31、你有没有鼻塞时总是只堵一个鼻孔的经历？（双语科普）

Why Does Your Nose Get Stuffy（堵塞） One Nostril（鼻孔） at a Time?

为什么你的鼻子总是会一次堵一个鼻孔？

Though you may not pay attention to it unless you're sick, you're always breathing more heavily from one nostril（鼻孔） than the other.

你一个鼻孔的呼吸总是比另一个鼻孔的呼吸更重，除非你生病了，否则你可能不会注意到这一点。

During the day, the sides switch and the other nostril goes into 'work mode', but why?

白天，两边的鼻孔会交替运作，其中一个鼻孔会进入“工作模式”，但这是为什么呢？

This process is automated（自动化的） by the aptly named autonomic nervous system（自主神经系统）, which is the same system that controls many things your body does all by itself such as digestion and heart rate.

这个过程是通过自主神经系统自动完成的，自主神经系统独自控制着你身体的许多方面，比如消化和心率。

For your nose, this system controls your 'nasal cycle', so that each nostril operates effectively.

对于你的鼻子来说，这个系统控制你的“鼻循环”，这样每个鼻孔都能有效地工作。

The nasal cycle happens, according to the US National Library of Medicine, several times during the day, and is only brought to your attention if your nose is clogged（阻塞） up more than usual.

根据美国国家医学图书馆的研究，鼻循环在一天中会发生好几次，只有当你的鼻子比平时堵塞得更厉害时才会引起你的注意。

In order to open one side of your nose and close the other, your body inflates（充气） tissue with blood.

为了打开你鼻子的一边并关闭另一边，你的身体会让血液充盈组织。

"Increased blood flow causes congestion（堵塞） in one nostril for about 3 to 6 hours before switching to the other side.

“血流量增加会导致一边的鼻孔堵塞约3至6小时，然后换到另一边鼻孔。

There is also increased congestion when one is lying down, which can be especially noticeable when the head is turned to one side," Jennifer Shu reports for CNN.

当一个人躺着的时候，堵塞感也会加强，尤其是当头转向一侧的时候，这种情况会特别明显。” 詹妮弗·舒在CNN的报道称。

It's believed that this cycle helps round out your sense of smell.

人们相信鼻循环有助于使你的嗅觉更加完整。

As Matt Soniak reports for MentalFloss, some smells are better picked up by fast moving air through your nose, while others take more time and are detected better with slow-moving air.

正如马特·索尼亚克在《心理牙线》杂志中所报道的那样，一些气味在快速流动的空气中更容易被鼻子捕捉，而另一些气味则在缓慢流动的空气中更容易被察觉，且则需要更长的时间。

If one side of your nose is wide open and the other is slightly closed, you get all of the smells.

如果你的鼻子一边大开着，另一边微闭着，你就能闻到所有的气味。

The process also gives each side of your nose a break, since a constant stream of heavily flowing air can dry it out and kill off the small hairs that protect you from foreign contaminants（外来污染物）.

这个过程也会让你的鼻子两边都得到休息，因为持续不断的强气流会使鼻子变干，对鼻腔中保护你免受外来污染物侵害的细小毛发造成损伤。

When you get sick, the whole process can become unbearable, because the one nostril that is effectively（其实） 'turned off' feels way, way more clogged than the other, Soniak says.

索尼亚克说，当你生病的时候，整个过程会变得难以忍受，因为你感觉一个其实“关闭”了的鼻孔比另一个更堵塞。

Basically, the clogged-up feeling is just amplified（加强） by the cold.

总的来说，感冒增强了这种堵塞感。

So the next time you feel like you're only breathing from one side of your nose,

所以下次当你觉得你只能用鼻子的一边呼吸时，

remember that it's a natural, automatic system working to keep you smelling properly, and to make sure your nose doesn't get dried out by a constant onslaught of dirty air.

记住这是与生俱来的自主系统，可以让你嗅觉保持良好，并确保你的鼻子不会被不断袭来的污浊空气吹干。