小組人員大腦中的谷氨酸水平更高。研究作者說(shuō)：“如果能了解更多關(guān)于谷氨酸水平是如何恢復(fù)的真相就更好了?！彼麊?wèn)道：“睡眠是否有幫助？要多長(zhǎng)的休息時(shí)間才會(huì)產(chǎn)生積極的影響？”

（英語(yǔ)原文選自：breakingenglishnews.com）

▏Notes

1. mental. 思考的；精神的

2. glutamate. 谷氨酸鹽；谷氨酸酯

3. nap. 小睡，打盹

4. behaviour. 行為，舉止

5. participant. 參加者，參與者

6. scan. 掃描檢查

7. positive. 積極的，建設(shè)性的

8. effect. 作用，影響