Name: 【戶外百科】全民瘋爬山 | 體力再好也要小心高山症！How high altitude affects your body - Andrew Lovering
Uploaded: 2022-07-23T21:01:30.000Z
Duration: 5 min 12 s

("Human beings simply aren't built to function at the cruising altitude of a 747." - Rob Hall, "Everest", dir. by Baltasar Kormákur)

(「人類構造本質上無法在波音 747 的飛行高度運作。」- Rob Hall，《聖母峰》，Baltasar Kormákur 執導)

If someone teleported from sea level to the top of Mt. Everest, things would go bad fast.

如果一個人從海平面被即時傳送到聖母峰頂，一切都會快速惡化。

At an altitude of 8,848 meters, barometric pressure is approximately 33% of what it is at sea level.

在海拔 8,848 公尺的地方，氣壓大約是海平面氣壓的 33%。

This means there's significantly less oxygen in the air, and our teleported individual would likely suffocate in minutes.

這表示空氣中的氧氣顯著地變少，而被即時傳送到上面的人大概會在幾分鐘內窒息。

However, for people that make this same journey over the course of a month, it's possible to survive at the peak for hours.

然而，對於利用一個月完成同一旅程的人來說，在峰頂存活數小時是可能的。

So, what can happen to our bodies in just one month that allows us to endure this incredible altitude?

那麼，僅僅一個月內，我們的身體可能會發生什麼事，足以讓我們忍受那驚人的海拔？

Let's imagine you're one of the 5.8 billion people living less than 500 meters above sea level.

想想你是居住在海平面500公尺以上的 58 億人之一。

When you take a breath at this altitude, your lungs fill up with air composed of numerous gases and compounds.

當你在這個海拔吸氣時，你的肺部會充滿由數種氣體與化合物組成的空氣。

Most important among these are oxygen molecules, which bonds to the hemoglobin in your red blood cells.

其中最重要的是氧分子，它們是與你紅血球中的血紅蛋白結合。

Blood then circulates throughout your body, bringing essential oxygen to all your cells.

血液接著會在你體內循環，將重要的氧氣送往你體內所有細胞中。

But as altitude increases, the air starts to get thinner.

但隨著海拔提升，空氣會開始變得稀薄。

The relative amounts of each compound remain the same well into the upper atmosphere, but overall, there is less oxygen for our bodies to absorb.

每種化合物相對的量儘管到了高層大氣也會維持不變，但整體而言，可以讓人體吸收的氧氣就比較少了。

And if you ascend to altitudes above 2,500 meters, the resulting oxygen deprivation can cause a form of altitude sickness known as AMS, often causing headaches, fatigue, and nausea.

而你如果繼續往上到海拔 2,500 公尺以上，接著發生的缺氧就可能引起一種被稱為 AMS 的急性高山症，通常會引起頭痛、疲倦以及噁心感。

Fortunately, AMS only happens when we ascend too fast because our bodies have numerous ways of adapting to high altitudes.

幸好，AMS 只會發生在我們上升太快的時候，因為我們的身體有應付高海拔的數種方式。

Within minutes or even seconds of reaching altitudes of 1,500 meters, carotid chemoreceptors in your neck sense your blood's low oxygen pressure.

在達到海拔 1,500 公尺的數分鐘，甚至是數秒內，你脖子的頸動脈化學受器就會感應到你血液中的低氧壓。

This triggers a response that increases the rate and depth of your breathing to counteract the lack of oxygen.

這會觸發一個反應，提高你呼吸的速率與深度以對抗缺氧狀況。

Your heart rate also increases and your heart contracts more tightly to pump additional blood with each beat, quickly moving oxygenated blood around your body.

你的心跳也會加速、心臟收縮程度則會更大，使得每次跳動都會傳出更多血液，讓有氧的血液快速地在體內流動。

All these changes happen relatively fast, and if you were to keep ascending, your heart rate and breathing would speed up accordingly.

