托福TPO閱讀真題及譯文：Breathing During Sleep

第一段：

托福TPO閱讀原文：
　　Of all the physiological differences in human sleep compared with wakefulness that have been discovered in the last decade, changes in respiratory control are most dramatic. Not only are there differences in the level of the functioning of respiratory systems, there are even changes in how they function. Movements of the rib cage for breathing are reduced during sleep, making the contractions of the diaphragm more important. Yet because of the physics of lying down, the stomach applies weight against the diaphragm and makes it more difficult for the diaphragm to do its job. However, there are many other changes that affect respiration when asleep.

托福TPO閱讀翻譯：
　　關(guān)于人類睡覺和清醒時生理狀態(tài)的差異在過去的十年里已被發(fā)現(xiàn)，在所有的這些差異中，呼吸系統(tǒng)控制方面的變化尤其引人注目。不僅是呼吸系統(tǒng)運作水平有差異，在如何運作方面也出現(xiàn)了變化。胸腔所做的呼吸運動在睡覺時會減少，使得橫膈膜的收縮變得更為重要。然而由于躺下來的物理作用，胃部壓迫橫膈膜使得橫膈膜難以工作。不管怎樣，睡眠時還有很多其他的變化影響著呼吸。

第二段：

托福TPO閱讀原文：
　　During wakefulness, breathing is controlled by two interacting systems. The first is an automatic, metabolic system whose control is centered in the brain stem. It subconsciously adjusts breathing rate and depth in order to regulate the levels of carbon dioxide (CO2) and oxygen (O2), and the acid-base ratio in the blood. The second system is the voluntary, behavioral system. Its control center is based in the forebrain, and it regulates breathing for use in speech, singing, sighing, and so on. It is capable of ignoring or overriding the automatic, metabolic system and produces an irregular pattern of breathing.

托福TPO閱讀翻譯：
　　清醒的時候，呼吸受到兩個互相影響的系統(tǒng)的控制。第一個是自動的新陳代謝系統(tǒng)，它的控制中心在腦干。它會潛意識的調(diào)整呼吸頻率和深度來控制二氧化碳和氧氣的濃度以及血液中的酸堿比。第二套系統(tǒng)是自發(fā)行為系統(tǒng)。它的控制中心在前腦，調(diào)節(jié)說話、唱歌、嘆息等行為時的呼吸。它能忽略或無視自動新陳代謝系統(tǒng)并且產(chǎn)生無規(guī)律的呼吸模式。哦~

第三段：

托福TPO閱讀原文：
　　During NREM (the phase of sleep in which there is no rapid eye movement) breathing becomes deeper and more regular, but there is also a decrease in the breathing rate, resulting in less air being exchanged overall. This occurs because during NREM sleep the automatic, metabolic system has exclusive control over breathing and the body uses less oxygen and produces less carbon dioxide. Also, during sleep the automatic metabolic system is less responsive to carbon dioxide levels and oxygen levels in the blood. Two things result from these changes in breathing control that occur during sleep. First, there may be a brief cessation or reduction of breathing when falling asleep as the sleeper waxes and wanes between sleep and wakefulness and their differing control mechanisms. Second, once sleep is fully obtained, there is an increase of carbon dioxide and a decrease of oxygen in the blood that persists during NREM.

托福TPO閱讀翻譯：
　　在NMER（睡覺時沒有快速眼部活動的階段）這個階段中，呼吸會變得更深更有規(guī)律，但是呼吸頻率會降低，導(dǎo)致總體空氣交換減少。發(fā)生這個是因為在NREM睡眠階段中，自動的新陳代謝系統(tǒng)會獨自控制呼吸，身體會利用更少的氧氣產(chǎn)生更少的二氧化碳。同時，自動的新陳代謝系統(tǒng)對血液中二氧化碳和氧氣的含量反應(yīng)并不靈敏。在睡眠中呼吸控制的變化會導(dǎo)致兩個結(jié)果。第一，睡著時呼吸可能會有短暫的停止或減少，因為睡眠者在睡眠和清醒之間徘徊，而這兩種狀態(tài)的控制系統(tǒng)不一樣。第二，一旦得到了充足的睡眠，血液中二氧化碳含量升高而氧氣含量降低，在NREM階段也會持續(xù)這樣。

