But when it's cold, I want socks to keep my footsies warm!

但是，天氣冷的時候，我就會穿襪子讓自己保持溫暖！

Why do feet have so much thermal power!?

為什麼腳能夠這樣控制溫度呢！？

Howdy everybody! Thanks for watching D-News today. I'm Trace.

大家好！謝謝收看今天的 D-News，我是崔斯。

If you are watching this, you are warm-blooded.

如果你正在看這一段影片，那麼你是溫血動物。

Unless of course you are an alien, or a reptile that has learned to understand human speech… and, If so… then... hello.

除非你是外星人，或是聽得懂人類演說的爬蟲類… 如果是這樣的話… 那麼，嗯，嗨。

Warm-blooded animals have thermoregulation — we're constantly burning energy to keep our internal organs at optimal body temperature.

溫血動物有恆溫系統。我們燃燒能量以讓內部器官維持在最佳體溫。

Temperature is maintained by the burning of energy, but also sweating, shivering, and overall skin blood flow, and our feet and hands are major weapons in maintaining temperature.

體溫是透過燃燒能量來維持的，但是也會透過流汗、發抖和全身表皮層的血液流量來維持，然而，我們的腳和手是維持體溫最佳的武器。

Normally, blood runs from the heart, through arteries, vessels, capillaries and so on to cells and then back through veins to the heart again.

通常，血液從心臟流出，透過動脈、血管、微血管，到細胞然後經由靜脈再回到心臟。

When it's hot, things open up and blood flows more freely; and the opposite happens when it's cold.

體溫高的時候，血管擴張，血液流動比較順暢；相反地，體溫低，血液流動就比較慢。

The thing is, not all parts of the body are treated equally by the brain.

重點是，人腦並不是公平對待體內的每個器官。

In the 1930s, the cortical homunculus was created to describe how brains see our bodies.

1930 年時，皮質小矮人被創造出來讓我們可以更清楚地看到身體內部的運作。

Limbs aren't that important, and neither is the torso.

四肢和軀幹都沒有那麼重要。

So the input is largely ignored by the conscious mind; but, hands, lips, genitals and so on are very important!

因此大部分被省略；但是，手、嘴唇、生殖器等等就真的重要多了！

This model vogues with thermoregulation in some aspects as well.

這個模組在某些方面也模擬了人體的體溫調節功能。以我們的腳為例好了。

Our feet, for example, are often ignored by our brain, but are really important for thermoregulation!

腳通常會被忽略… 但是腳對於體溫調節是很重要的！

When you feel uncomfortably cold, the somatosensory cortex of your brain triggers to start thermoregulation.

當你覺得冷得不舒服的時候，大腦的體感皮層會啟動體溫調節功能。

It ups your body temperature by shivering, or opening blood vessels.

藉由發抖或血管擴張來調節體溫。

Inside the feet are arteriovenous anastomoses, which connect arteries directly to veins, bypassing all that capillary problem.

腳內的動脈和靜脈吻合，動脈緊緊連著血管，並經過微血管等等阻礙。

When you're warm, these vessels in your feet dilate which lets blood get all the way to your skin which regulates your temperature and cools you down.

當你覺得溫暖時，腳的血管會擴張，讓更多血液向前流向皮膚，來調節溫度，冷卻你的體溫。

This is why you put one foot out from under the covers.

這也就是你會把一隻腳伸到棉被外面的原因。

According to a spokesperson from the National Sleep Foundation, when you stick your foot out, those arteriovenous anastomoses allow the foot to cool you off, regulating your body temperature without disrupting your overall comfort.

根據國家睡眠基金會發言人的說法，當你把腳伸在棉被外時，動靜脈相連處會透過腳使你體溫下降，以不影響整體舒適感的方式調節你的體溫

Biology aside, thermoregulation also has to do with comfort.

撇開生物學不談，體溫調節也與舒適性有關。

Mom used to say most of your body heat was lost through your head and your feet.

媽媽總是說，身體裡大部分的熱是透過頭和腳散失的。

But that's actually a myth, sorry Mom.

但是在此要對媽媽說聲抱歉，這是個迷思。

The myth probably originated from the 1970s U.S. Army Survival Manual, where they said "40 to 45 percent of body heat" is lost through the head.

這可能源自 1970 年的美國。美國陸軍生存手冊上寫道，人體百分之 40 至 50 的熱是透過頭部散失的

Because the brain focuses on the head and chest for thermal comfort rather than the appendages and your feet.

大腦更注重頭部和胸部的溫度舒適性，

Chances are these regs were more concerned with keeping the soldiers happy; than their actual core body temperatures.

相較於其他部位而言。這些規章比較注重於讓士兵快樂，而不是真正的身體溫度調節。

In reality, a 2008 study in the British Medical Journal found heat loss is spread pretty evenly across the body, with only about seven to ten percent being lost through the head.

事實上，2008 年英國醫學雜誌研究發現，熱能散失是很平均地分佈在身體各部位，只有百分之 7 至 9 是由頭部散失。

But according to a 2009 paper from the University of Wollongong, most of that discomfort centers around the heat levels in our head, hands and face.

根據 2009 年臥龍崗大學的研究，大部份的熱的不舒適感集中在我們的頭部、手部以及臉部。

Perhaps because of that brain perception problem.

這可能是因為大腦的知覺問題。

Our poor downtrodden feet just get left in the dust.

我們可憐的受壓迫的腳就被拋在後頭了。

Our feet can get colder than our hands, our head or our chest, all without affecting our conscious discomfort levels.

我們的腳會比手、頭部或胸部還要來得冷，卻不致於影響我們感覺上的不舒適性。

Thus, it is the perfect candidate to thermoregulate while asleep.

因此，腳是睡眠期間最佳的體溫調節候選器官

Long story short, feet can be a bit cold and you will still be snug as a bug in a rug.

長話短說，腳會有點冷，而你還是會像地毯裡的小蟲一樣扒著棉被

What kind of crazy things do you do to get to sleep?

你睡覺時會做什麼瘋狂的事呢？

Maybe we'll do a video about how that works if you tell us them down in the comments.

也許我們來錄段影片關於你們這些行為，如果你願意留在下方評論區告訴我們。

Make sure you keep coming back to DNews every single day; subscribe so you get all our videos and we'll see you next time, sleep well.

請持續每天回來收看 DNews，並訂閱觀看所有我們影片。我們下次見，祝你好夢！