這些變化的發生速度相對地快，而你如果要繼續往上爬，你的心跳速率以及呼吸速度也會相應地提升。

But if you stayed at this altitude for several weeks, you could reap the benefits of some longer-term adaptations.

不過你如果在這個海拔停留數週，你就可能獲得長期適應之下的好處。

Within the first few days above 1,500 meters, the volume of plasma in your blood decreases, which increases the concentration of hemoglobin.

在 1,500 公尺以上的前幾天，你血液當中的血漿量會減少，進而提升血紅蛋白濃度。

Over the next two weeks, your hemoglobin levels will continue to rise, allowing your blood to carry even more oxygen per milliliter.

在接下來的兩週，你的血紅蛋白指數會繼續上升，讓你每毫升血液中的氧含量更高。

Paired with your high heart rate, this new hemoglobin-rich blood efficiently distributes oxygen throughout your body.

這個全新的富血紅蛋白血液搭配高心跳速度將有效地將氧氣分送到你體內各處。

So much so that the volume of blood being pumped with each heartbeat can return to normal levels.

其程度之高足以使得每次心跳所送出的血液回覆到正常值。

Over this same time, your breathing also increases even further in a process called ventilatory acclimatization.

於此同時，你的呼吸會再進一步地加速，而這個程序就被稱為「呼吸適應」。

After this several weeks of extended acclimatization, your body has made enough significant changes to climb even higher.

在這數週的長期適應後，你的身體會發生足以讓你繼續攀登的顯著改變。

However, you'll still have to spend additional time acclimating along the way, often climbing back down to recover before ascending even higher.

然而，你在途中還是必須花費額外時間進行適應，通常涉及在爬更高前，先折返進行恢復。

Because the summit of Everest isn't just high, it's the highest place on Earth.

因為聖母峰頂不只是高而已，它是全世界海拔最高的地方。

And at altitudes above 3,500 meters, our bodies are under incredible stress.

在海拔 3,500 公尺以上時，我們的身體會承受極大的壓力。

Arteries and veins in the brain dilate to speed up blood flow, but our smallest blood vessels, called capillaries, remain the same size.

腦動脈以及腦血管會擴張以加速血液流動，但我們最微小、稱為毛細管的血管會維持同樣的尺寸。

This increased pressure can cause blood vessels to leak and fluid to build up in the brain.

這個增加的壓力可能引起血管破裂並使得液體在腦中堆積。

A similar issue can occur in the lungs, where low oxygen causes blood vessels to constrict, leading to more leaking vessels and fluid build-up.

同樣的問題也可能發生在肺部，低氧量可能引起血管收縮，導致更多的血管破裂與液體堆積。

These two conditions, known as HACE and HAPE, respectively, are incredibly rare, but can be life-threatening if not dealt with quickly.

這兩個症狀分別被稱為 HACE 與 HAPE，兩者都極為罕見，但如果沒有及時處理，可能會威脅性命。

Some Tibetans and South Americans with family histories of living at high altitude have genetic advantages that can prevent minor altitude sickness, but even they aren't immune to these severe conditions.

有些西藏人與南美洲人的家族歷史當中，曾有居住在高海拔的成員，讓他們發展了基因優勢，可以避免輕微的高山症，但就連他們也不會對這些嚴重症狀免疫。

Yet despite these risks, climbers over the last century have proved people can go higher than scientists ever thought possible.

然而儘管有這些風險，過去一世紀的登山客都已證明人類可能爬到比科學家預想還要高出許多的地方。

Pushing past their bodies' limitations, these climbers have redefined what humanity can adapt to.

這些登山客透過超越他們身體的極限，重新定義了人類可以適應的東西。

Next up, dig into the scientific mystery of motion sickness.

接著播出：探討動暈病這個科學謎團。

Why does one-third of the population suffer from it, and why haven't we figured a cure to this seemingly simple problem yet?

為什麼有三分之一的人口受它影響，以及我們為什麼還沒找到這個看似簡單問題的解藥？

Take a journey into the body to find out more with this video.

透過這部影片進行人體旅程以找出更多答案。