Jet Lag: Prevention and Cure

　　The problem of Jet Lag is one every international traveller comes across at some time. But do you have to suffer? Understand what it is, and how a careful diet can minimize its worst effects, and your flights will be less stressful.

　　The effects of rapid travel on the body are actually far more disturbing than we realize. Jet Lag is not a psychological consequence of having to readjust to a different time zone. It is due to changes in the body's physiological regulatory mechanisms, specifically the hormonal systems, in a different environment.

　　Confused? So was John Foster Dulles, the American Secretary of State, when he flew to Egypt to conduct negotiations on the Aswan Dam.

　　He later blamed his poor judgement on Jet Lag.

　　The effects can be used to advantage, too. President Johnson once conducted an important meeting in Guam and kept the entire proceedings at Washington DC time. The White House working personnel were as fresh as paint, while the locals, in this case, were jet-lagged.

　　Essentially, they had been instantaneously transported to America.

　　Now that we understand what Jet Lag is, we can go some way to overcoming it. A great number of the body's events are scheduled to occur at a certain time of day. Naturally these have to be regulated, and there are two regulatory systems which interact.

　　One timing system comes from the evidence of our senses and stomachs, and the periodicity we experience when living in a particular time zone. The other belongs in our internal clocks (the major one of which may be physically located in a part of the brain called the suprachiasmatic nucleus) which, left alone, would tie the body to a 25 hour - yes, 25 - rhythm. Normally the two timers are in step, and the external cues tend to regularise the internal clocks to the more convenient 24 hour period.

　　If, however, you move the whole body to a time zone which is four hours different, the two clocks will be out of step, like two alarm clocks which are normally set together, but which have been reset a few hours apart. Whereas the two clocks would normally sound their alarms together, now they ring at different times. Similarly, the body can be set for evening while the sun is rising.

　　In time the physiological system will reset itself, but it does take time. One easily monitored rhythm is palm sweating. A man flown to a time zone different by 10 hours will take eight days to readjust his palm sweat. Blood pressure, which is also rhythmical, takes four days to readjust.

　　One reason for this discrepancy is that different bodily events are controlled by different factors. The hormone cortisol, which controls salt and water excretion, is made in the morning, wherever the body is. But the growth hormone is released during sleep, whenever in the day that sleep occurs. Normally these two hormones are separated by seven or eight hours, but if the body arrives at a destination in the early morning (local) and goes to sleep as soon as possible, the two hormones will be released simultaneously.

　　What can we do about it? It is not feasible to wait four days until the body is used to the new time zone. Fortunately there is a short cut. It relies on two things - the power of the stomach to regulate the timing of other events, and the pharmacological actions of coffee.

　　The basic assumptions are:

　　Coffee delays the body clock in the morning, and advances it at night. Coffee at mid-afternoon is neutral.

　　Protein in meals stimulates wakefulness, while carbohydrates promote sleep.

　　Putting food into an empty stomach helps synchronize the body clock.

　　时差综合症的防备和医治

　　高速飞翔时因时差而引起的生理节奏的琢磨是每一个跨国游览者有时会遇到的问题。但你有必要得忍耐吗？假如你了解它是怎么回事，而且知道怎么留意饮食才干够将其最坏影响减到最小程度，你的飞翔就不会那么紧张了。

　　快速游览对身体的影响实际上比咱们所意识到的愈加令人不安。调整的习行因时差而引起的生理节奏的损坏不是有必要从头调整去合适不一起区的心思影响。它是由人体内的生理调理结构，特别是荷尔蒙体系在不同环境的改变引起的。感到困惑了吗？美国国务卿约翰福斯特杜勒斯飞往埃及进行关于阿斯旺大坝的商洽时也是这样。后来，他把他的不抱负的判别归咎于时差反响的不良影响。

　　时差的影响也能够加以使用。约翰逊总统曾经在关岛举行重要会议，其一切活动都按华盛顿时刻进行。白宫工作人员个个精神焕发，而在这种状况下，当地人却受时差反响之苦。实际上，如同他们刚刚被飞机送到美国相同。

　　已然咱们懂得了什么是高速飞翔时差综合症。很天然，这些活动不得不加以调理，人表现人有两套相互影响的调理体系。

　　一个守时体系表现在咱们的感觉和胃以及居住在一个特守时区时，咱们所阅历的周期。另一个守时体系在咱们的人体时钟内，这些人体时钟在不受搅扰时，会使人体有一个25小时，是的25小时的生理节奏。一般状况下，这两种守时器是步调一致的。外部信号常常调理人体时钟命使之抵达更为便当的24小时周期。

　　但是，假如你将整个身体转移到相差四个小时的时区，这两个小时钟就不协调了。就像两个闹钟一般一同设置，但被从头设置时相差了好几个小时。尽管这两个时钟一般会一同闹时，但现在它们在不一起刻响起。相似的，当太阳升起时身体或许被设定为晚上。

　　通过一段时刻今后，生理体系将会从头调整过来。但这确实需求时刻。一个简单监测的节律是手掌出汗的节律。血压也是有节律的，需求四天时刻才干得到从头调整。

　　构成这种差异的百不同的身体活动由不同要素的分配。不管身在何处，控制盐和水分分泌的皮质醇激素是早上发生的。但不管何时睡觉，生长激素是在睡觉中开释的。一般这两种激素相隔七、八个小时开释，但假如人体在一大早抵达意图地，而且赶快入眠，这两种激素将一起开释。

　　关于这点咱们能做些什么呢？等候几天直到身体习惯新的时区是不可取的。幸亏，有一条捷径。它依托两点――胃调理其他活动守时的才能和咖啡的药物效果。

　　根本的道理是：

　　咖啡在早上能够推迟人体时钟，在晚间能够提前人体时钟。咖啡在下午三点左右是中性的。食物中的蛋白质使人不眠，而碳水化合物却使人易于入眠。空腹吃食物协助人体时钟按时。

更多备考材料：www.letou-app.net/bkzl/