WEBVTT - How Does Jet Lag Work? 0:00:02.040 --> 0:00:07.200 Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff, 0:00:07.200 --> 0:00:09.520 I'm Christian Sega, and today we're going to talk about 0:00:09.640 --> 0:00:12.600 jet lag. I grew up flying back and forth between 0:00:12.640 --> 0:00:15.280 America and Singapore, so I want to share what I 0:00:15.320 --> 0:00:17.960 know about jet lag with you. First of all, jet 0:00:18.040 --> 0:00:20.840 lag occurs when you travel between two or more time 0:00:20.960 --> 0:00:24.000 zones via air travel. And the thing is it disrupts 0:00:24.000 --> 0:00:28.880 your circadian rhythm, your body's natural cycle, and your sleeping patterns. Now, 0:00:28.920 --> 0:00:32.320 the circadian rhythm is dictated by the daily appearance of 0:00:32.360 --> 0:00:36.440 the sun, so light and darkness influence our bodies. But 0:00:36.800 --> 0:00:41.279 when this is disrupted, its official name is d synchronosis. 0:00:41.600 --> 0:00:47.520 Symptoms include insomnia, fatigue, loss of concentration, irritability, depression, and 0:00:47.800 --> 0:00:52.240 even gastro intestinal ills. But look, jet lag or de 0:00:52.479 --> 0:00:58.800 synchronosis is prevalent. A study found that of Americans get it, 0:00:59.080 --> 0:01:03.040 and forty five percent reported that their symptoms were severe. 0:01:03.400 --> 0:01:07.399 So what causes jet lag? Well, there is a whole 0:01:07.560 --> 0:01:11.160 field that exists to study how life is affected by time. 0:01:11.200 --> 0:01:15.520 It's called chronobiology, and here is what it's taught us. First, 0:01:15.959 --> 0:01:19.679 light triggers a reaction in a special eye pigment. This 0:01:19.760 --> 0:01:23.720 activates a response in the neurons of your brains hypothalamus. 0:01:24.000 --> 0:01:26.880 The twenty nerve cells located there. They are called the 0:01:26.959 --> 0:01:31.400 super chismatic nucleus or SCN for short, are what starts 0:01:31.440 --> 0:01:35.559 your body's daily processes and also the lack of light 0:01:35.840 --> 0:01:40.039 causes other developments in your body. Circadian rhythm tells you 0:01:40.120 --> 0:01:42.880 when to sleep and when to wake, and it regulates 0:01:42.920 --> 0:01:48.920 your body temperature, blood pressure, digestion, urine production, and hormone secretion. 0:01:49.080 --> 0:01:52.720 So for example, when it's time to sleep, the SCN 0:01:52.760 --> 0:01:56.520 releases melatonin and that encourages you to go to sleep. 0:01:56.920 --> 0:02:00.000 When you cross into multiple time zones, though, your body 0:02:00.160 --> 0:02:03.480 has trouble resetting quickly, and this is worse when you 0:02:03.560 --> 0:02:08.880 fly east. This is called phase advance. Flying west is 0:02:08.919 --> 0:02:12.720 called phase delay. This is because our circadian clock is 0:02:12.720 --> 0:02:16.600 actually closer to twenty five hours, and going east would 0:02:16.639 --> 0:02:19.960 require going to bed earlier. A study showed it takes 0:02:20.040 --> 0:02:24.160 four days to adjust to a twelve hour phase delay. 0:02:24.240 --> 0:02:27.920 In comparison, it takes more than eight days to adjust 0:02:28.000 --> 0:02:32.000 to a twelve hour phase advance. And also jet lag 0:02:32.400 --> 0:02:34.959 is worse when you have to awaken when your body 0:02:35.080 --> 0:02:38.600 is still at its minimum temperature. There is also research 0:02:38.720 --> 0:02:42.760 from the Salk Institute for Biological Studies that indicates jet 0:02:42.800 --> 0:02:46.320 lag is connected to your l h X one gene 0:02:46.400 --> 0:02:52.560 and this gene regulates neural development in circadian rhythm and sleep. Okay, 0:02:52.600 --> 0:02:55.359 so we've got what causes it. What are the symptoms? 