Jet Lag: What It Is and How to Beat It - Medical News Today Jet Lag: What It Is and How to Beat It Written by Christian NordqvistReviewed by University of Illinois-Chicago, School of Medicine 4 2 Jet lag, also known as time zone change syndrome or desynchronosis, occurs when people travel rapidly from east to west, or west to east in an aircraft. Jet lag is a physiological condition that upsets our body's circadian (daily) rhythms, it is therefore classified as a circadian rhythm disorder. Jet lag symptoms tend to be more severe when the person travels from westward compared to eastward. Contents of this article: Treatments and prevention Fast facts on jet lag Here are some key points about jet lag. More detail and supporting information is in the main article. Symptoms of jet lag can include headaches , insomnia , and irritability Circadian rhythms are generated in a part of the brain called the suprachiasmatic nucleus When circadian rhythms are significantly upset, it is called jet lag Traveling from west to east tends to make jet lag worse What are circadian rhythms? Our circadian rhythms regulate our sleep-wake cycle.

Circadian rhythms are 24-hour cycles in the biochemical, physiological, and behavioral processes of our bodies. They are often referred to as our body clock. Our circadian rhythms are driven by an internal time-keeping system. This biological clock is set (entrained) by external environmental factors, such as the light-dark cycle of night and day. Put simply, our circadian rhythm regulates our daily activities, such as sleep, waking, eating, and body temperature regulation. When our internal biological clock needs to be reset, it causes jet lag; other than long flights east or west, this type of resetting can cause problems in shift workers, and in some sleeping disorders. What is jet lag? People with jet lag have their sleep-wake patterns disturbed. They may feel drowsy, tired, irritable, lethargic, and slightly disoriented. The more time zones that are crossed rapidly, the more severe jet lag symptoms are likely to be. Researchers from the University of Washington revealed that the disruption occurs in two separate but linked groups of neurons in a structure called the suprachiasmatic nucleus (SCN); the SCN sits below the hypothalamus at the base of the brain.

One group is synchronized with deep sleep and the effects of physical fatigue and the other controls the dream state of rapid eye movement ( REM ) sleep. The group of neurons involved in REM sleep finds it harder to adjust to the new cycle and the two groups become out of sync. The older a person is, the more severe their jet lag symptoms generally are and the longer they will take to get their body clocks back into sync. A child's symptoms will usually be much milder, and they will recover faster. Causes of jet lag If we travel across a number of time zones and experience daylight and darkness cycles different from the rhythms we are used to, our body clock will be out of sync (synchronization). Our natural circadian rhythm, our sleep-wake pattern, will be upset, as will our rhythms for eating and working. Our hormone regulation may be out of sync with what is going on around us; also, our body temperature, which has a daily cycle, might be out of sync. Until all of these factors can respond properly to our new environment, we are jet-lagged. Traveling through time zones, and also from the northern hemisphere to the southern hemisphere at the same time can cause additional problems.

Not only does the body have to get used to a new time zone, but the seasons are different. For instance, if you suffer from hay fever and leave the northern hemisphere in fall and land about 400 miles south of Buenos Aires, Argentina, your dormant hay fever may return. Your body will have to cope with a change in daily occurrences as well as seasonal phenomena. However, for jet lag to occur, there has to be an east-west or west-east movement. Flying from Chicago to Santiago, Chile will not cause jet lag because it is directly south, no time zones are crossed. But, even a flight from the eastern coast of the United States to its western coast can cause jet lag. Jet lag does not usually occur if the individual crossed just one or two time zones. Experts say that there is a link between environmental levels of oxygen and susceptibility to jet lag. An airplane's cabin air pressure is much lower than it is at sea level, meaning that the amount of oxygen reaching the brain may be reduced when people are flying. This can make us slightly lethargic, resulting in a higher risk of more severe jet lag symptoms. Which direction of travel is worse for jet lag? Jet lag is normally more severe when traveling eastwards.

Which is worse, east-west or west-east? - If you travel eastward , the chances of more severe symptoms are greater, because the day will seem longer. If you land in London from Chicago at 10 p.m. London time, it is still 4 p.m. Chicago time. Come midnight, it will be hard to sleep because your body clock it is still saying it is 6 p.m. (not bedtime). However, if you land in Chicago from London, by 10 p.m. you will find it easier to get to sleep, because 10 p.m. in Chicago is 4 a.m. in London - if you live in London it is very late to be awake. A good night's sleep helps recover from jet lag more quickly. Experts say that drinking alcohol during (or before) the flight may result in more severe jet lag. Symptoms of jet lag Symptoms of jet lag vary and depend on several factors, including how many time zones were traveled, the individual's age, state of health, whether or not alcohol was consumed during the flight, how much was eaten during the flight, and how much sleep there was during the flight.

The following are typical jet lag symptoms: Headaches Attention deficit - hard to concentrate on one thing for long Loss of appetite Dizzy unsettled feeling - this may be due to the constant movements of the aircraft Some gastrointestinal disturbances, such as diarrhea or constipation Jet lag treatments and prevention There are a number of things to do to minimize the symptoms of jet lag. Physical fitness and health - studies have found that people who are physically fit, rest properly, and eat a well-balanced diet tend to have fewer and lighter symptoms than other individuals. Control underlying medical conditions - if there is an existing medical condition, such as a lung disease, heart disease , or diabetes , following the treatment plan can help minimize the impact of jet lag. Dehydration - drinking plenty of liquids during the flight - preferably water and definitely not alcohol or caffeinated drinks - will help reduce symptoms. If symptoms are usually severe - consider stopping along the way for a couple of days, or traveling by ship. Adapt to local timetables immediately; this will speed up the body clock's adaptation to a new environment.

