But that is of course assuming that no major breakthroughs happen during your lifetime that can slow the process of aging, and that may be a very bad assumption.

當然前提是，在你的人生中沒有發生重大突破讓老化減緩，而這可能是個相當不好的假設。

There's a new series on National Geographic Channel which was developed with GE and the show's creators wanted to present my take on aging, so I'm here at the GE Global Research Centre to talk to principal scientist Dr. Fiona Ginty.

國家地理頻道與 GE(美國通用電氣公司) 合作推出新的系列節目，製作人想要拍我老化的過程，所以我正位在 GE 全球研究中心跟首席科學家 Fiona Ginty 博士對談。

And this would be kind of an example of, you know, one of the types of images we would generate, so...

- 這是一種樣本，其中一種我們製作的圖示種類，所以...

- What are we looking at here? - So these are our cells that are actively dividing, and these are cells that are heading on their way to death or apoptosis.

- 我們現在在看的是？- 這些是我們分裂旺盛的細胞，而這些是正邁入死亡或是凋亡的細胞。

Aging is not recognized as a disease. I mean, there are plenty of diseases we do acknowledge like diabetes, heart disease, Alzheimer's, and at their core, aging may be responsible for all of them.

老化並沒有被當成疾病，我的意思是，許多我們知道的疾病，如糖尿病、心臟病、阿茲海默症，核心來看，老化可能是造成這些問題的主因，

And yet aging seems natural because it's something that we do from birth and for a while it makes us better, bigger, stronger, faster, more intelligent.

然而老化卻看似自然過程，因為打從出生之後老化讓我們變得更好、更大、更壯、更快、更聰明。

But then at some point in your life, it reverses and aging makes our bodies decay and degrade. And why is that? Why do we have to age? Why do our bodies have to decay?

直到了你人生的某個時間點，老化轉變成讓我們身體衰敗退化的存在。為何會這樣？為何我們要老化呢？為何身體會衰敗呢？

Well, scientists are now realizing there is a fundamental cellular mechanism at the heart of aging.

科學家們如今了解到，細胞的老化有一套固有機制。

Do we age at the macroscopic level because our cells are aging at the microscopic level?

我們以肉眼可見的程度老化是因為我們的細胞以顯微程度在老化的關係嗎？

To a great extent, yes. There's only a finite number of times a cell will divide.

絕大部分，是的。一個細胞分裂的次數有限。

A key discovery was made by a biologist named Hayflick. He was studying normal human cells and what he found was that they can only divide a finite number of times, on average, it's about 50.

一位名叫 Hayflick 的生物學家有重大發現，當時他著手研究人類正常細胞，而他發現這些細胞的分裂次數有限：平均約 50 次。

Beyond that, the cell becomes senescent, which means it's an aged cell. It can divide no longer.

此外，那些細胞逐漸衰老，意思是這是老化的細胞，它無法再分裂。

It lives for a little while but it's the accumulation of these senescent cells in our bodies that leads to aging on the macroscopic scale.

它只活了一陣子，但正是這些累積在我們體內的衰老的細胞造成我們肉眼可見的老化。

So it's as though cells have this little timer inside them that tells them when to stop dividing. But how do they know, and what is that timer?

這就像是細胞裡面有個計時器告訴它們何時要停止分裂。但它們怎麼知道，還有那是怎樣的計時器？

- So, telomeres are like how your shoelaces have, you know, a little bit of plastic at the end to stop them from fraying.

- 端粒就像你的鞋帶上有的東西，一小段類似塑膠的東西附在尾巴防止鞋帶散開。

- So telomeres are like the ends of your shoelaces... - But for chromosomes? - But for chromosomes.

- 端粒就像是你鞋帶兩端的東西... - 只是是給染色體？- 沒錯，是給染色體。

So they keep the chromosome together and they stop it sticking to other chromosomes.

端粒子幫助染色體成型，以及防止染色體與其它染色體黏在一起。

So every time a cell divides, it loses some of the telomere. They estimate about 200 base pairs.

每當一個細胞分裂，它就會失去一些端粒子，經估算約有 200 對。

Why is that? Why can't it just copy to the end?

為何會這樣子？它無法好好複製到最後嗎？

You know, it's just sort of really the mechanics of it, you know, there's only so much space when DNA polymerase does its job of replicating. - When it's copying? - Yeah.

它就是這樣子的運作機制，那裡就只有那樣的空間讓 DNA 聚合酶進行複製工程。- 當它在複製時？- 是的。

So the telomere, and the telomere getting shorter is like your molecular clock. The cellular clock inside each cell that tells it how many times it has divided.

