Rise and shine! Come on!

太陽曬屁股了，快起床！

Maybe your friend who wakes up at 5 a.m. every day is, like, kind of quirky, but I bet they're productive.

也許你認為那個每天 5 點起床的朋友有點古怪，但我肯定他們是很有工作效率的。

Your friend who wakes up [at] 11 every day, like, what do you think about them?

至於你那個 11 點才起床的朋友，你對他有什麼樣的評價？

But it turns out, sleeping late isn't just a preference or a bad habit.

原來睡到很晚並不只是一個偏好或壞習慣。

Research is showing that our bedtime could be coded into our DNA.

研究顯示我們的睡眠時間可能是由我們的 DNA 決定。

Each of us has an internal clock, but my clock isn't necessarily in sync with yours.

每個人都有自己的內部生理時鐘，但我的生理時鐘和你的不見得會同步。

That's because we all have our own chronotype, or preferred sleeping pattern.

那是因為我們都有自己的晝夜節律，或偏好的睡眠模式。

Scientists study chronotypes by tracking when people go to sleep on days when they don't have to go to work or to school.

科學家藉由研究人們在不用上班或上學的睡眠時間來分析他們的晝夜節律。

This chart shows the mid-point of people's sleep on those free days.

這個表格顯示人們在假日的晝夜節律平均值。

If you go to bed around 11 p.m. and get up around 7 a.m., you have an average chronotype.

如果你在 11 點就寢，並在 7 點左右起床，那你的晝夜節律就屬於平均值。

A very small number of people on either end of the chart have either very early or very late chronotypes.

在這個表格的兩個端點，是少部分的人們有極早或極晚的晝夜節律。

But even those of us who are just slightly behind the average chronotype can wake up feeling jet-lagged every day.

但即使是那些稍晚於晝夜節律平均值的人，每天醒來時也可能感受到時差。

If you have an average chronotype, you're generally getting the same amount of sleep on both free days and work days.

如果你屬於平均的晝夜節律，你在假日和工作日的睡眠時數是差不多的。

So, your sleep schedule fits with society's schedule.

所以你的睡眠時程和整個社會的運作相契合。

But the later your chronotype, the bigger the difference between the amount of sleep you get on free days versus work days.

如果你的晝夜節律越晚，你在假日和工作日的睡眠時間就差越多。

So, going back to a work after a free day can feel like flying over several time zones.

所以在假日隔天回去上班時，就會像飛過幾個時區那樣疲憊不堪。

And to understand why, you need to look at the master clock in our body.

為了了解為什麼有人會晚睡，你必須要觀察自己體內的生理時鐘。

It's a bundle of neurons called the "suprachiasmatic nucleus", or SCN.

這是由一束稱為「視交叉上核」，或簡稱 SCN 的神經元所組成。

If you have a normal chronotype, your SCN tells the pineal gland to start producing melatonin around 9 p.m. that makes you sleepy.

如果你的晝夜節律是正常的，你的 SCN 會告訴你的松果體在晚上 9 點左右開始製造讓你想睡的褪黑激素。

Around 10:30, your colon starts suppressing bowel movements.

在 10 點 30 分左右，你的結腸開始抑制腸胃蠕動。

Your body temperature drops to its lowest point around 4:30 a.m., and your blood pressure reaches its highest point around 6:45 a.m., so you're at your most alert around 10 a.m.

你的體溫在凌晨 4 點 30 分左右降到最低點，然後你的血壓在 6 點 45 分之間升到最高點，使你在 10 點左右最為清醒。

But for people with late chronotypes, all this stuff happens later in the day, and there's not much they can do about it.

但對較晚晝夜節律的人來說，這些流程都發生得較晚，而他們也束手無策。

That's because inside the neurons that make up the SCN, scientists have discovered something called "clock genes".

這是因為在組成 SCN 的神經元中，科學家們發現了一個稱為「時鐘基因」的東西。

These genes turn on and off throughout the day to keep your body on a this 24-hour cycle.

這些基因在一天中不斷開關，讓你的身體在這 24 小時的循環中維持運作。

This 7-day time-lapse of the SCN shows these clock genes releasing proteins every 24 hours like clockwork.

這個 SCN 一周七天的縮時攝影顯示，這些時鐘基因 24 小時內都在釋放蛋白質，就像發條一樣。

Researchers who study families of extreme early-risers show that many of them share the same mutation on one of these clock genes, and studies have found similar mutations in hamsters with early chronotypes.

研究極早起家庭的專家指出，許多家庭成員在其中一個時鐘基因上都有相同的轉變，在擁有早起晝夜節律的倉鼠身上也有相似的變化。

But when scientists took out these hamsters' SCN ⏤ their body clock ⏤ and replaced them with the SCN of a normal hamster, they still woke up and went to sleep super early.

但當科學家們取出這些倉鼠的 SCN，也就是他們的生理時鐘，並用正常倉鼠的 SCN 取代後，他們仍然會早睡早起。

And that's because the SCN isn't our only biological clock.

這是因為 SCN 並不是我們唯一的生理時鐘。

You also have all these little clocks in every single cell of your body.

在你體內每個細胞裡，也都有小小的時鐘。

In the early-rising hamsters, these clocks in the body preserved the early chronotype, even after the brain's SCN was taken out.

在這些早起的倉鼠案例中，即使腦中的 SCN 已被取出，他們的身體仍然保留了原本早起的晝夜節律。

And for humans, this helps explain why it's nearly impossible for late sleepers to adjust to society's schedule.

而對人類來說，這幫我們解釋了為什麼晚起床的人很難適應社會的時程。

The cells in their bodies literally won't let them, and that's a problem.

因為他們體內的細胞並不允許他們改變，而這就是問題。

In one study, researchers took healthy people and messed with their sleep schedules.

在一項研究中，研究者找了健康的人，並擾亂他們的睡眠時程。

After three weeks, they had early signs of diabetes.

在三個禮拜後，他們便有了糖尿病的早期症狀。

People with late chronotypes are also more likely to be smokers and to develop depression.

有著較晚晝夜節律的人也更可能成為吸菸者，或罹患憂鬱症。

And maybe that should change the way we think about sleep, you know, it's not this nuisance; it's this, kind of, fundamental part of life.

這或許會改變我們對睡眠的看法，這不是個討厭的東西，而是生命很基本的一部分。

Maybe some late sleepers are lazy, sure, but the rest have been sorely misunderstood.

的確有些晚起床者是懶惰的，但其他人卻是被過度誤解。