Home remedies A single light box and the OTC drug melatonin - allows travelers to avoid jet lag by resetting their circadian body clock before crossing several time zones, according to research published in The Endocrine Society's Journal of Clinical Endocrinology and Metabolism. Sunglasses - may reduce the effects of jet lag, according to a study. Strategic napping - The best time to nap (during or after the flight) is at nighttime in the time zone being traveled to. "Power naps" of around 20 minutes may help to reduce daytime sleepiness. Careful caffeine use - because caffeine increases alertness , if it is consumed during the morning it may help train the body to hit the correct rhythm. However, taking caffeinated products in the late-afternoon may interfere with getting to sleep at the correct time for the new time zone. Written by Christian Nordqvist Click the stars to rate this article Jet Lag: What It Is and How to Beat It Public / Patient Jetlag: Symptoms and Treatment References Symptoms The feelings of disorientation encountered as a result of crossing time zones are known as jet lag.

Symptoms include fatigue and general tiredness, inability to sleep at night, loss of concentration, loss of drive, headaches and general malaise. Jet-lag occurs when biological rhythms are disrupted as a result of rapid transitions across multiple time-zones. Such desynchronization of rhythms also occurs in nocturnal shift work employees who transfer to night shifts. A classical rhythm is represented by a sine wave, fluctuations occurring cyclically about a mean value rising to a peak and half a cycle later dropping to a trough. Twenty-four hour rhythms are known as circadian (about a day). An example of a biological rhythm is core temperature. We can find the characteristics of rhythms using the mathematical technique of cosinor analysis to determine the mean, the peak, the amplitude, and the time the peak occurs (the acrophase). Circadian Desynchronization Following a journey across multiple time zones the body's rhythms at first retain the characteristics of their point of departure. However, the new environment forces new influences on these cycles, the main factors being the time of sunrise and onset of darkness. The body attempts to adjust to this new context but core temperature is relatively sluggish in doing so. As a rough guide it takes about one day for each time zone crossed for body temperature to adapt completely.

The individual may have difficulty in sleeping for a few days, but activity and social contact during the day help in accelerating the adaptations of the arousal rhythm. Thus arousal adjusts more quickly than does body temperature to the new time zone. Until the whole spectrum of biological rhythms adjusts to the new local time, the performance of exercise may be below par. Allowing for individual differences, the severity of jet lag is affected by a variety of factors. In general, the greater the number of time zones crossed, the more difficult it is to cope. A 2-hour phase shift may have marginal significance but a 3-hour shift (e.g. British or Irish teams traveling to play European football matches in Russia or Turkey or a Californian sports team traveling to play on the east coast of the US) will entail desynchronization to a substantial degree. In such cases the flight times time of departure and time of arrival - may determine the severity of symptoms. The severity of symptoms may be worse 2-3 days after arrival than on the day immediately following disembarkation. Symptoms then gradually abate, but can still be acute at particular times of day.

There will be a window of time during the day when the period of high arousal associated with the time zone just left overlaps with the arousal high point at the new local time. This window may be predicted in advance and should be utilized for timing of training practices in the first few days at destination. Our observations on footballers traveling from Britain to the South Pacific indicate that morning training sessions suit players best over the first few days. Such a practice has also proved successful for cross-country runners. The direction of travel affects the severity of jet lag. It is easier to cope with flying in a westward direction compared to flying eastward. In flying westward the normal cycle is temporarily lengthened and body rhythms can extend in line with their natural freewheeling period of about 27 hours and thus catch up. Observations on traveling to Korea (9 hours in advance of British Summer time) and Malaysia (7 hours in advance of British Summer time) are that periods of 9 and 6 days respectively may be inadequate for jet lag symptoms to disappear. In contrast re-adaptation is more rapid on returning to Britain. When time zone shifts approach the maximum 12-hour change, there may be little difference between eastward and westward travel.

The direction of travel can be a relevant consideration when going from coast to coast to compete in North America. When going eastward the mean performance is depressed more and the peak performance declines more dramatically than is the case on traveling westward. The reason for westward travel being easier is because the natural period of circadian rhythms is greater than 24 hours, so each rhythm adapts more quickly when the day is artificially lengthened. Altering training times for a few days prior to travel to take into consideration the time of competition in another time zone is known to be beneficial. Young individuals have a better tolerance to desynchronization of rhythms, owing to a better regulation of biological clocks. Physical fitness also seems to play a role: active subjects demonstrate higher amplitudes in existing rhythms than age-matched controls, a difference indicative of superior regulation. But other than these factors, there has been little success in attempting to predict good and poor adapters to long haul flights. Furthermore, the fact that an individual escapes lightly from symptoms on one occasion is no guarantee that he or she will do so again on the next visit. Reducing Jet Lag Scheduling Travel If it is possible to do so, flights should be scheduled so that athletes arrive well in advance of competition.

