Even as much as a few ounces is enough to kill.

光是飲用幾盎司的水就足以致死。

The average healthy adult is made up of 55 to 60% water.

一般健康的成人由 55％ 到 60％ 的水組成。

The average baby, on the other hand, is roughly 75% water.

另一方面，一般的嬰兒由大約 75% 的水組成。

And that difference is why babies shouldn't drink water before they're at least six months old.

而這其中的差異，就是為什麼嬰兒不應該在六個月大之前喝水的原因。

Not from the tap or a well or a spring.

無論是從水龍頭、井水或是泉水。

Plain water is just plain off limits.

只要是水都不能喝。

You see, everyone's kidneys have a limit to how much water they can handle.

你知道每個人的腎臟對於能夠負荷的水量有限。

Break that limit, and the excess water will back up into your bloodstream, where it dilutes the salt, or sodium, in your blood.

一旦超過限制，那些過量的水便回流到你的血液中，稀釋在你血液裡的鹽分，鈉。

Once your blood dips below 0.4 ounces of sodium per gallon, you're at risk of a condition called Hyponatremia.

一旦你每加侖的血液裡含鈉低於 0.4 盎司，你將會面臨得到低鈉血症的風險 。

It happens when your cells try to return sodium levels to normal by absorbing the extra water and swell up like a water balloon in the process,

低鈉血症的發生是當你的細胞因為吸收多餘水分後嘗試恢復標準鈉含量，過程中細胞膨脹像一顆水球一樣。

causing complications like confusion, vomiting and muscle spasms.

引起的併發症有意識模糊嘔吐以及肌肉痙攣 。

Hyponatremia is common in marathon runners who drink too much too fast during a race without also providing enough sodium to balance out their blood.

低鈉血症好發於馬拉松跑者，他們在比賽當中短時間內攝取過多水分，卻沒有提供足夠的鈉以平衡他們的血液。

And if you keep drinking, that excess water will eventually reach the cells in your brain.

而如果你持續的喝，那些多餘的水分最終會影響你大腦的細胞。

By this point, you have a dangerous case of water intoxication, which affects roughly 200,000 Americans each year.

這時，你面臨一個危險的水中毒症狀，粗估每年約有 20 萬個美國人受到此症狀的影響。

It occurs when your brain cells swell, which builds up pressure inside your skull that can lead to seizures, brain damage, and, in severe cases, death.

水中毒的發生是當你的大腦細胞膨脹在頭骨內部產生壓力，這會導致癲癇發作、腦部損傷，最嚴重的情況是死亡。

But don't worry, dying from water intoxication is extremely hard for a fully-grown human.

不過不用擔心，對於一個成人來說要死於水中毒是相當困難的。

An adult would have to drink 2.5 to 5 gallons every few hours to reach that point.

一個成人必須每隔幾小時喝下 2.5 到 5 加侖的水才能夠達到致死的程度。

But for newborns, it's a different story.

不過對於新生兒來說就完全不同了。

Their kidneys are about half the size of an adult's, so they can't hold much water to begin with.

他們腎臟大小只有成人的一半，所以本來他們就不能夠喝很多水。

And it takes just a few ounces to cause problems.

只要幾盎司的水就能夠引發問題。

On top of that, their kidneys aren't developed enough yet to properly filter water, so any water that enters their body ends up in the circulatory system,

最重要的是，他們的腎臟由於尚未發展完全，不能夠適當的過濾水，因此任何進入他們身體裡的水分都會在循環系統中，

where it dilutes their blood and increases their water content by 7 to 8%.

稀釋他們的血液並增加他們水含量達 7-8 ％ 。

But it's not just drinking straight H2O that poses a threat.

不過也不只是直接喝水才會構成威脅。

In fact, most cases of water intoxication in infants don't even involve a glass of water.

事實上，大部分嬰兒水中毒的案件甚至不涉及到一杯水。

A common mistake is when people dilute baby formula too much by accident, or when parents dunk their infants up and down in a swimming pool,

最常見的錯誤是當人們不小心過度稀釋配方奶，或者是父母讓嬰兒上上下下的浸泡在游泳池當中，

and in the process the infant gulps in too much water.

而期間嬰兒吞下過多的水。

It's important that if your baby is showing signs of water intoxication that you take them to the hospital immediately,

非常重要的是當你的嬰兒出現水中毒的徵兆時，你必須立刻將他們送往醫院。

where a doctor will likely provide some form of fluids like intravenous saline solution to bring the infant's sodium levels up to normal.

醫生會提供某種像是靜脈注射生理食鹽水的液體，讓嬰兒的鈉含量恢復正常。