Remember that scene in "My Cousin Vinny" where Marisa Tomei says, "My biological clock is ticking likes this" and she starts stomping hard on the floor? When someone says that a woman's biological clock is ticking, it usually means that she actively wants to have a baby and feels time may be short. Scientists debate whether this is a real physiological response from the body as fertility decreases or if it's all in the head. While men can feel a biological clock ticking too, it's generally not with the same urgency, as their time to father a child is much longer than a woman's is to have one. At least, that was conventional wisdom. As both men and women are becoming parents at older ages, scientists have discovered that the father's age may have more to do with a child's genetic health than that of his or her mom. That's just one use of the term "biological clock." Turns out that every living thing – men, women, animals, plants, insects, and algae – all have internal "body clocks" determined by a variety of biological rhythms. These physical, mental and behavioral patterns follow a predictable cycle every day, one that is determined largely by the body's response to light and dark. So why do we have these clocks, and what do they do for us? Here are 10 facts that may surprise you.
大家还记得电影《我的堂兄文尼》中的一个场景吗？玛丽莎·托梅说：“我的生物钟正在滴答作响！”然后她开始在地板上疯狂地跺脚。当有人提到一个女性的生物钟正在滴答作响，那通常意味着她很渴望生一个孩子而且感到时间实在是太紧迫了。科学家们就这一生物钟是否是因生育能力下降而导致的真实生理反应，亦或是纯粹的心理作用而争论不休。不过男人也可以体会到生物钟滴答作响的感觉，但它通常并不像女人的生物钟那样让人倍感紧迫，因为他们当爹的时间比女人生娃的时间长多了。但不管怎样，这都是一种传统的说法。随着年龄的不断增大，男人和女人终会为人父母，科学家们发现，父亲的年龄对孩子基因健康的影响要比母亲大。这仅仅只是“生物钟”的作用之一。结果表明，每一个生物——男人、女人、动物、植物、昆虫、藻类——它们的身体内部都有一个生物钟——由不同的生物节律决定。这些生理、心理和行为模式绝大部分取决于身体对光线强弱做出的不同反应，每天在可预测的周期内循环。所以我们为什么会拥有生物钟？它们能为我们做什么？下面10个事实大概会让你震惊。
10.生物钟很复杂
The body clock isn't some rinky-dink Mickey Mouse watch. In fact, it's a series of clocks controlled by a single "master clock" located in the brain. The system works like this: Genes within the body include instructions for making proteins, which are produced in waves that rise and fall over the course of a day in a type of 24-hour cycle.
生物钟绝对不是一块破旧的普通米老鼠手表。事实上，它是一系列由大脑的“主时钟”控制的时钟。生物钟系统是这样运作的：身体内的基因，包括那些合成蛋白质的指令都是在一天24小时循环的人体波动中形成的。
The master clock manages these circadian rhythms using a group of roughly 20,000 nerve cells called the suprachiasmatic nuclei (SCN), located in the hypothalamus. This section of the brain sits above the optic nerve and produces the hormones that govern body temperature, hunger, sex drive and other workings of the body. The patterns created not only dictate when we eat and sleep, but also control heart rate and the production of blood cells and blood sugar. Although the genes and proteins generally determine individual rhythms, outside factors related to light and dark can also have a significant impact on how your body "tells time".
主时钟调节这些昼夜节律需使用大约20000个位于下丘脑的神经细胞——视交叉上核。下丘脑位于视神经之上,其产生的荷尔蒙能控制体温、摄食、性欲和身体的其他性能。它不仅指示我们何时吃饭睡觉，还控制心率以及生产血细胞和血糖。一般来说，基因和蛋白质决定个人生物节律,但例如光线强弱等的外在因素也可以对你身体的报时产生较大影响。
9.Melatonin Is Our Body's Sleep Aid
9.褪黑素有助于人体睡眠
Among the many hormones pumped through the body, the suprachiasmatic nuclei (SCN) controls the production of the one that makes people want to curl up in a ball on the nearest couch and catch a few zzzs. Melatonin is a naturally occurring chemical that helps regulate the circadian rhythm. The more of it that the body produces, the more likely you are to get sleepy.
在人体内的各种激素里，视交叉上核控制的激素可以让人们想要赶紧找个沙发躺下呼呼大睡。褪黑素是一种天然的化学物质,可以帮助人体调节昼夜节律。身体内产生的褪黑素越多，你就越有可能会昏昏欲睡。
Your melatonin production schedule varies based on light. Remember that the SCN is located just above the optic nerve, which sends information from the eyes to the brain. The less light that comes in – after the sun goes down and the sky becomes dark, for example – the more melatonin the SCN tells the brain to make. Some folks who suffer from sleep disorders will pop melatonin pills to help them get some rest. The effect of these supplements, which are available without a prescription and not regulated in the same way as pharmaceutical drugs, is still not clear. Experts warn that users should be careful to monitor the size and timing of doses so as not to throw off their natural body clocks.