One day for each time zone crossed does leave a cushion of safety, even traveling eastward. The time for adaptation may be shortened by exploiting the external factors that reset biological clocks: rest/exercise, darkness/ light, meals and social influences. The key is to tune in straight away to the external influences of the new environment. It may be beneficial to shop around to find the most convenient travel schedules. Consider departure from regional airports if appropriate and also alternative carriers. The routines prior to departure, on the plane, and after arrival, can be planned once the itinerary is established. In consequence coping with jet lag will not be the hit or miss affair it might otherwise be. Before and During Travel On lengthy journeys it is unlikely that any maneuvers will eliminate jet lag, but with careful planning the symptoms can be attenuated. In the week prior to departure it may be possible to adjust the time of arising and going to bed, the adjustment depending on the direction of flight. An alteration of more than two hours is likely to be unproductive, since this would interfere with the pattern of social and domestic engagements during the day. Besides, the major synchronizer of human circadian rhythms--natural daylight--remains unaltered.

The evidence from simply altering time of retiring to sleep is that shifting the sleep-wake cycle does alter rhythms in accord with the direction of the shift, but motor performance is compromised during the course of such adaptive changes. Manipulating the sleep-wakefulness rhythm prior to traveling abroad to compete therefore may not be the best strategy. Once flight times are known, a routine on the plane may be planned. In day time flights it will be necessary to stay awake, keep mentally active and perhaps watch the in-flight movie. On long haul flights that entail traveling during the night it will be necessary to get some sleep on the plane. The timing of this should be decided in advance so that some meals on board can be missed. Transit or transfer episodes en route should be taken into consideration. It is a good strategy to set one's watch to local time at the next point of landing, once on board the plane: in a single haul flight this would be the local time of the country of destination. The important thing is that the traveler mentally tunes in to the new local time straight away and adjusts behavior accordingly. To compensate for the dry air on board flight, copious rehydration is advised. Fruit juices are best, fizzy drinks should be avoided.

Alcohol should not be taken, since it acts as a diuretic (increases urine production) and also affects the normal circadian rhythm in renal function. Caffeine in coffee also stimulates water loss, and its arousal effect on the central nervous system means it should not be taken if sleep is desired. One suggestion is that the last meal prior to the time allotted for sleep should be high in carbohydrates and low in protein in order to induce drowsiness. Carbohydrates provide the substrate for serotonin, a neurotransmitter that regulates sleep. Caffeine and a low-carbohydrate high-protein breakfast would help raise the level of arousal and prevent a relapse into sleep. Athletes may feel stiff or cramped because of their restrained posture on board flight. They can perform isometric exercises for arms, trunk or legs while in their seats. It is even better to walk down the aisle of the plane and occasionally do flexibility or stretching exercises at the back of the plane. British sports teams traveling to Australia have used sleeping pills to induce sleep while on board. Although such drugs as benzodiazepines are effective in getting people to sleep, they do not guarantee a prolonged period asleep.

Besides, they have not been satisfactorily tested for subsequent residual effects on motor performances such as sports skills. They may also be counter-productive if administered at the incorrect time. A prolonged nap at the time the individual feels drowsy (presumably at the time that he or she would have been asleep in the time zone departed from) simply anchors the rhythms at their former phases and so resists the adaptations to the new time zone. Strategy upon Arrival On reaching the country of destination a key factor is to fit in immediately with the phase characteristics of the new environment. Athletes should already have worked out the local time for their disembarkation. There may be other environmental factors to consider such as heat, humidity or even altitude. Having traveled westward, players may be allowed to retire to bed early. Early onset of sleep will be less likely after an eastward flight. In this case a light training session on that evening would be helpful in instilling local cues into the rhythms. Besides, there is some evidence that exercise does speed up the adaptation to a new time zone. For the first few days in the new time zone, training sessions should not be all-out efforts.

Skills requiring fine co-ordination are likely to be impaired and this might lead to accidents or injuries if, for example, games players conducted sessions with the ball too strenuously. Where a series of tournament engagements is scheduled, it is useful to have at least one friendly match during the initial period (before the end of the first week) in the overseas country. In this period of adaptation a few caveats are noted. Alcohol taken late in the evening is likely to disrupt sleep and so is not advised. The alternation of feasting and fasting recommended for commercial travelers in the USA is unlikely to gain acceptance among footballers. Nevertheless they could benefit from biasing the macronutrients in their evening meal largely towards carbohydrates. These would include vegetables with a choice of chipped, roast or baked potatoes, pasta dishes, rice and bread. These should include sufficient fiber to safeguard against constipation. In the early days in the new country athletes should be discouraged from taking prolonged naps. A nap at the time they would have been asleep had they stayed at home would make subsequent sleep more difficult and retard the adjustment of the major biological clocks to the new regimens.

Exposure to bright light, preferably natural daylight, is a useful antidote to drowsiness in such circumstances. Taking drugs can alter biological clocks, depending on the time they are taken. Caffeine (in coffee) and theophylline (in tea) are stimulantsm of the central nervous system. Taken in the evening they would help in recovery after flying eastward and in the afternoon after flying westward. The minor tranquilizers, benzodiaepines, affect neurotransmitters that have a role in arousal. These include serotonin, noradrenaline, acetylcholine and gamma-aminobutyric acid (GABA). As already indicated, they are effective in inducing sleep but not necessarily good in ensuring the state of sleep. Also hangover effects cannot be excluded, even in some so-called short-acting hypnotics. Administration of melatonin, which is a pineal gland hormone, has shown good results in treating Scandinavian patients suffering depression in the winter. This clinical condition is known as seasonal affective disorder. The lack of stimulus from natural light for the pineal gland to secrete melatonin is a recognized cause of this entity. Prolonged exposure to bright artificial light has also proved effective in those patients.

