陳蕙雅思教材 - 雅思閱讀精選 (Sleep)

Sleep

Sleep is part of aperson's daily activity cycle. There are several

different stages ofsleep, and they too occur      in cycles.If you are an

average sleeper, yoursleep cycle is as follows. When you

first drift off intoslumber, your eyes will roll about a bit,your

temperature will dropslightly, your  muscles will relax, andyour

breathing       well slow and become quite regular.  Your brain waves slow down a

bit too, with the alpharhythm of rather fast       wavespredominating for the

first few minutes. Thisis called stage 1 sleep. For the next half hour or

so, as you     relax more and more, you will drift downthrough stage 2 and

stage 3 sleep. The loweryour stage of sleep, the slower your brain waves

will be. Then about 40 to60 minutes after you lose consciousness you will

have reached the deepestsleep of all. Your brain waves will show the large

slow waves that are knownas the delta rhythm. This is          stage4 sleep.

You do not remain at thisdeep fourth stage all night long, but instead

about 80 minutes afteryou fall into         slumber, your brainactivity level

will increase againslightly. The delta rhythm will disappear, to be

replaced by the  activity pattern of  brain waves. Your eyes will begin to

dart around under yourclosed eyelids as if you were   looking atsomething

occurring in front ofyou. This period of rapid eye movement lasts for some

8 to 15 minutes        and is called REM sleep. It is during REMsleep period,

your body will soon relaxagain, your breathing will grow     slowand regular

once more, and you willslip gently back from stage 1 to stage 4 sleep -

only to rise once again       to the surface of near consciousness some80

minutes later.

睡眠

睡眠是人每天日常活動迴圈的一部分。  人的睡眠分幾個階段，而這些階段也是迴圈發 生的。  如果你是一個正常的睡眠者，你的睡眠迴圈會這樣進行。  

在你開始昏昏入睡時，你 的眼睛會滾動幾下，體溫略有下降，肌肉放鬆，呼吸變得緩慢而有節奏。  除了開始幾分鐘 比較快的α節奏外，腦電波也稍有減緩。  

這被稱為第一階段睡眠。  在隨後約半小時內，你 進一步放鬆，進入第二和第三階段睡眠。  睡眠越深入，腦電波就越緩慢。  大約在開始睡眠 後的 40 到

60 分鐘，你將進入沉睡狀態。 這時的腦電波表現為巨大的緩波，被稱為δ節奏。 這就是第四階段睡眠。  但你並不是整夜都保持這種沉睡狀態。  入睡後約

80 分鐘左右，你 的大腦運動水準會再度略有提高。 δ節奏消失，並被腦電波的運動圖形取代。 你的眼睛會

在閉著的眼瞼下迅速轉動，就好象你在看著眼前發生的什麼事情。  這種迅速的眼球運動持 續約 8～15 分鐘，這一階段睡眠被稱之為快速眼動(REM)睡眠。

在 REM 睡眠階段，你的肢 體會很快再度放鬆，呼吸也再次放慢並變得有節奏，你會輕鬆地從第一階段滑入第四階段睡 眠-直到大約 80

分鐘後重新接近清醒狀態。