Everybody worries. Parents worry about their children, wives worry about husbands. Barack Obama must have worried for months about Hillary Clinton, and all of us are worried about the rapidly rising cost of food and fuel.

But is worry necessary? Traditional wisdom holds that whatever human beings do, it must be for good reason. We may not like worrying, but, so the theory goes, there must be some survival advantage in it.

Is this true? Maybe 10 per cent of what we worry about really matters; the rest is stuff that never happens (the sky is falling!) or already has happened so we can't do anything about it (losing money on the stock market). Studies show that people who worry a lot are generally less effective than those who don't; they get less work done and are often less happy. In experimental tasks, worriers are slower to respond than non-worriers (presumably because worrying burns off mental energy that would be more effectively applied elsewhere), and one recent laboratory study at Yale and Pennsylvania State University has shown that the mere opportunity to worry for five minutes is enough to bring down a person's mood.

Evolutionary products aren't that smart

Broadly speaking, it's a fallacy to presume that all of evolution's products are intelligently designed. Evolution has no foresight - and no hindsight, either. When it stumbles on a solution it tends to stick with it, even if that solution might be less than stellar.

Take, for instance, the human spine. We are stuck with a single-column spine, not because it is ideal but simply because evolution happened to stumble on a mediocre design and, once there, that design became entrenched. From the perspective of an engineer, our spine is clumsy and inelegant; it gets the job done, but hardly in the best way possible. In short, it is what engineers call a kluge. The brain circuits that lead us into worry, stress and anxiety may be similarly clumsy, circuits that are adequate, but with serious vulnerabilities.

At its most useful, worrying is about mobilising us for action. We recognise a threat - perhaps a predator in the distance - and our levels of cortisol, a hormone released in response to stress, rise and we prepare for fight or for flight.

The trouble is that evolution forgot to include an “off” button. Preparing for fight-or-flight makes sense when we're talking about ancestors who needed to decide how to deal with immediate threats such as predators, but not, for the most part, with the sort of persistent situations that drive modern human beings to distraction.

Most worry, at least today, isn't about immediate threat, it's about long-term threat. What will happen if I lose my job? Will my partner ever really love me? Such questions are worth consideration but are not the sort of thing that can be solved in an instant.

In these circumstances, elevated cortisol levels do us no good. The hormone primes our body for physical activity if we, say, have to sprint from danger. However, it also acts to dampen the immune system, which may make us susceptible to infections. What we really need to do is relax and think clearly, but evolution often leads us in the opposite direction; worry often breeds anxiety, paralysis, depression, rather than creative solutions. A recent study from University College London of 542 adults with an average age of 60, found that those who engaged with their problems and sought social support had lower cortisol levels than those who did not.

The word worry comes from a Middle English word “wyrgan”, which means to strangle. And that's what worries often do; they seize us by the throat until we can't think about anything else. When worry takes on a life of its own, it becomes a huge and often pointless drain on our time and energy. Worse, chronic worry may take a toll on our hearts. Earlier this year a study from Cambridge University linked banking crises to an increased number of heart attacks, perhaps because chronic worry and stress can lead people to drink more, smoke, eat too much and take less exercise.

Worry, it has been said, is often like a rocking chair: it gives you something to do, but it doesn't necessarily get you anywhere. Evolution may have given us the opportunity to worry, but that doesn't mean we should take the bait.

How to deal with worries

Worries largely fall into three groups: those that demand immediate attention (“alarm bells”); those that prompt us to focus on continuing problems; and those that anticipate future threats.

Alarm bells are serious business. If you see smoke and are worried about whether there is a fire, by all means drop everything and figure out what needs to be done.

Reminder worries, such as taking the children to their swimming classes or remembering to send Dad a card for Father's Day, should be left to a calendar; use computers or daily planners to offload anxiety.

Future problems deserve due consideration, but don't let them take over your life. Set aside a particular time each day to worry about long-term risks, such as financial difficulties and what you can do about them. Don't let yourself think about those issues at other times.

Prepare, but don't panic It's good to think ahead, but useless to worry about things beyond your control. Don't waste mental energies on problems you can't do anything about.

Become mindful Worry mostly comes from automatic, unmonitored thought. If you find yourself worrying about the same thing twice in a day, ask yourself if you are worrying about something you can change. If not, force yourself to move on. Think about something different.

Making decisions Don't kill yourself trying to make perfect decisions Every decision takes mental energy. It's OK to think long and hard about whether to get married, move to a new city, or to have a child, but when you're deciding between that Saab and a Volvo, don't give yourself more than a few days. Chocolate and vanilla are both nice and, in the final analysis, it won't matter which one you've eaten.

每个人都会焦虑。父母为孩子操心，妻子为丈夫担忧。奥巴马肯定为希拉里。克林顿忧心了数月了，而我们所有人都在为粮油价格快速攀升而焦虑不已。

但一定要焦虑吗？传统名言认为，不管人类要做什么，都应该是为了好的理由。我们可能不喜欢焦虑，不过，正如理论所说，这其中肯定有一定的生存好处。

真的吗？也许我们所忧虑的事情中10%是真有其事；其余的通常就是杞人忧天了！或者是已经发生我们根本不能做什么事情来改变的，比如在股市亏钱了。研究表明无忧无虑的人来说，焦虑过多的人常效率较低，完成工作较少，人通常也不快乐。在实验中，焦虑者比无忧无虑者反应更慢（这可能是因为焦虑本身消耗了精神能量吧，这些能量本来可以用在别处实现更高效率的），而最近来自耶鲁和宾夕法尼亚大学的一项试验研究表明，5分钟的焦虑足够让人情绪低落。