Subjects who took melatonin tablets on a trip from Britain to Australia experienced a reduction in jet-lag symptoms, improvements in sleep quality, and a faster readjustment of cortisol and melatonin rhythms. These findings received further support from results of a simulated eastward flight across nine time zones. It seems that administration of melatonin in the afternoon or evening causes phase advances of circadian rhythms whereas a phase delay (required after a westward flight) results from administration at night or early morning. However, toxic side-effects of this substance cannot be discounted and besides, it is not yet readily available in tablet form. There is also a suggestion that the amino acid tryptophan is helpful in coping with jet-lag. It is a precursor of the sleep hormones, but there is no evidence that it improves the quality of sleep. Besides, it has achieved bad publicity in the early 1990s due to impurities being found in commercially available products and its use is no longer recommended. It is more effective to use light or behavioral measures to resynchronize circadian rhythms. Natural daylight and bright artificial light help to increase or maintain arousal as well as contribute to returning endogenous rhythms. For athletes exercise is a powerful resynchronizor.

It stimulates catecholamines and alertness. It is recommended, even on the day of arrival, except late in the evening local time. Exercise at a light intensity is adequate for stimulating resynchronization of rhythmic characteristics as exercise that is too strenuous may disrupt rather than promote sleep. References 1. de Looy, A.E., D.S. Minors, J. Waterhouse, T. Reilly and D. Tunstall-Pedoe. The Coach's Guide to Competing Abroad. Leeds: National Coaching Foundation, 1988. 2. Minors, D.S., J.M. Waterhouse, and L.R. Smith, The body clock: jet-lag, physical and psychological rhythms. In: Intermittent High Intensity Exercise: Preparation, Stresses and Damage Limitation, D.A.D. Macleod, R.J. Maughan, C. Williams, G.R. Madeley, J.C.M. Sharp and R.W. Nutton (Eds.). E. London: F.N. Spon: 1992, pp. 75-90. 3. Reilly, T. Circadian rhythms and exercise.

in: Exercise, Benefits, Limits and Adaptations, D. Macleod, R.J. Maughan, M. Nimmo, T. Reilly and C. Williams (Eds.). London: E. and F.N. Spon, 1987, pp.46-66. 4. Reilly, T. and S. Mellor, Jet-lag in student Rugby League players following a near maximal time-zone shift. In: Science and Football, T. Reilly, A. Lees, K. Davids and W.J. Murphy (Eds.). London: E. and F.N. Spon, 1988, pp. 249-256. 5. Olympic Committee. From the U.S. to Seoul. Colorado Springs: U.S. Olympic Committee, 1988. Jet lag - Causes - NHS Choices Jet lag - Causes Jet-lag Prevention Causes of jet lag Jet lag occurs when the body has to adapt to a new light-dark schedule and normal daily routine after crossing several time zones.

Symptoms such as sleep disruption and tiredness are the result of your body finding it difficult to adjust to your new location's time zone because your body clocks can't adjust immediately. Circadian rhythms Circadian rhythms are 24-hour variations in body functions, which are controlled by "biological clocks" in your body. Jet lag occurs when your body's circadian rhythm needs to re-align itself with a different light-dark schedule and daily routine. The body’s cells have their own clocks which interact with each other and are controlled by a "master" 24-hour clock in the brain. The master clock helps to keep all the body clocks synchronised with each other and with the light-dark rest-activity schedule. Your body is used to a regular routine of light and darkness at certain times of the day. However, when you travel to a new time zone, this routine is disrupted. Air travel makes it possible to cross several different time zones in just a few hours. After travelling so quickly, your body has to catch up and re-establish its circadian rhythm. It takes time for your body to adjust the circadian rhythms to new times of light, darkness and eating. East and west Symptoms of jet lag are usually more severe when travelling east.

This is possibly because your body finds it easier to adapt to a longer day (you "gain time" travelling west) than a shorter one (you "lose time" travelling east). Your body is able to adapt better when you travel west because you're extending your day rather than shortening it when you travel east. It's usually easier to delay sleep for a few hours than trying to force sleep when you're not ready to. General travel fatigue Factors that can contribute to general travel fatigue (which isn't the same as jet lag) include: dehydration (not drinking enough water) drinking alcohol and caffeine during the flight lack of sleep stress being over 60 years of age It's also thought that high altitude and changes in cabin pressure may cause some symptoms that are similar to those of jet lag, regardless of travel across time zones. Although the above factors can contribute to general travel fatigue, there's no evidence to suggest that they can make the symptoms of jet lag worse. Page last reviewed: 24/11/2014 Jet Lag | Health | Patient Jet Lag 1254 Jet lag is the term used for the collection of problems we experience after flying across several time zones.

Many of the symptoms are due to the changes in our sleep schedule as we adapt to a different time zone. The symptoms improve over a few days. There are some tactics to try which may help you recover from jet lag more quickly. What is jet lag? Jet lag refers to a collection of symptoms which arise from crossing several time zones while travelling by air. It is called "jet" lag because it only occurs following rapid travel. Before the advent of fast air travel, journeys were slow enough for us to adjust gradually to different time zones. The main symptoms of jet lag are due to our sleep schedule being disrupted. Why does jet lag occur? Many of the systems in our bodies are controlled by our internal clock. The normal cycle of sleeping at night and being awake in the daytime is called a circadian rhythm. All living beings, even plants, function with this rhythm controlling an internal clock. The rhythm is created by the cycle of daylight and darkness. When travelling, it takes some time for your internal clock to adjust to the new time zone and to the different hours of daylight. This adjustment time causes the syndrome known as jet lag. Normally, feeling sleepy at bedtime is partly due to a hormone called melatonin.

