Why do we breathe through one nostril?

為什麼我們只用一個鼻孔呼吸？

No idea.

不知道。

Our nostrils have specialized tissues.

我們的鼻孔有特別的組織。

At a given time, these tissues are swollen in one nostril while they are shrunk in the other.

在特定的時間，這些組織會在一個鼻孔中腫大，而會在另一個鼻孔中縮小。

Hence, when we breathe, air passes easily through the nostril in which the tissues are shrunk.

所以我們在呼吸的時候，縮小的鼻孔能順暢地呼吸。

However, due to the swelling, very less amount of air slowly passes through the other nostril.

不過由於腫大，另一個鼻孔就只能慢慢地呼吸到一點點的空氣。

Thus, it seems as if we breathing through one nostril only.

所以這就好像我們只從一個鼻孔呼吸。

However, after sometime, the swelling and shrinking in the nostrils reverses.

不過有時候，兩邊鼻孔的腫大和縮小會規律性的交換。

This breathing pattern is called nasal cycle.

這樣的呼吸方式稱之為鼻週期。

Nasal cycle is beneficial for us.

鼻週期對我們是有益的。

But how?

但是怎麼有益的呢？

Some odors are detected better in fast-moving air, while others in slow-moving air.

有些味道較能在快的氣流中聞到，不過其他的味道就會在較慢的氣流中聞到。

Thus, with fast moving air in one nostril and slow moving air in the other.

因此一個鼻孔是快的氣流，而另一個會是慢的氣流。

Our nose can detect a greater range of smells.

我們的鼻子可以嗅到很多的味道。

Besides this, our nostrils are moist.

除了此外，我們的鼻子是濕潤的。

Continues breathing can make them dry.

一直呼吸會讓他們乾燥。

Hence, when we breathe through one nostril, the other nostril gets time to become moist again.

因此當我們只用一個鼻孔呼吸時，另一個鼻孔就有時間再濕潤一次。