Our natural sleep cycle | Jessa Gamble

譯者: Marie Wu 審譯者: Adrienne Lin

Let's start with day and night.

我先從日夜談起，

Life evolved under conditions

生命的演進是在

of light and darkness,

光照與黑暗中進行，

light and then darkness.

也就是日出而後日落。

And so plants and animals

植物和動物因此而發展出

developed their own internal clocks

他們自己的內部時鐘，

so that they would be ready for these changes in light.

好讓自己熟悉這種光線的變幻。

These are chemical clocks,

這種化學激素時鐘，

and they're found in every known being that has two or more cells

可以在我們所知的每一種多細胞生物、

and in some that only have one cell.

甚至單細胞生物中觀察得到。

I'll give you an example --

我來舉個例子，

if you take a horseshoe crab off the beach,

如果你從海灘上抓走一隻大螃蟹，

and you fly it all the way across the continent,

讓它坐上飛機到大陸的另一端，

and you drop it into a sloped cage,

把它放進一個斜的籠子裡，

it will scramble up the floor of the cage

它會在它家鄉岸邊

as the tide is rising

漲潮的時間裡，

on its home shores,

爬上籠子較高的那一端，

and it'll skitter down again right as the water is receding

然後在數千哩之外的海水退去之時，

thousands of miles away.

又滑下籠子底部。

It'll do this for weeks,

它會重覆這種行為好幾個星期，

until it kind of gradually loses the plot.

直到它漸漸搞不清楚身處何地為止。

And it's incredible to watch,

這很不可思議，

but there's nothing psychic or paranormal going on;

但不是什麼靈異或超自然現象，

it's simply that these crabs have internal cycles

只是這些螃蟹的內部時鐘

that correspond, usually, with what's going on around it.

能與週遭環境相配合而已。

So, we have this ability as well.

人類也有這種能力，

And in humans, we call it the "body clock."

人類稱這種能力為生理時鐘。

You can see this most clearly when you take away someone's watch

當你拿走某人的手錶，把他關進一個

and you shut them into a bunker, deep underground,

深入地底的地堡裡，好幾個月不出來，

for a couple of months. (Laughter)

你就會清楚看到生理時鐘的作用。

People actually volunteer for this,

有些人還自願被關進地堡裡，

and they usually come out

當他們從地堡出來時，

kind of raving about their productive time in the hole.

對自己能清醒工作的時間總是胡吹一通。

So, no matter how atypical these subjects would have to be,

不管他們說的有多離譜，

they all show the same thing.

有一件事是確定的，

They get up just a little bit later every day -- say 15 minutes or so --

就是他們每天都會越來越晚起床，假設是晚15分鐘好了，

and they kind of drift all the way around the clock like this

然後就把整個生理時鐘往後推延，

over the course of the weeks.

在他們待在地堡期間內不斷推延。

And so, in this way we know that they are working on their own internal clocks,

我們發現，他們是依照自己的生理時鐘在運作，

rather than somehow sensing the day outside.

而不是靠感覺外面的日照在運作。

So fine, we have a body clock,

好，我們有生理時鐘，

and it turns out that it's incredibly important in our lives.

對我們的生命無比重要，

It's a huge driver for culture

也是文化的重要推動力量，

and I think that it's the most underrated force on our behavior.

我認為這是我們的行為裡，最被忽略的一股力量。

We evolved as a species near the equator,

人類是從接近赤道的地方開始發源，

and so we're very well-equipped

所以我們很能適應

to deal with 12 hours of daylight

有12個小時的白天

and 12 hours of darkness.

和有12個小時的夜晚。

But of course, we've spread to every corner of the globe

但現在，人類已分散居住在世界上每一個角落，

and in Arctic Canada, where I live,

在我居住的加拿大極地附近，

we have perpetual daylight in summer

夏天是永晝，

and 24 hours of darkness in winter.

冬天則是永夜。

So the culture, the northern aboriginal culture,

所以在北方的原住民文化裡，

traditionally has been highly seasonal.

傳統上是高度倚賴季節變化的。

In winter, there's a lot of sleeping going on;

冬天，人們睡覺的時間很常，

you enjoy your family life inside.

也都待在屋內享受家庭生活；

And in summer, it's almost manic hunting

而在夏天，有無止盡的狩獵

and working activity very long hours,

與工作活動，持續時間很長，

very active.

非常活躍。

So, what would our natural rhythm look like?

那麼，人類自然的時間韻律該是什麼樣子？

What would our sleeping patterns be

理想的人類睡眠

in the sort of ideal sense?

又該呈現什麼模式？

Well, it turns out

我們發現，

that when people are living

當人們的生活裡

without any sort of artificial light at all,

完全沒有人工光源時，

they sleep twice every night.

每天晚上會有二次睡眠週期，

They go to bed around 8:00 p.m.

他們會在晚上八點左右睡覺，

until midnight

直到午夜，

and then again, they sleep

接下來，

from about 2:00 a.m. until sunrise.

則從二點睡到日出時分。

And in-between, they have a couple of hours

在這二次睡眠之間，有好幾個小時

of sort of meditative quiet in bed.

是處於安靜的冥想階段。

And during this time,

在這段期間裡，

there's a surge of prolactin,

泌乳激素會大量分泌，

the likes of which a modern day never sees.

這在現代人身上是觀察不到的。

The people in these studies

參與這項研究的人指出，

report feeling so awake during the daytime,

他們在白天的時候感覺很清醒，

that they realize

是他們以前

they're experiencing true wakefulness

所沒有體會過的

for the first time in their lives.

清醒感覺。

So, cut to the modern day.

現在我們來談談現代人的生活。

We're living in a culture of jet lag,

我們的生活裡充斥著時差、

global travel,

全球旅行、

24-hour business,

24小時營業、

shift work.

輪班等現代文化，

And you know, our modern ways

現代人的

of doing things

工作方式，

have their advantages,

自有其優點存在，

but I believe we should understand the costs.

但我們得瞭解我們所付出的成本為何。

Thank you.

謝謝大家。

(Applause)

(掌聲)