Melatonin is made by a part of our brain called the pineal gland. Most melatonin is produced when it is dark. Light blocks production of melatonin. When travelling, it takes a few days for the correct cycle of melatonin increases and decreases to be re-established. What are the symptoms of jet lag? The most common symptoms of jet lag are related to sleep. You may have difficulty getting to sleep at bedtime and struggle to wake up in the morning. Or you may be tired long before bedtime and wake up while it is still night and too early to get up. This will depend on whether your destination time is ahead or behind the time at the start of your journey. This in turn depends if you are travelling west to east, or east to west. The effect of this difficulty with sleeping is feeling tired and not being able to function as well as usual. Both physically and mentally, you may not be able to function as normal. Specifically this might result in: Feeling tired or exhausted. Read more blog posts Who is affected by jet lag? If you are travelling over three time zones or fewer, jet lag is not usually a problem. It usually affects people travelling across more than three time zones.

So if the time at your destination is three or more hours different to that at the start of your journey, you are likely to experience jet lag. The more the time difference, the greater the problem jet lag is likely to be. If you are travelling west to east, you are more likely to have problems with jet lag. In this direction, you have to advance your time clock, which is more difficult than delaying it. In this direction, you have to try to go to sleep when you are not tired. If you are travelling more slowly, by boat or car, your body clock will be able to adjust gradually. Jet lag only affects people travelling quickly across several time zones. People who travel frequently, particularly airline pilots and crew, are most likely to have problems with jet lag. Others may need to fly frequently as part of their job. It can be a problem for athletes competing in different parts of the world. Performance in sport or other jobs may be less good due to jet lag symptoms. More related content What is the best way to manage jet lag? Jet lag gradually subsides on its own after a few days, as your body clock adapts to the new time zone. There are a number of strategies which may help you get over it more quickly.

Some of these strategies are: After arrival at your destination, try to change your schedule to the new time zone as quickly as possible. Avoid going to sleep until it is a reasonable bedtime for the new time zone. Set alarms to stop you oversleeping in the morning. Caffeine-containing drinks such as coffee or cola may help keep you awake until it is a reasonable time to go to sleep. However, avoid these in the six hours before you plan to go to sleep, or they may interfere with sleep. Prior to going to bed, try to relax. Avoid large meals, heavy exercise and exciting books or films before sleeping. Avoid caffeine and alcohol before bedtime, as these may interfere with sleep. Try to keep the room in which you are sleeping dark and quiet. On the plane, only try to sleep if it is a normal sleep time for your destination. Eye shades or ear plugs may help if you are trying to get to sleep. Limit alcohol on the plane. Consider gradually adapting your sleep schedule slightly towards the destination times in the few days before departure. For example, start going to bed and getting up an hour or two earlier or later than usual, so the difference is not so big when you arrive.

In the daytime at your destination, expose yourself to outside natural light as much as possible. This will help your internal clock adjust. If you are only in the new time zone for two to three days it may be easier to stay on your original timings. Eat and go to sleep at times that would be normal for you, even if they aren't the right times for the place you are now in. This may not be practical for everybody, as it depends on what you want or need to do while you are away. Other strategies to try to change exposure to light are sometimes used. There is not yet much evidence to assess how well these work. Outdoor natural light is the best but some people use light boxes inside to try to increase the amount of light. The idea is that this cuts down the amount of natural melatonin released by the brain. This will then delay the time when you start to feel sleepy. However, more studies need to be done to find out what would be the best time to use light therapy and how long for. This would vary depending on which direction you have travelled and the time difference between the start and finish. Another technique used by some people is blocking out certain types of light.

Shortwave or "blue" light is thought to be most important in stopping melatonin being released. Therefore, glasses which block blue light, worn at certain times, can help you release melatonin earlier than usual. This would be helpful if you are trying to bring forward the time you go to sleep - for example, after travelling west to east. Related Wellbeing See all Wellbeing Are there any medicines to help with jet lag? Most people do not need medicines to help with jet lag and there are no treatments specifically licensed for this. Occasionally it may be necessary to take sleeping tablets to help you get back into a sleeping pattern. Sleeping tablets are addictive, so they are only for occasional use and for people who are severely affected by jet lag. Another tablet sometimes used is melatonin . This is a tablet form of the natural melatonin hormone which your brain produces. There have been studies which show melatonin helps the symptoms of jet lag, particularly for people travelling east. However, in the UK melatonin is not licensed for jet lag. This is because there is not yet enough evidence about any side-effects, particularly if it has to be taken regularly. It is also not yet known what dose should be used or the time at which it should be taken.

Circadian Rhythms Fact Sheet - National Institute of General Medical Sciences National Institute of General Medical Sciences NIGMS Home > Science Education > Circadian Rhythms Fact Sheet Circadian Rhythms Fact Sheet En español What are circadian rhythms? Circadian rhythms are physical, mental and behavioral changes that follow a roughly 24-hour cycle, responding primarily to light and darkness in an organism's environment. They are found in most living things, including animals, plants and many tiny microbes. The study of circadian rhythms is called chronobiology. Are circadian rhythms the same thing as biological clocks? No, but they are related. Our biological clocks drive our circadian rhythms. What are biological clocks? The biological clocks that control circadian rhythms are groupings of interacting molecules in cells throughout the body. A "master clock" in the brain coordinates all the body clocks so that they are in synch. What is the master clock? The "master clock" that controls circadian rhythms consists of a group of nerve cells in the brain called the suprachiasmatic nucleus, or SCN.

