日本高清色视频在线视频在,国产香蕉97碰碰视频碰碰看,丰满少妇av无码区,精品无码专区在线,久久无码专区免费看,四虎欧美精品永久地址99,亚洲色无码一区二区三区

首 頁(yè) | 新聞?dòng)⒄Z(yǔ) | 視聽(tīng)英語(yǔ) | 翻譯園地 | 實(shí)用英語(yǔ) | 專欄作家 | 奧運(yùn)英語(yǔ) | 新詞新譯 | 書友天地 | 輕松英語(yǔ)  | 凈臉聯(lián)盟 | 英語(yǔ)論壇 | 少兒英語(yǔ)
您現(xiàn)在的位置: En_language tips > 輕松英語(yǔ) > 一問(wèn)到底 Dec 26, 2005
 





  Why does caffeine keep me awake?

   
  Caffeine
   
  Why does caffeine keep me awake?
Caffeine interrupts our daily sleeping patterns by altering the chemical reactions in our brain.

An addictive drug that 90% of Americans consume every day, caffeine prevents us from getting our ZZZZs by increasing nerve activity in our bodies-keeping us alert and hyperactive.

After drinking a hot cup of caffeinated coffee, the caffeine causes three different chemical reactions that boost our energy levels:

It energizes us by pumping the hormone adrenaline into our systems.

It increases dopamine levels within our bodies. Dopamine is a neurotransmitter that stimulates our "pleasure areas" in our brain making us feel good.

It blocks the connection of adenosine to nerve cells. Adenosine is the chemical that attaches to receptors in the brain and causes drowsiness by slowing down nerve cells activity.

The addictive and mood altering effects caused by caffeine consumption has had an increasing impact on the soft drink industry. Over the past 25 years, the amount of soda consumed by Americans has doubled. For instance, Americans spent billion on 15 billion gallons of soda in 1998.

Today, 70% of all sodas in the United States contain caffeine. Teenagers especially have become dependent on caffeinated sodas or what many refer to as "liquid candy." Teenage boys and girls drink about twice as much "liquid candy" as milk, whereas twenty years ago they drank twice as much milk as soda.

While many soda companies argue that caffeine is necessary to a soft drink's flavor, many researchers have shown that most people are hooked to a soda's caffeine content-NOT its taste. Most people can't tell the difference between caffeinated and uncaffeinated soft drinks. Soda guzzlers prefer the soft drink brands that contain caffeine because the caffeine stimulates alertness and boosts of energy.

 

note:

 

 

 

hyperactive: 過(guò)分活躍的

 

 

hormone: 荷爾蒙
adrenaline: 腎上腺素

dopamine: 多巴寧(一種治腦神經(jīng)病的藥物)
neurotransmitter: 神經(jīng)傳遞素

adenosine: 腺苷
receptor: (感受刺激的)神經(jīng)末梢

 

 

 

 

 

 

hook: 沉迷, 上癮

 
 
 
Copyright by chinadaily.com.cn. All rights reserved
版權(quán)聲明:未經(jīng)中國(guó)日?qǐng)?bào)網(wǎng)站許可,任何人不得復(fù)制本欄目?jī)?nèi)容。如需轉(zhuǎn)載請(qǐng)與本網(wǎng)站聯(lián)系。
None of this material may be used for any commercial or public use. Reproduction in whole or in part without permission is prohibited.
<strong id="xdwva"><div id="xdwva"></div></strong>
<label id="xdwva"></label>

<thead id="xdwva"></thead>
    <label id="xdwva"></label>

  1. 日本高清色视频在线视频在,国产香蕉97碰碰视频碰碰看,丰满少妇av无码区,精品无码专区在线,久久无码专区免费看,四虎欧美精品永久地址99,亚洲色无码一区二区三区