(单词翻译:单击)
There are lots of good reasons to exercise,
锻炼有很多好理由，
like toning those biceps, the satisfaction of breaking a sweat,
比如它能锻炼肱二头肌，能让你有大汗淋漓的满足感，
or just actually using that gym membership you got when you made that resolution.
或者它只是利用你在下决心时办得健身会员资格。
And exercising is good for your general health and wellness.
锻炼对你的身心健康都有好处。
It can also make you happier.
它能让你更快乐。
That's because working out doesn't just affect your body-fat percentage,
这是因为锻炼不仅影响你的身体脂肪比例，
it can also change the way you feel by boosting happy brain chemicals and buffering your response to stress.
它还可以通过增加快乐的大脑化学物质、缓冲你对压力的反应来改变你的感觉。
And the effects can be so dramatic
它的影响可以如此巨大，
that many psychologists think regular exercise can help treat disorders like anxiety and depression.
以至于许多心理学家认为定期锻炼可以帮助治疗焦虑症和抑郁症等障碍。
Lots of research studies over the past decades have drawn a clear link between exercise and positive feelings.
过去几十年的大量研究表明，锻炼和积极情绪之间有着明显的联系。
And the mood-boosting effects of a single bout of exercise can stick around for up to 24 hours, according to some studies.
一些研究表明，一场运动的情绪刺激效果可以持续24个小时，
Part of why you feel so good after exercise, counterintuitive as it might seem, is because exercise is stressful.
你在锻炼后感觉良好，这种好似乎违反直觉，部分原因是锻炼让人有压力。
Technically speaking, exercise is a physical stress on the body,
从技术上讲，锻炼是对身体的一种生理压力，
which means it activates the hypothalamic-pituitary-adrenal or HPA axis,
这意味着它能激活下丘脑-垂体-肾上腺轴（HPA轴），
the part of your nervous system that controls your body's stress response.
后者是你神经系统的一部分，控制着你身体的压力反应。
One of the things it does is signal production of the stress hormone cortisol.
它的功能之一就是产生压力荷尔蒙皮质醇信号。
Cortisol helps produce the physical changes you associate with stress or exercise, like elevated heart rate.
皮质醇有助于产生与压力或运动相关的身体变化，比如心率加快。
But it also contributes to a negative feedback loop that eventually shuts down the HPA axis.
但它也会产生一个负反馈环路，最终关闭HPA轴。
Levels of cortisol in your blood rise initially when you're stressed,
当你感到有压力的时候，血液中的皮质醇水平最初会升高，
but once they reach a certain level, they signal the HPA axis to relax.
但是它们一旦达到一定水平后就会向HPA轴发出休息的信号。
And it takes your body some time to reset everything before cortisol levels can rise again after that happens.
皮质醇水平再次升高之前，你的身体需要一段时间来重置所有的东西。
That means exercise can act as a buffer to other stresses that come shortly after,
这意味着锻炼可以缓冲不久之后到来的其他压力，
even if they're psychological rather than physical.
即使压力是心理上的，而不是身体上的。
For example, a 2015 study in the journal Psychoneuroendocrinology
例如，2015年发表在《心理神经内分泌学》杂志上的一项研究
had 40 young men do what's called the Montreal Imaging Stress Task.
找了40位年轻男性来做蒙特利尔成像应激任务（Montreal Imaging Stress Task）。
Basically, you do math problems while a ticker shows your expected performance on a big screen,
它的基本内容是，你在做数学题时，指示器会在一个大屏幕上显示你的期望性能，
which is not exactly relaxing.
这并不是真正的放松。
The researchers found that when subjects ran on a treadmill for half an hour beforehand,
研究人员发现，当受试者提前半小时在跑步机上跑步时，
they had lower cortisol levels during the test.
他们在测试期间的皮质醇水平较低。
But the happy feelings associated with exercise don't just come from handling other stresses better.
但与锻炼相关的快乐情绪并不仅仅来自于你能更好地处理其他压力。
Working out increases your levels of endocannabinoids,
锻炼可以提高你的内源性大麻素水平，
the neurotransmitters linked to the so-called 'runner's high'.
内源性大麻素是与所谓的“跑步者愉悦感”有关的神经递质。
They decrease anxiety by binding to cannabinoid receptors in the brain,
它们通过与大脑中的大麻素受体结合来减少焦虑，
yes, cannabinoid like cannabis because they're same receptors,
是的，大麻素喜欢大麻，因为它们是相同的受体，
the psychoactive compounds in marijuana interact with.
大麻中的精神活性化合物会相互作用。
Endocannabinoids also help rein in an overactive HPA axis,
内源性大麻素也有助于抑制过度活跃的HPA轴，
so that's another way exercise can make you more resilient to other types of stress.
这是锻炼让你在其他类型的压力中更容易复原的另一种方式。
Working out also ups your levels of serotonin,
锻炼也能提高你的血清素水平，
a neurotransmitter involved in the regulation of mood and emotion.