染色體逐漸變短，就像是你的分子時鐘，這個細胞時鐘告訴它已經分裂了多少次。

- Would you wana have your telomeres measured? - Well, people do get their telomeres measured.

- 你會想測量一下自己的染色體嗎？- 其實，人們的確需要量他們的染色體。

There have been associations made with lifestyle, with exercise, showing that longer telomeres are associated with a more active lifestyle, exercise.

跟生活型態、是否運動有關，較長的端粒跟較活躍的生活方式有關連，像是有運動。

What if there was a way to stop the telomeres from shortening? If we could do that, maybe the cells would live forever.

是否有方法能防止端粒變短？如果辦的到，或許細胞就能長存不死了。

- There's another enzyme involved called telomerase, and it keeps rebuilding, like, it doesn't let the telomere ever shrink, so it... - It rebuilds the telomere? - Right, exactly.

- 另有一種名叫端粒酶的酵素，它會不斷再生，不讓端粒變短，所以... - 它能重建端粒？ -沒錯。

There is one animal that doesn't seem to age, and that is the lobster.

有一種動物看起來都不會變老，就是龍蝦。

It just gets bigger over time. It doesn't get weaker and its chromosomes don't change. It has long telomeres that do not shorten, so it only dies when it gets eaten by something else, like us.

牠只會不斷長大，牠不會衰弱而且染色體也不會改變。牠有不會減短的長端粒，所以只會在被其他東西吃掉時才會死，比方說我們人類。

So how can we be more like a lobster?

所以我們能更像龍蝦那樣嗎？

Some people would say maybe, "I want my telomerase to be higher for longer." Would that help? I mean, would that keep us younger?

有些人會說：「我想要讓我的端粒更長。」那有幫助嗎？那會讓我們常保年輕嗎？

I mean it's balance because, you know, in cancer, you've got a perfect example of telomerase being active and it becomes an unregulated growth situation.

這是平衡，你們也曉得的，癌症就是端粒活躍的最佳範例，而它變成一種不規律的生長情況。

This is the double-edged sword of telomeres and telomerase.

這就是端粒和端力酶的兩面刃。

Cancer cells have really long telomeres, and they can divide indefinitely, and that is the problem with cancer: cancer is dividing cells that won't stop and they won't die.

癌細胞有相當長的端粒，而且它們能無限地分裂，這就是癌症問題所在：癌症是不停止分裂就不會死亡的分裂細胞群。

So, in a way, cancer is the immortal cell living within us.

某方面來說，癌症是住在人體內的不死細胞。

So maybe we've developed the aging process, maybe we have telomeres that shorten for a very good reason because otherwise, they could become cancerous.

因此或許我們已經發展出老化的過程，或許我們有很好的理由說明端粒會短少，因為若非如此，它們就會變得致癌。

So one of the theories there is that the cells divide that limited number of times because it stops them from accumulating damage that may be detrimental.

有個理論是，細胞有限次數的分裂，因為能防止它們累積對人體有害的損壞。

- So there is some... - It might cause them to become cancer. - Exactly.

- 所以有些... - 它可能造成癌症。 - 沒錯。

Over the past hundred years, developments in medicine have increased human lifespan more than we could have imagined, and I can only expect that the next hundred years will bring similarly incredible results.

過去百年間，醫藥的發達大大增加人類壽命到我們無法想像的程度，而我只能期盼在下一個百年會有一樣的驚人成果。

I'm not sure where or how they will take place, but you can bet that your life expectancy today will not be the actual age at which you die.

我不確定它們會在哪裡或如何發生，但你能打賭，現在你的預期壽命不會是你死亡時實際的年齡。

If you wanna find out more about the future of aging, well, then you should definitely check out the episode of Breakthrough which was directed by Ron Howard.

如果你想知道更多關於老化的未來，那麼你該看看由 Ron Howard 執導的 Breakthrough 節目。

That's airing on Sunday, November 29 at 9/8c. That is just one of six episodes of Breakthrough which was developed by National Geographic Channel and GE.

它會在 11 月 29 日星期日，東部時間地區 9 點， 中部時間地區 8 點播送。那是由國家地理頻道和 GE 製作的 Breakthrough 節目中的其中一集。

So, I wanna thank them for supporting Veritasium, and I wanna thank you for watching.

我想感謝他們對 Veritasium 的支持，也想感謝各位的觀看。

Oh, and I also made a video about the future of energy. It's over on the GE YouTube channel, so go check it out!

對了，我也製作了一部未來能源的影片。它在 GE 的 YouTube 頻道裡，去看看吧！