Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff, I'm Christian Sega, and today we're going to talk about jet lag. I grew up flying back and forth between America and Singapore, so I want to share what I know about jet lag with you. First of all, jet lag occurs when you travel between two or more time zones via air travel. And the thing is it disrupts
your circadian rhythm, your body's natural cycle, and your sleeping patterns. Now, the circadian rhythm is dictated by the daily appearance of the sun, so light and darkness influence our bodies. But when this is disrupted, its official name is d synchronosis. Symptoms include insomnia, fatigue, loss of concentration, irritability, depression, and even gastro intestinal ills. But look, jet lag or de
synchronosis is prevalent. A study found that of Americans get it, and forty five percent reported that their symptoms were severe. So what causes jet lag? Well, there is a whole field that exists to study how life is affected by time. It's called chronobiology, and here is what it's taught us. First, light triggers a reaction in a special eye pigment. This activates a response in the neurons of your brains hypothalamus.
The twenty nerve cells located there. They are called the super chismatic nucleus or SCN for short, are what starts your body's daily processes and also the lack of light causes other developments in your body. Circadian rhythm tells you when to sleep and when to wake, and it regulates your body temperature, blood pressure, digestion, urine production, and hormone secretion. So for example, when it's time to sleep, the SCN releases melatonin and that encourages you to go to sleep.
When you cross into multiple time zones, though, your body has trouble resetting quickly, and this is worse when you fly east. This is called phase advance. Flying west is called phase delay. This is because our circadian clock is actually closer to twenty five hours, and going east would require going to bed earlier. A study showed it takes four days to adjust to a twelve hour phase delay. In comparison, it takes more than eight days to adjust
to a twelve hour phase advance. And also jet lag is worse when you have to awaken when your body is still at its minimum temperature. There is also research from the Salk Institute for Biological Studies that indicates jet lag is connected to your l h X one gene and this gene regulates neural development in circadian rhythm and sleep. Okay, so we've got what causes it. What are the symptoms? How do you know if you've got jet lag? Well,
it's time to talk to Dr Christian. Beyond the insomnia, fatigue, loss of concentration, irritability, depression, and even gastro intestinal ills, there's even more symptoms. It can aggravate menstrual discomfort or contribute to the development of heart disease and diabetes. Jet Lag also releases stress hormones, which make you anxious and grumpy. It drives up your blood pressure, It sends inflammation stimulating chemicals to your arteries. It also disrupts your appetite, regulating hormones.
It disrupts the release of melotonin, which we mentioned earlier. Not only does this affect sleep, but it can also protect you from cancer. And finally, research on animals shows that there's other symptoms as well. A study at the University of California found that when subject to jet lag, the brains of hamsters created neurons at half their normal rate.
They showed memory and learning deficits, and a two thousand six study at the University of Virginia found that younger mice rebounded from jet lag, but making older mice undergo the equivalent of a Washington to Paris flight every week would actually increase their death rate. Yeah, that's how big it is. Well for mice at least. So we've got what causes jet lag and we have its symptoms. You're wondering, Dr Christian, where are the remedies? How do I fix this?
You've probably heard of some of the common remedies, like operating on your new time zone before you fly there, or wearing yourself out before exercising by exercising. In two thousand nine, researchers recommend the following regimen to beat jet lag. First, you readjust your rhythm before the trip by using a lightbox that simulates daylight. Now, depending on whether you're flying phase advance or phase delay, you use the light box either in the morning or the evening to stimulate your
circadian rhythm. Another suggestion from the same researchers was to take a melotonin supplement by changing when you take the doses in relation to going to sleep, you can alter your circadian rhythms. The c d C actually recommends exercise to a balanced diet, and lots of rest in the weeks before you fly. They also recommend avoiding alcohol and caffeine, as well as drinking water. Finally, they recommend wearing loose, comfortable clothing while you're flying and moving around the cabin.
This can help avoid thrombosis or blood clots, so do not take sleep medication so you can sleep it off in your seat. Immobilization for long periods can actually raise your risk for thrombosis. In this can actually lead to a stroke. So there you have it. The causes, symptoms, and remedies for jet lay. But remember I'm not a real doctor. I just play one on podcasts. Check out the brain stuff channel on YouTube, and for more on this and thousands of other topics, visit how stuff works dot com.