托福阅读:睡眠中呼吸的知识
时间:2021-09-09
来源:网络
作者:无
科学研究表示,人类不同年龄的睡眠时间是不同的。婴儿的睡眠时间为20~24小时,幼儿需要9~12小时,学童需要9~10小时,成人需要7~9小时,老年人需要6~8小时,大于80岁的老年人需要9~10小时。
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.
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.