后者是调节情绪的神经递质。
The harder you work, the more serotonin you produce.
你工作越努力，产生的血清素就越多。
That's especially interesting, because low serotonin is linked to disorders like depression and anxiety.
这非常有趣，因为低血清素与抑郁和焦虑等疾病有关。
In fact, many antidepressant medications work by directly or indirectly increasing levels of serotonin in your brain.
事实上，许多抗抑郁药物的作用就是直接或间接增加你大脑中的血清素水平。
And another chemical, called brain-derived neurotrophic factor, or BDNF, also goes up during exercise.
另一种叫做脑源性神经营养因子(BDNF)的化学物质也在运动过程中增加。
BDNF is like fertilizer for your brain.
BDNF就像是你的大脑肥料。
It helps neurons grow and form connections with other neurons, and generally improves brain health.
它能帮助神经元生长并与其他神经元形成连接，通常能改善大脑健康。
Researches haven't yet figured the exact link between BDNF and mood,
研究还没有发现BDNF和情绪之间的确切联系，
but it might help by enhancing your neuroplasticity,
但它可能有助于增强你的神经可塑性，
the flexibility that allows your brain to reorganize when you learn or experience something.
即你在学习或经历某事时，大脑可以整顿的灵活性。
In depression, neuroplasticity is disrupted,
抑郁症患者的神经可塑性被破坏，
which makes it difficult for the brain to compensate if important neural circuits become impaired.
这使得大脑很难在重要的神经回路受损时进行弥补。
So elevating BDNF might help reverse or prevent that.
因此，提升BDNF水平可能有助于扭转或防止此类情况。
And, maybe unsurprisingly, antidepressants also tend to increase BDNF levels.
也许不出意料，抗抑郁药也会增加BDNF的水平。
All that said, the similarities between exercise and antidepressants don't mean they're the same.
尽管如此，运动和抗抑郁药的相似之处并不意味着它们是相同的。
The studies that look at the effects of exercise on a molecular level
着眼于运动在分子水平上的影响的研究
are usually only measuring things in the short-term, like, right after you hop off the treadmill.
通常只测量短期内，比如你跳下跑步机后的指标。
Which doesn't tell you much about how long the boost lasts.
这并不能告诉你很多刺激持续多久的信息。
But the research is increasingly showing the long-term benefits of regular exercise, too.
但研究也逐渐显示出定期锻炼的长期益处。
One study, published in 2017,
发表在2017年的一项研究
examined the mental health and exercise habits of almost 34,000 Norwegians for more than a decade.
对近3.4万名挪威人的心理健康和锻炼习惯进行了十多年的调查。
And the researchers found that people who didn't exercise
研究人员发现那些不锻炼的人
had a 44% greater chance of developing depression compared to those who exercised 1-2 hours a week.
与那些每周锻炼1到2个小时的人相比，患抑郁症的几率要高44%。
Other research has found that, at least for mild to moderate depression,
其他研究已发现，至少对患轻度和中度抑郁的人来说，
exercise can be just as beneficial as other treatment options.
锻炼可以和其他治疗方案一样有益。
For example, a 2011 study in the journal Psychosomatic Medicine of over 200 adults diagnosed with depression
例如，2011年《身心医学》(Psychosomatic Medicine)杂志发表了一项对超过200名患有抑郁症的成年人的研究，
found that exercise was just as effective as an antidepressant over a four month period.
结果发现，在四个月的周期里，运动和抗抑郁药一样有效。
Now, before you go out and swap your Paxil for pilates,
现在，在你出去把帕罗西汀换成普拉提课程之前，
it's worth noting that there were some biases in this study.
要注意这项研究存在一些偏见。
For one thing, the subjects were people who responded to an ad about research on treating depression with exercise,
首先，受试者是对运动能治疗抑郁症研究的广告有反应的人
so a lot of them were very pro-exercise in the first place.
所以很多人一开始就很赞成运动。
The researchers also noticed that some people seemed anti-medication as a treatment.
研究人员还注意到，一些人似乎把抗药物作为一种治疗了。
All of which would have affected the results.
这些因素都会影响结果。
But no matter how exercise compares to other treatment options,
但无论运动与其他治疗方案相比如何，
research has made it pretty clear that working out has all kinds of benefits for both your mind and body.
研究都已明确，锻炼对你的身心有各种好处。
So if you think you might be depressed, definitely see a doctor.
所以，如果你认为自己可能会抑郁，一定要去看医生。
But if you're stressed about a project, or just feeling down in the dumps,
但是如果你对一个项目感到压力，或者只是心情沮丧，
getting a little bit of exercise might help.
做一点儿运动可能会有帮助。
Thanks for watching this episode of SciShow Psych!
感谢您收看本期的心理科学秀！
If you want to learn more about that buzz you get from working out,
如果你想了解更多锻炼中的忙碌，
you can learn more about that in our episode on why you get that runner's high.
可以在我们关于“为什么你会得到跑步者愉悦感”的节目中了解到更多内容。