The SCN contains about 20,000 nerve cells and is located in the hypothalamus, an area of the brain just above where the optic nerves from the eyes cross. Do circadian rhythms have a genetic component? Yes. Researchers have already identified genes that direct circadian rhythms in people, fruit flies, mice, fungi and several other model organisms used for studying genetics. Does the body make and keep its own circadian rhythms? Circadian rhythms are produced by natural factors within the body, but they are also affected by signals from the environment. Light is the main cue influencing circadian rhythms, turning on or turning off genes that control an organism's internal clocks. How do circadian rhythms affect body function and health? Circadian rhythms can influence sleep-wake cycles, hormone release, body temperature and other important bodily functions. They have been linked to various sleep disorders, such as insomnia. Abnormal circadian rhythms have also been associated with obesity, diabetes, depression, bipolar disorder and seasonal affective disorder. How are circadian rhythms related to sleep? Circadian rhythms are important in determining human sleep patterns. The body's master clock, or SCN, controls the production of melatonin, a hormone that makes you sleepy.

Since it is located just above the optic nerves, which relay information from the eyes to the brain, the SCN receives information about incoming light. When there is less light—like at night—the SCN tells the brain to make more melatonin so you get drowsy. How are circadian rhythms related to jet lag? Jet lag occurs when travelers suffer from disrupted circadian rhythms. When you pass through different time zones, your body's clock will be different from your wristwatch. For example, if you fly in an airplane from California to New York, you "lose" 3 hours of time. So when you wake up at 7:00 a.m., your body still thinks it's 4:00 a.m., making you feel groggy and disoriented. Your body's clock will eventually reset itself, but this often takes a few days. How do researchers study circadian rhythms? Scientists can learn about circadian rhythms by studying humans or by using model organisms that have similar "clock" genes. Basic researchers doing these experiments can control the subject's environment by altering light and dark periods and then look for changes in gene activity or other molecular signals. How does circadian rhythm research contribute to human health?

Understanding what makes biological clocks tick may lead researchers to treatments for sleep disorders, jet lag and other health problems. Learning more about the genes responsible for circadian rhythms will also enhance our understanding of biological systems and the human body. NIGMS is a part of the National Institutes of Health that supports basic research to increase our understanding of biological processes and lay the foundation for advances in disease diagnosis, treatment and prevention. For more information on the Institute's research and training programs, see . Content reviewed November 2012 Want to use this content on your website or other digital platform? This fact sheet and others are available for syndication through the HHS Syndication Storefront . For more information on how syndication works, see the HHS Syndication Storefront Questions and Answers page . Jet lag disrupts sleep by throwing two neural centers out of sync Jet lag disrupts sleep by throwing two neural centers out of sync Published on April 19, 2009 at 11:57 PM · No Comments New research by scientists in the U.S. has revealed that the disrupted sleep which results from jet lag and shift work occurs in two separate but linked groups of neurons below the hypothalamus at the base of the brain.

The fatigue caused by jet lag and shift work is a direct result of disruption to the body's normal rhythms and is a problem for both travellers and those who work in rotating shifts. The symptoms of jet lag include fatigue, sleepiness, digestive upsets, impaired judgement and decision making, memory lapses, irritability and apathy. The body is synchronised to night and day by the effect of sunlight through brain chemicals or neurotransmitters, especially melatonin and many bodily processes are set by this 24-hour physiological ‘clock’ - these include temperature, hormones, digestion, heart rate, blood pressure and brain states. This changing rate of activity over each 24-hour period is called the circadian rhythm (‘circadian’ means approximately one day). The new research from the University of Washington (UW) shows the disruption occurs in two separate but linked groups of neurons in a structure called the suprachiasmatic nucleus, below the hypothalamus at the base of the brain - one group is synchronized with deep sleep that results from physical fatigue and the other controls the dream state of rapid eye movement, or REM, sleep.

The ventral, or bottom, neurons receive light information directly from the eyes and govern rhythms in tune with periods of light and dark - while the dorsal, or top, neurons do not receive direct light information and so govern rhythms as a more independent internal, or circadian, biological clock. Dr Horacio de la Iglesia, a UW associate professor of biology, and the lead author of the study, says it appears that some of the body's rhythms are "more loyal" to the ventral neurons and others are much more in tune with the dorsal neurons. In normal circumstances the two neuron groups are synchronized with each other, but disruptions such as jet travel across time zones or shift work can throw the cycles out of kilter. Deep sleep is most closely tied to light-dark cycles and typically adjusts to a new schedule in a couple of days, but REM sleep is more tied to the light-insensitive dorsal neurons and can be out of sync for a week or more. Related Stories Zoned out: how to minimize jet lag - Reverie Zoned out: how to minimize jet lag Jul 27, 2016 By Dr. Benjamin Smarr Summer travel season is in full swing. Maybe you’re jetting off to the coast.

Or to Rio for the Olympics. Many of us also go on business trips from time to time, or even all the time. So jet lag happens. Feeling tired after a serious time-zone change is a real thing. You don’t want to waste precious vacation time or productivity by feeling out of it for several days, nor do you want to feel like a zombie when you return home. While it’s probably inevitable that you’ll feel a bit tired while adjusting to a time-zone change, there are ways to mitigate the effects. What causes jet lag? Jet lag occurs when there is a sudden change in the alignment of environmental time cues, notably sunlight, relative to the body’s internal timing, which is also referred to as the circadian rhythm. So flying across time zones tends to have a similar effect as working the afternoon or night shift. Both situations cause the individual and his or her environment to be out of sync. The reason jet lag causes negative effects is that the body has more than one circadian rhythm. Instead, every cell keeps its own internal time. Local networks of cells (tissues) allow pretty good coordination within organs.

