多久洗一次牀單最合適？

We spend more than a third of our lives in bed - but that place can quickly blossom into a "botanical park" of bacteria and fungus , according to New York University microbiologist Philip Tierno.
我們有超過三分之一的時間都待在牀上，但紐約大學的微生物學家菲利普·提艾諾表示，那裏可能會迅速變成細菌和真菌的“植物園”。

If left for too long, the microscopic life within the wrinkles and folds of our bed sheets can even make us sick, Tierno said.
如果牀單褶皺裏的微生物停留的時間太長，它們甚至會使我們生病，提艾諾說道。

To stem the invisible tide, he said sheets should be washed once a week.
他表示，爲了阻止這種暗藏的趨勢，我們應該一週洗一次牀單。

Humans produce roughly 26 gallons of sweat in bed every year. When it's hot and humid outside, this moisture becomes what scientists call an "ideal fungal culture medium."
人類每年在牀上會流下大約26加侖的汗水。當外面又熱又潮的時候，這些水分會變成科學家口中“理想的真菌培養基”

In a recent study that assessed the level of fungal contamination in bedding, researchers found that pillows between 1.5 and 20 years old can contain between four and 17 different species of fungus.
最近的一項研究檢測了牀上的真菌污染水平，研究人員發現，用了一年半的枕頭裏可能有四種不同的真菌，而用了二十年的枕頭裏可能有十七種不同的真菌。

And it's not just your own microbial life you're sleeping with. In addition to the fungi and bacteria that come from your sweat and skin cells, you also share your bed with foreign microbes.
你睡覺時藏在你周圍的微生物不僅僅來自你自身。除了你的汗液和皮膚細胞帶來的真菌和細菌，你的牀上還有外來的微生物。

These include animal dander, pollen, soil, lint and dust mite, to name a few.
舉幾個例子來說，這包括動物毛屑、花粉、土壤、纖維屑以及塵蟎帶來的微生物。

Tierno says all that gunk becomes "significant" in as little as a week. And unclean bedding still exposes you to materials that can trigger the sniffing and sneezing, since the microbes are so close to your mouth and nose that you're almost forced to breathe them in.
提艾諾表示，所有的這些討厭的微生物在一週的時間裏就會變得“不可忽略”。因爲這些微生物離你的鼻子和嘴那麼近，而不潔淨的牀上用品使你接觸到那些會讓你抽鼻子和打噴嚏的物質，你幾乎是被迫把那些微生物吸入了體內。

"Even if you don't have allergies per se, you can have an allergic response," Tierno said.
“即使你本身不過敏，你可能也會有過敏性反應，”提艾諾說道。

Another reason your sheets get dirty quickly has little to do with your behaviour or sweat patterns - the issue is simply gravity.
你的牀單很快就變髒的另一個原因與你的行爲或流汗關係不大，這只不過是引力的問題。

"Just like Rome overtime was buried with the debris that falls from gravity, gravity is what brings all that material into your mattress," Tierno said.
“就像重力會引起碎片的墜落，而超過一定時間，羅馬就會埋葬在這些碎片中一樣，重力也會把所有的那些物質帶到你的牀墊上，”提艾諾說道。

One to two weeks of this build-up is enough to leave anyone with a scratchy throat - especially those with significant allergies or asthma.(One in six Americans have allergies.)
這些物質積累一到兩週就足以讓任何人喉嚨沙啞，特別是那些有嚴重過敏症或哮喘的人。（六分之一的美國人都有過敏症。）

"If you touched dog poo in the street, you'd want to wash your hands," said Tierno. "Consider that analogous to your bedding.”
“如果你在街上碰到了狗便便，你就會想洗一下手，”提艾諾說。“你的牀上用品也是一樣的。”