睡眠好 记忆好

Studying for a big exam at school or a presentation at work, but don't forget to get a good night's sleep. Brain scientists report more evidence this week that sleep can improve your memory.

Researchers at Harvard and the University of Pennsylvania tested 60 healthy young adults to see how well they can remember and recite back pairs of words. Subjects first learned the word pairs, then took a 12-hour break before being tested to see how many they remember. The study found that subjects who were allowed to sleep during the break performed much better and had sharper memories than those who were kept awake.

The authors believe that when people sleep on it after learning something new, that sleep helps store the information better in the brain. They say this is a particularly important finding for our society which attempts to replace sleep to improve efficiency.

Taking a stimulant¹ to stay awake can help with alertness² in a short term, but people really need sleep to retain knowledge and function at their best.

With this Medical Minute, I'm Robinson Mocare, ABC News, New York.

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sleep on sth:to wait to make a decision until the next day,after you have rested and have more time to think 把问题放到第二天解决

1 stimulant   

n.刺激物，兴奋剂

参考例句：

• It is used in medicine for its stimulant quality.由于它有兴奋剂的特性而被应用于医学。
• Musk is used for perfume and stimulant.麝香可以用作香料和兴奋剂。

2 alertness   

n.警觉

参考例句：

• Alertness, calmness, courage: he could see them all in the youngster's face. 机警，镇定，胆量，都摆出在这年青人的脸上。 来自子夜部分
• We must maintain a military standard, an alertness, and never vary it. 我们必须保持军队的准则，应当随时注意，切勿随时变动。