For example, even though individual liver cells keep time internally, most liver cells align to each other so that you can think of “liver time” as a thing. However, time is much less well coordinated across different organs. Your eyes are windows to the brain Cells in your eyes have their own individual clocks which run on their own eye time and are sensitive to light. And these are particular culprits in jet lag, because they are the key communicator of light cues to your brain, since your brain doesn’t get any light exposure itself. So while your eyes are communicating directly to your brain about light, they’re not communicating to the clocks in your liver, bones, etc. Those organs and tissues tend to rely on other cues, strongly influenced by metabolic cues, like when you eat, go for a run, etc. Further complicating the jet lag equation is that your eyes and brain, because they are more affected by light, generally adjust within a day to your new setting. However, your other organs and tissues can only catch up to the new time at the rate of about an hour a day.

And they adjust even more slowly if they get conflicting information about time, which happens if your eating and exercise habits don’t align with the light in your new environment. What these different rates of adjustment mean is that while you get used to a new time, the clocks in your body fall out of their normal alignment. As long as the normal alignment of organ times is disrupted, your organs will be doing things when other organs aren’t ready for them – like your stomach making acid when you’re not actually about to eat, giving you ulcers or acid reflux. When your body clocks are out of sync The misalignment of body clocks, which doctors and scientists call internal desynchrony, is what makes us feel bad when we have jet lag. As long as our body systems don’t line up, it is normal for us to feel unwell. It’s the body’s way of telling us that something is not right. Again, we can expect to feel that way about one day per hour of time zone change, given how long it takes our organs to move into alignment. It may take even longer if you’re traveling to an area that’s a much higher altitude than where you currently are. So what can you do to minimize jet lag’s negative effects?

Get a head start on adjusting to the new time To some extent, you can get ahead of your trip by adjusting your timing at home. Go to bed a little earlier or later, maybe shift your eating, waking and sleeping schedules an hour toward the time zone to which you’ll be traveling. Sports teams are beginning to do this more. They are training at the time of day that will be local time for the event, so that when the athletes fly and play the same day, their bodies are expecting to play at the right (internal) time. For example, athletes in New York might practice at 7pm in if they plan to fly to California for a 4pm game in a few days. Get all your timing cues aligned Sleep, exercise, and eat on local time so that your body gets the same time information to all organs, no matter what cues they’re sensitive to. Getting bright light in the day is also important, just like making sure it’s dark when you sleep. Going outside helps with the former, and using a sleep mask can help with the latter, especially if you don’t quite sleep on local time the first day or two. Earplugs can also be beneficial.

Give yourself a break Internal desynchrony disrupts your body as well as your ability to think and act. For the first 24 hours, you’re likely to be a bit under the weather, no matter what you do. So build in a day to relax when you arrive. Taking it easy for a day allows your body to focus on realigning itself and recovering, which is hard to do if you put additional stress on it by going gung-ho when you first arrive. Chilling out poolside isn’t lazy; it’s a smart move and an investment for the following days. Accept that which you cannot control We do not know of any superhumans outside of the movies. A normal human being is going to feel fatigued for a few days when traveling across time zones. So be aware, follow these tips and make the most out of your trip. Dr. Benjamin Smarr studies the temporal structures that biological systems make as they move through time. An NIH research fellow at UC Berkeley, his work focuses on understanding how physiological dynamics like sleep, circadian rhythms, and ovulatory cycles are shaped by the brain, and how disturbances to those cycles gives rise to disease. Dr.

Smarr is also an advocate for scientific outreach, and routinely gives public lectures and visits K-12 classrooms to help promote the idea that by understanding the biology that guides us, we can live more empowered lives. Jet Lag - Causes, Symptoms, Treatment, Diagnosis - Canada.com Health Column The Facts Jet lag occurs when there's a mismatch between the time of a person's internal clock and the events affecting that person as a result of rapid travel between different time zones. Jet lag can make travellers fatigued when they want to be alert, or can keep them from getting a good night's sleep, depending on whether they have travelled "forward" (eastbound) or "backward" (westbound) in time. Causes You don't experience jet lag from flying between the north and south. It is brought on only by flying a long distance (at least two time zones) going east or west. One may feel unwell getting off a plane from Toronto to Miami, but that's not jet lag - it is the fatigue that comes naturally with travel. We all have an internal timekeeping system (the circadian clock) that's centred in the hypothalamus, a part of the lower brain.

The hypothalamus receives signals from the eyes, telling it whether it's light or dark. According to this information, the hypothalamus tells the nearby pineal gland to secrete or stop secreting a hormone (called melatonin) that governs wakefulness and sleepiness. Melatonin is secreted when it's dark. The more melatonin in your system, the sleepier you are. Research has shown that turning on the lights at night can immediately stop melatonin production. When we fly across time zones, we enter a world in which everything is happening at the wrong time. The hypothalamus will pick up the new light cues and reset the clock, but it usually takes a day or two. This interval is known as jet lag. Jet lag is worse when travelling east than when travelling west. Research studies with people who are blind and people who have been isolated from daylight shows that the natural day of the body clock is actually a bit longer than our day by the clock, averaging about 25 hours. This is why so many people find it easier to stay up late than to go to bed early. It is also why eastward travel causes more trouble for the body clock.

