时差N小时:口臭是如何引起的?

Morning breath is a topic of many jokes, and a realboon to the mouth wash and toothpaste industries.But what exactly causes the foul taste and odor inyour mouth when you wake up in the morning? Themost basic answer to this question is gravity.

早晨醒来后的口气既是一个笑柄，又是许多漱口水和牙膏企业的福音。但究竟是什么让你在一觉醒来之后，嘴里充满了难闻又讨厌的味道呢?这一问题的实质却在于地球引力。

If you've eaten fewer than three hours before you go to sleep, your stomach hasn't had time todigest all of your food. When you lie down, gravity causes the gastric juices that are busydigesting your food to come up into your throat. Because your airway and food pipe are side-by-side, they share an adjoining wall. Those gastric juices that have backed up in your food pipeactually permeate that wall and enter into your air pipe. These juices can irritate your larynx,and cause your voice to be hoarse and your breath to turn foul.

如果你吃了东西后不到三小时就上床睡觉了，那么你的胃就没有时间来消化所有的食物。当你躺下后，正在消化食物的胃液在引力作用下涌向你的喉咙。由于你的气管和食道是并排的，它们之间只有一层隔膜，所以当胃液流回食道时，实际上有部分胃液通过隔膜，渗透进了气管。正是这些胃液使你感到喉咙不适，并让你的声音变得沙哑，口气变臭。

In addition, gastric juices are acidic enough to burn the mucous membranes in your throat,resulting in a sore throat that occurs in the mornings, but lessens throughout the day. Morningmouth tends to worsen with age, because as you get older, the top of your esophagus, thethin tube that leads from the mouth to the stomach, loosens. With the softening of the top ofthis tube, gastric juices can more easily escape from the esophagus into the air pipe.

此外，胃液的酸性太强足以伤害到你的喉咙粘膜，导致早起时喉咙疼痛，不过一天下来这种疼痛会减轻。随着年龄的增长，早起时的口气会越来越重，这是因为随着年龄增大，你的食道顶部(也就是连接你的口腔和胃部的薄管)会变得越来越松。随着食道顶部越来越宽，胃液从食道进入气管也变得更容易了。

Another contributing factor to morning breath is infrequent swallowing during sleep.Swallowing allows us to keep our mouth relatively free from odor-producing bacteria. Butwhen we're asleep, these bacteria can thrive, contributing to the bad taste in our mouthwhen we wake up.

另一个造成早晨口气的重要原因就是在睡觉的时候偶尔咽唾液。吞咽使我们的口腔能够相对减少口臭引起的细菌。然而当我们睡熟时，这些细菌就会大量繁殖，因此我们醒来后的口气非常的难闻。