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Speaker 1: Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff,

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Speaker 1: I'm Christian Sega, and today we're going to talk about

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Speaker 1: jet lag. I grew up flying back and forth between

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Speaker 1: America and Singapore, so I want to share what I

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Speaker 1: know about jet lag with you. First of all, jet

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Speaker 1: lag occurs when you travel between two or more time

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Speaker 1: zones via air travel. And the thing is it disrupts

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Speaker 1: your circadian rhythm, your body's natural cycle, and your sleeping patterns. Now,

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Speaker 1: the circadian rhythm is dictated by the daily appearance of

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Speaker 1: the sun, so light and darkness influence our bodies. But

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Speaker 1: when this is disrupted, its official name is d synchronosis.

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Speaker 1: Symptoms include insomnia, fatigue, loss of concentration, irritability, depression, and

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Speaker 1: even gastro intestinal ills. But look, jet lag or de

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Speaker 1: synchronosis is prevalent. A study found that of Americans get it,

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Speaker 1: and forty five percent reported that their symptoms were severe.

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Speaker 1: So what causes jet lag? Well, there is a whole

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Speaker 1: field that exists to study how life is affected by time.

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Speaker 1: It's called chronobiology, and here is what it's taught us. First,

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Speaker 1: light triggers a reaction in a special eye pigment. This

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Speaker 1: activates a response in the neurons of your brains hypothalamus.

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Speaker 1: The twenty nerve cells located there. They are called the

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Speaker 1: super chismatic nucleus or SCN for short, are what starts

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Speaker 1: your body's daily processes and also the lack of light

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Speaker 1: causes other developments in your body. Circadian rhythm tells you

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Speaker 1: when to sleep and when to wake, and it regulates

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Speaker 1: your body temperature, blood pressure, digestion, urine production, and hormone secretion.

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Speaker 1: So for example, when it's time to sleep, the SCN

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Speaker 1: releases melatonin and that encourages you to go to sleep.

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Speaker 1: When you cross into multiple time zones, though, your body

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Speaker 1: has trouble resetting quickly, and this is worse when you

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Speaker 1: fly east. This is called phase advance. Flying west is

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Speaker 1: called phase delay. This is because our circadian clock is

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Speaker 1: actually closer to twenty five hours, and going east would

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Speaker 1: require going to bed earlier. A study showed it takes

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Speaker 1: four days to adjust to a twelve hour phase delay.

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Speaker 1: In comparison, it takes more than eight days to adjust

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Speaker 1: to a twelve hour phase advance. And also jet lag

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Speaker 1: is worse when you have to awaken when your body

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Speaker 1: is still at its minimum temperature. There is also research

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Speaker 1: from the Salk Institute for Biological Studies that indicates jet

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Speaker 1: lag is connected to your l h X one gene

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Speaker 1: and this gene regulates neural development in circadian rhythm and sleep. Okay,

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Speaker 1: so we've got what causes it. What are the symptoms?

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Speaker 1: How do you know if you've got jet lag? Well,

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Speaker 1: it's time to talk to Dr Christian. Beyond the insomnia, fatigue,

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Speaker 1: loss of concentration, irritability, depression, and even gastro intestinal ills,

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Speaker 1: there's even more symptoms. It can aggravate menstrual discomfort or

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Speaker 1: contribute to the development of heart disease and diabetes. Jet

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Speaker 1: Lag also releases stress hormones, which make you anxious and grumpy.

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Speaker 1: It drives up your blood pressure, It sends inflammation stimulating

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Speaker 1: chemicals to your arteries. It also disrupts your appetite, regulating hormones.

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Speaker 1: It disrupts the release of melotonin, which we mentioned earlier.

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Speaker 1: Not only does this affect sleep, but it can also

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Speaker 1: protect you from cancer. And finally, research on animals shows

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Speaker 1: that there's other symptoms as well. A study at the

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Speaker 1: University of California found that when subject to jet lag,

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Speaker 1: the brains of hamsters created neurons at half their normal rate.

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Speaker 1: They showed memory and learning deficits, and a two thousand

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Speaker 1: six study at the University of Virginia found that younger

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Speaker 1: mice rebounded from jet lag, but making older mice undergo

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Speaker 1: the equivalent of a Washington to Paris flight every week

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Speaker 1: would actually increase their death rate. Yeah, that's how big

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Speaker 1: it is. Well for mice at least. So we've got

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Speaker 1: what causes jet lag and we have its symptoms. You're wondering,

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Speaker 1: Dr Christian, where are the remedies? How do I fix this?

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Speaker 1: You've probably heard of some of the common remedies, like

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Speaker 1: operating on your new time zone before you fly there,

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Speaker 1: or wearing yourself out before exercising by exercising. In two

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Speaker 1: thousand nine, researchers recommend the following regimen to beat jet lag. First,

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Speaker 1: you readjust your rhythm before the trip by using a

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Speaker 1: lightbox that simulates daylight. Now, depending on whether you're flying

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Speaker 1: phase advance or phase delay, you use the light box

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Speaker 1: either in the morning or the evening to stimulate your

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Speaker 1: circadian rhythm. Another suggestion from the same researchers was to

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Speaker 1: take a melotonin supplement by changing when you take the

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Speaker 1: doses in relation to going to sleep, you can alter

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Speaker 1: your circadian rhythms. The c d C actually recommends exercise

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Speaker 1: to a balanced diet, and lots of rest in the

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Speaker 1: weeks before you fly. They also recommend avoiding alcohol and caffeine,

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Speaker 1: as well as drinking water. Finally, they recommend wearing loose,

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Speaker 1: comfortable clothing while you're flying and moving around the cabin.

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Speaker 1: This can help avoid thrombosis or blood clots, so do

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Speaker 1: not take sleep medication so you can sleep it off

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Speaker 1: in your seat. Immobilization for long periods can actually raise

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Speaker 1: your risk for thrombosis. In this can actually lead to

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Speaker 1: a stroke. So there you have it. The causes, symptoms,

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Speaker 1: and remedies for jet lay. But remember I'm not a

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Speaker 1: real doctor. I just play one on podcasts. Check out

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Speaker 1: the brain stuff channel on YouTube, and for more on

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Speaker 1: this and thousands of other topics, visit how stuff works

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Speaker 1: dot com.