0:02:55.360 --> 0:02:57.320 How do you know if you've got jet lag? Well, 0:02:57.360 --> 0:03:01.200 it's time to talk to Dr Christian. Beyond the insomnia, fatigue, 0:03:01.280 --> 0:03:05.919 loss of concentration, irritability, depression, and even gastro intestinal ills, 0:03:06.200 --> 0:03:10.480 there's even more symptoms. It can aggravate menstrual discomfort or 0:03:10.720 --> 0:03:14.240 contribute to the development of heart disease and diabetes. Jet 0:03:14.320 --> 0:03:18.160 Lag also releases stress hormones, which make you anxious and grumpy. 0:03:18.480 --> 0:03:22.040 It drives up your blood pressure, It sends inflammation stimulating 0:03:22.120 --> 0:03:26.200 chemicals to your arteries. It also disrupts your appetite, regulating hormones. 0:03:26.600 --> 0:03:29.440 It disrupts the release of melotonin, which we mentioned earlier. 0:03:29.680 --> 0:03:32.280 Not only does this affect sleep, but it can also 0:03:32.440 --> 0:03:36.960 protect you from cancer. And finally, research on animals shows 0:03:37.000 --> 0:03:40.240 that there's other symptoms as well. A study at the 0:03:40.320 --> 0:03:43.640 University of California found that when subject to jet lag, 0:03:43.760 --> 0:03:47.960 the brains of hamsters created neurons at half their normal rate. 0:03:48.240 --> 0:03:51.720 They showed memory and learning deficits, and a two thousand 0:03:51.880 --> 0:03:55.120 six study at the University of Virginia found that younger 0:03:55.240 --> 0:03:59.680 mice rebounded from jet lag, but making older mice undergo 0:03:59.760 --> 0:04:03.280 the equivalent of a Washington to Paris flight every week 0:04:03.520 --> 0:04:07.320 would actually increase their death rate. Yeah, that's how big 0:04:07.400 --> 0:04:10.120 it is. Well for mice at least. So we've got 0:04:10.160 --> 0:04:13.960 what causes jet lag and we have its symptoms. You're wondering, 0:04:14.240 --> 0:04:16.880 Dr Christian, where are the remedies? How do I fix this? 0:04:17.360 --> 0:04:19.880 You've probably heard of some of the common remedies, like 0:04:20.040 --> 0:04:22.840 operating on your new time zone before you fly there, 0:04:23.000 --> 0:04:28.160 or wearing yourself out before exercising by exercising. In two 0:04:28.279 --> 0:04:33.919 thousand nine, researchers recommend the following regimen to beat jet lag. First, 0:04:34.240 --> 0:04:37.440 you readjust your rhythm before the trip by using a 0:04:37.600 --> 0:04:42.240 lightbox that simulates daylight. Now, depending on whether you're flying 0:04:42.360 --> 0:04:45.599 phase advance or phase delay, you use the light box 0:04:45.680 --> 0:04:48.560 either in the morning or the evening to stimulate your 0:04:48.600 --> 0:04:52.720 circadian rhythm. Another suggestion from the same researchers was to 0:04:52.880 --> 0:04:56.760 take a melotonin supplement by changing when you take the 0:04:56.839 --> 0:04:59.800 doses in relation to going to sleep, you can alter 0:05:00.040 --> 0:05:04.440 your circadian rhythms. The c d C actually recommends exercise 0:05:04.520 --> 0:05:08.280 to a balanced diet, and lots of rest in the 0:05:08.600 --> 0:05:13.520 weeks before you fly. They also recommend avoiding alcohol and caffeine, 0:05:13.680 --> 0:05:18.000 as well as drinking water. Finally, they recommend wearing loose, 0:05:18.120 --> 0:05:21.159 comfortable clothing while you're flying and moving around the cabin. 0:05:21.600 --> 0:05:26.240 This can help avoid thrombosis or blood clots, so do 0:05:26.440 --> 0:05:29.160 not take sleep medication so you can sleep it off 0:05:29.200 --> 0:05:33.559 in your seat. Immobilization for long periods can actually raise 0:05:33.680 --> 0:05:37.480 your risk for thrombosis. In this can actually lead to 0:05:37.560 --> 0:05:41.599 a stroke. So there you have it. The causes, symptoms, 0:05:41.760 --> 0:05:45.160 and remedies for jet lay. But remember I'm not a 0:05:45.240 --> 0:05:53.840 real doctor. I just play one on podcasts. Check out 0:05:53.839 --> 0:05:55.840 the brain stuff channel on YouTube, and for more on 0:05:55.960 --> 0:05:58.640 this and thousands of other topics, visit how stuff works 0:05:58.760 --> 0:05:59.200 dot com.