褪黑素利用光来校准生产时间表。记住，视交叉上核只存在视觉神经上方，通过眼睛把信息传递到大脑。举个例子，当太阳下山、天空也暗下来后——进入眼睛的光线变得越来越少，视交叉上核就会提醒大脑生产更多的褪黑素。有些患有睡眠障碍的人会使用褪黑素药物来助眠。但这些无需处方也并不像普通药品一样接受监管的激素到底会对人体产生什么影响还是未知数。专家警告说，药物使用者应仔细监测剂量的大小和服用时间，以免打破人体的自然生物钟。
8.The Body Clock Adapts to Location Changes
8.生物钟会根据位置改变自我调节
Think about the body clock as a human version of the one on your smartphone. If you turn off the phone when you board a plane in New York and turn it back on when your flight lands in Los Angeles, you will notice that the clock automatically adjusts the time to reflect that you're now in a different zone. In the same way, your body clock will eventually adjust to the new light/dark cycle on the West Coast.
把你的生物钟想作是智能手机里的另一个人类版本。假如你在纽约登机时关闭手机，然后在旧金山降落时再打开手机，你会注意到，手机的时间已随时区变化自动调节并且提示你已身处在不同的时区。同样地，你的生物钟最终也会适应西海岸的昼夜。
Anyone who's ever suffered from jet lag knows that the shift doesn't happen right away. Your body has been trained to release melatonin at a certain time each night, and will initially continue to do so even when the optic nerve tells the brain that it's still light outside. Eventually however, and your brain will time the melatonin release to the darkness. In other words, the clock slowly rewinds itself to reflect the rising and falling of the sun and to ensure that you don't spend all of the prime California beach time snoring in your hotel room.
任何曾经有过时差反应的人都知道，生物钟的转变是不会立马发生的，因为只有在晚上的某一特定时间，你的身体才会分泌褪黑素。所以在适应期内，即使视觉神经传递给大脑“现在是白天”的信息，你的身体还是会在原定时间内分泌褪黑素。在生物钟完全适应了新时区的时间后，你的大脑才会在夜间传达“分泌褪黑素”的信息。也就是说，你的生物钟会自我调整，以适应新时区的昼夜，确保你在加州海滩度假时，不至于所有的时间都在酒店房间里呼呼大睡。
7.But It Doesn't Adapt to Daylight Saving Time
7.但生物钟无法适应夏令时
Most American, Canadian and European timepieces spring forward every March, when the powers that be move the official time up an hour so as to allow people to make the most of daylight. Thought to be originally cooked up by Benjamin Franklin, daylight saving time took hold during World War I and became the law of (most) of the land in the U.S. in 1966. Then-President Lyndon Johnson signed legislation requiring official timekeepers to move their clocks forward an hour each spring and back an hour every fall.
美国、加拿大和欧洲的大多数计时器每年从三月起实行夏令时，政府把官方时间提前一小时，以便人们充分享受日光。夏令时由本杰明·富兰克林提出，在一战期间正式执行。1966年，美国绝大部分地区通过立法，确定使用夏令时。当时的总统林登·约翰逊签署了此项法案，要求官方计时员在每年春季开始时调前一小时，每年秋季结束时调后一小时。
The problem is that no one seems to have consulted our body clocks before agreeing to this twice-a-year adjustment. Moving the time ahead an hour does a number on circadian rhythms, particularly in the days immediately after the change when the sun still comes up around the same time. If your alarm goes off at 7 a.m. the day after it springs forward, your body still thinks it's 6 a.m. Because the sun rises later in small increments, it's probably still dark out, and will remain dark for a few months. That means that your body won't shut off the melatonin faucet just yet. One study showed that people's circadian rhythms never fully adjust to daylight saving time and sleep behavior only returns to normal when we go back to regular time.
问题是，在同意一年两次的调整前，并没有人考虑过我们的生物钟能否适应夏令时。把时间提前一小时破坏了昼夜节律，尤其是在更改后几天，太阳依旧在相同的时间升起。在夏令时开始后，如果你的闹钟显示的是7：00am，你的身体依然会默认为是6：00am。因为太阳升起得比较慢，外面可能还是一片黑暗，这种情况可能还会持续几个月。那就意味着在此期间，你的身体并不会停止分泌褪黑素。一项研究发现，人们的生理节律无法完全适应夏令时，而且只有当人们回到正常时间，其睡眠习惯才会回归正常。
6.Birds Do It, Bears Do It
6.万物皆有生物钟
It's like the music group Bloodhound Gang says: "You and me, baby, ain't nothing but mammals." Other mammals also have rhythm-based body clocks that dictate when they rise in the morning and when they lie down for some shut-eye at night. In fact, bears depend on seasonal circadian rhythms to tell them when to hibernate for the winter and when to come out from their hiding places. Birds similarly fly south for the winter based on circadian (or circannual) rhythms that adapt to changes in temperature and the decreasing amount of sunlight per day.
正如血性猎犬帮摇滚乐合唱团唱的那样，“你和我，宝贝，只是哺乳动物而已”。而其他哺乳动物的作息也是依赖于这种有规律的生物钟，早上何时苏醒，晚上又何时入眠。事实上熊也依赖于季节性的昼夜节律，根据时令选择什么时候该去冬眠了，什么时候又该从藏身的地方出来。类似地，鸟类向南方迁徙也是为了适应冬季每日温度下降、光照减少的昼夜节律。
It isn't just mammals who keep time naturally either. Internal rhythms drive plants to open their leaves at dawn and close them at night. They also determine when flowers bloom seasonally.
并不是只有哺乳动物才会有规律的作息时间，植物的内部生物钟会促使它们在黎明的时候舒展开叶子，在傍晚的时候闭合。此外，这种内部生物钟也会决定季节性开花的时间。
审校：围巾、烟囱 编辑：listen 来源：前十网
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