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第四段：

托福TPO閱讀原文：
　　But that is not all that changes. During all phases of sleep, several changes in the air passages have been observed. It takes twice as much effort to breathe during sleep because of greater resistance to airflow in the airways and changes in the efficiency of the muscles used for breathing. Some of the muscles that help keep the upper airway open when breathing tend to become more relaxed during sleep, especially during REM (the phase of sleep in which there is rapid eye movement). Without this muscular action, inhaling is like sucking air out of a balloon—the narrow passages tend to collapse. Also there is a regular cycle of change in resistance between the two sides of the nose. If something blocks the "good" side, such as congestion from allergies or a cold, then resistance increases dramatically. Coupled with these factors is the loss of the complex interactions among the muscles that can change the route of airflow from nose to mouth.

托福TPO閱讀翻譯：
　　但這并不是全部的變化。在睡眠的所有階段中，氣道的一些變化已經(jīng)被觀察到了。睡眠時需要付出兩倍的努力去呼吸，因為呼吸道氣流的阻力會比較強并且用來呼吸的肌肉的效率會有變化。一些在呼吸時幫助保持上呼吸道通暢的肌肉在睡覺的時候會變得松弛，特別是在REM階段（就是有快速眼部運動的睡眠階段）。沒有這種肌肉運動，呼吸空氣就像從氣球里吸氣一樣，狹窄的通道會面臨崩潰。而且鼻子兩側(cè)的阻力也會周期性改變。如果有時候堵塞了“好”的一邊，比如過敏和感冒引起的堵塞，阻力就會大大增加。與這些因素一起的是那些能夠改變從鼻子到嘴巴的氣流路徑的肌肉之間失去了復(fù)雜的交互。

第五段：

托福TPO閱讀原文：
　　Other respiratory regulating mechanisms apparently cease functioning during sleep. For example, during wakefulness there is an immediate, automatic, adaptive increase in breathing effort when inhaling is made more difficult (such as breathing through a restrictive face mask). This reflexive adjustment is totally absent during NREM sleep. Only after several inadequate breaths under such conditions, resulting in the considerable elevation of carbon dioxide and reduction of oxygen in the blood, is breathing effort adjusted. Finally, the coughing reflex in reaction to irritants in the airway produces not a cough during sleep but a cessation of breathing. If the irritation is severe enough, a sleeping person will arouse, clear the airway, then resume breathing and likely return to sleep.

托福TPO閱讀翻譯：
　　其他呼吸調(diào)節(jié)機制在睡眠時顯然要停止運作。比如說，在清醒時如果呼吸變得困難的話就會有一個立即自動適應(yīng)性的呼吸增強（比如戴上面具呼吸）。但在NREM狀態(tài)時完全不存在這樣反射性的調(diào)節(jié)。在這種情況下，只有幾次不充分的呼吸后使得血液中二氧化碳的含量顯著提升以及氧氣的含量降低，呼吸才會被調(diào)整過來。最后，咳嗽反應(yīng)在應(yīng)對呼吸道中刺激物時產(chǎn)生的不是睡覺時咳嗽而是呼吸停止。如果刺激物足夠嚴(yán)重，睡著的人會醒來清理氣道，然后繼續(xù)呼吸很可能再度入睡。

第六段：

托福TPO閱讀原文：
　　Additional breathing changes occur during REM sleep that are even more dramatic than the changes that occur during NREM. The amount of air exchanged is even lower in REM than NREM because, although breathing is more rapid in REM,it is also more irregular, with brief episodes of shallow breathing or absence of breathing. In addition, breathing during REM depends much more on the action of the diaphragm and much less on rib cage action.

托福TPO閱讀翻譯：
　　發(fā)生在REM時期的多余的呼吸變化比發(fā)生在NREM時期的呼吸變化更顯著。REM的空氣交換量要比NREM低，因為盡管REM中呼吸更加急促，但也更加沒有規(guī)律，包括一些簡短的淺呼吸或呼吸暫停。另外，REM時期的呼吸更多取決于橫膈膜而不是胸腔的作用。