进化的结果并不那么聪明

一般地说，假定所有的进化结果都是聪明地设计的显然是个谬论。进化本身并没有远见，也没有后见知明。当进化停留在一种解决办法上时，通常就会执著于此，哪怕这个解决办法并不是一流的方案。

拿人体的脊椎来举例吧。我们只有一条脊椎，并不是因为这是最理想的，仅仅是因为进化恰恰就停留在这样一个平凡的设计上，一旦存在，这种形式就成为确立无疑的。站在工程师的角度来看，我们的脊椎又笨拙又不优雅。倒是完成了进化，但几乎不是可能的最佳方式。总之，它不过是工程师们称之为的kluge。把我们带入忧心，沮丧，焦虑的脑电流可能（与进化的脊椎一样）同样笨拙，电流是适当的，但存在严重的弱点。

焦虑的最大作用是调动我们立即付诸行动。我们认识到威胁-也许是远处的一个掠夺者，为响应这种压力，释放出荷尔蒙，随之我们的皮质淄醇水平上升，我们就做好了战斗或者是逃跑的准备。

麻烦就是，进化似乎忘记要设计一个取消（关闭键）了。当我们谈到我们的远祖时，所谓的做好准备战斗或逃跑还有点意义，因为他们需要决定怎样应付当前的威胁，就像面对掠夺者时；不过，对大部分情况来说，一直以来持续的情况是，现代人类被驱往娱乐上，这时候就没有什么意义了。

至少今天来说，焦虑并不是关于紧迫的威胁的，而是关于长期威胁的。比如老是想着：如果我失业了怎么办呢？我的配偶真正爱我吗？这样的问题值得考虑，但并不是可以立即解决的事情。

在这些情况下，皮质醇水平上升对我们没有好处。加入说，我们得赶快脱离危险，荷尔蒙可以帮助我们的身体立即做好行动的准备。不过，它也会促使我们消除我们的防御系统，这会让我们容易受感染。其实我们真正需要做的是放松下来考虑清楚，而进化结果却常常把我们带往相反的方向。担心通常带来焦虑，接着是麻木，然后是消沉，而不是富有创意的解决办法。伦敦大学对平均年龄在60岁左右的542位成年人所作的一项最新研究发现，致力于寻求社会支援来解决自身问题的人比那些不寻求支援的人的皮质醇水平较低。

“焦虑(Worry)”这个词来源于中古英语单词“wyrgan”,意思是扼死。这正是焦虑的通常结果。焦虑扼住我们的喉咙，最后我们不能想到其他任何事情。当焦虑占据了生活的全部时,就变成一个巨大而没有意义的消耗，无端的消耗我们的时间与精力。更糟糕的是，持久地焦虑会给我们的心脏造成损伤。年初剑桥大学的研究发现银行危机带来更多的心脏病，也许是因为长久的焦虑和抑郁可导致人们酗酒，吸烟，暴食，更少锻炼。

据说，焦虑就像一把摇摆不停的椅子，它让你总是有事可做，但又让你碌碌无为。也许进化给了我们焦虑的机会，但并不意味着我们应该背上这份折磨吧。

怎样应付焦虑症

焦虑大部分可以分成三类：需要立即注意的（警钟类），一类是促使我们关注在持续的问题上，还有一类是预期未来的威胁。

警钟类焦虑：最严重的一类。如果你看到冒烟就担心会不会是起火了，那么放下所有的事情，赶快断定要怎么做。

提醒类焦虑：类似送孩子去上游泳课或要记住给父亲送父亲节卡片这样的事情，可以在日历上注明，用计算计或者日常计划可以解除这类焦虑。

对未来问题的焦虑：值得正当（程度）的考虑，但不能让其控制了自己的生活。每天留出一个特定的时间来考虑长期的风险，比如财务困境，想想对此有什么办法。不让自己在其他时间考虑这些问题。

预先准备，但不要恐慌：能事先想到当然很好，但为自己控制能力之外的事情去担心就没有必要了。不要再自己能力范围之外的问题上浪费精力。

怎样应付焦虑症

焦虑大部分可以分成三类：需要立即注意的（警钟类），一类是促使我们关注在持续的问题上，还有一类是预期未来的威胁。

警钟类焦虑：最严重的一类。如果你看到冒烟就担心会不会是起火了，那么放下所有的事情，赶快断定要怎么做。

提醒类焦虑：类似送孩子去上游泳课或要记住给父亲送父亲节卡片这样的事情，可以在日历上注明，用计算计或者日常计划可以解除这类焦虑。

对未来问题的焦虑：值得正当（程度）的考虑，但不能让其控制了自己的生活。每天留出一个特定的时间来考虑长期的风险，比如财务困境，想想对此有什么办法。不让自己在其他时间考虑这些问题。

预先准备，但不要恐慌：能事先想到当然很好，但为自己控制能力之外的事情去担心就没有必要了。不要再自己能力范围之外的问题上浪费精力。

时刻留心：焦虑更多来自没有监视的自动的想法。如果你发现自己为同一件事一天考虑两遍，问问自己你担心的事你能改变吗?如果答案是不能，那么就迫使自己不要想了。考虑一下其他事情好了。

做出决定：不要让自己精疲力竭地来作出完美的决定。每一个决定都耗费精力的。对是否结婚或搬去另一个城市或者是要孩子这样的问题考虑成熟些谨慎些是好的。但在决定是买萨博还是沃尔沃车这样的问题上，给自己的考虑时间不要超过几天。巧克力还是香草布丁都不错，在最后的分析对比中，到底你吃的是什么并不那么重要。