The body can readjust by about 90 minutes a day going backwards; that is, one can easily go to bed 90 minutes later each night for a few days. The body can only adjust about 60 minutes forward a day. Therefore it takes about 2 days to adjust to 3 hours of westward travel, but 3 days to adjust to 3 hours of eastward travel. Symptoms and Complications The primary symptom of jet lag involves the feeling that everything is happening at the wrong time. Meals and bedtime come too early or too late, depending on whether one has gone east or west. With minor shifts of 2 hours or less, travellers probably won't even notice the effect. They start to adjust as soon as they land, but it takes a day or two, sometimes longer, depending on the distance travelled and number of time zones being crossed. The most common physical symptoms of jet lag include: apathy restless sleep (sometimes with frequent awakenings) upset stomach diarrhea or constipation Symptoms such as stuffy nose, aching muscles, swollen ankles, headache, and nausea are usually due to flying and not to jet lag. These symptoms usually disappear soon after landing, which is when jet lag is just beginning.

Jet lag is usually a minor nuisance, but it is associated with some risks. Women who fly a great deal, especially flight attendants, often find that their menstrual cycle is disrupted. The symptoms of peptic ulcer disease can also be made worse by jet lag. This is because the stomach releases acid when the brain thinks it's mealtime. If there's nothing in the stomach, the acid is more corrosive. People who take insulin for diabetes should talk to their doctor about slowly changing their insulin schedule before travelling across several time zones. Carrying a glucose monitoring device (to measure the amount of sugar in the blood) and using it frequently is especially important under these circumstances. Treatment and Prevention You're best off adjusting to the new time as soon as possible. If your schedule permits, it may be useful to begin the time shift even before departure. For 2 or 3 days before departure, go to bed a little earlier or later each night. Go to bed a little earlier if you're travelling east, and go to bed later if you're travelling west. Some people take melatonin* supplements for jet lag. Recommendations on how to take melatonin vary.

In general, melatonin may be taken at an appropriate dose (between 0.1 mg and 10 mg) at bedtime for a few nights starting the day you arrive. If you are traveling eastbound, you may begin to take melatonin at bedtime for a few days before departure. Ask your health care provider when you should start taking melatonin, at what dose, and for how long. There are studies showing that melatonin can help minimize jet lag, but none prove it is safe to take for long periods of time. Some experts worry that routinely taking this hormone in pill form may reduce the ability of the pineal gland to produce your own internal supply of melatonin. People who travel a great deal and use melatonin frequently are running unknown risks. In most instances, jet lag isn't serious enough to justify this type of risk. Talk to your doctor if you have concerns about melatonin. If you choose to try melatonin, ensure that the product you buy has a natural health product (NHP) number. This will ensure that the product meets Health Canada's standards of safety and quality. Recent studies show that changing one's exposure to outdoor light may improve jet lag considerably.

This is because sunlight affects the stimuli (zeitgabers) to the eye, which then affects pineal gland. You can also buy light boxes that can be used when outdoor light is not available. It's a good idea to talk to a health care professional about whether light boxes are right for you and how to use them most effectively. For eastbound travel crossing more than six time zones, exposure to afternoon light (whether or not the sun is shining) is helpful. For travel crossing less than six time zones, morning sunlight is useful. The opposite is recommended for westbound travel. Some business travellers use a very short-acting sedative medication to sleep on aircraft, thus reducing the risk of jet lag. Ask your doctor whether this is a good option for you. Other suggestions to reduce the impact of jet lag while travelling include: drinking plenty of water eating small meals frequently and choosing lighter foods like fruit and vegetables ensuring you get enough sleep before you leave - a sleep deficit or "debt" will make jet lag worse limiting or avoiding alcohol and caffeinated drinks trying to nap whenever you feel sleepy wearing loose, comfortable clothing walking around the airplane cabin whenever possible *All medications have both common (generic) and brand names.

The brand name is what a specific manufacturer calls the product (e.g., Tylenol®). The common name is the medical name for the medication (e.g., acetaminophen). A medication may have many brand names, but only one common name. This article lists medications by their common names. For information on a given medication, check our Drug Information database. For more information on brand names, speak with your doctor or pharmacist. More on Body and Health Symptoms and Treatments of Circadian Rhythm Disorders Symptoms and Treatments of Circadian Rhythm Disorders Search the site Symptoms and Treatments of Circadian Rhythm Disorders Irregular Sleep Patterns May Cause Insomnia, Excessive Daytime Sleepiness By Brandon Peters, MD - Reviewed by a board-certified physician. Updated April 06, 2016 Difficulties falling asleep or staying awake at the proper times may suggest you have a problem with your biological clock called a circadian rhythm disorder, but what are circadian rhythm disorders? These common conditions may include wanting to sleep at an atypical time, irregular sleep patterns, and even jet lag or shift-work sleep disorder. Discover how these disorders contribute to symptoms of insomnia, poorly timed sleepiness, and effects on daytime function.

Review the most effective treatments, including light therapy and melatonin. Features and Symptoms of Circadian Rhythm Disorders The circadian rhythm disorders share common characteristics. They occur when your internal biological clock becomes out of sync with external time cues such as the natural dark-light cycle. As a result, your desire to sleep may shift away from nighttime when most people naturally sleep. Therefore, you may have difficulties with insomnia or excessive daytime sleepiness . The inability to sleep at the expected time coupled with sleepiness during wakefulness may lead to difficulties with job and school performance. For a better understanding of this, review the disorders and examples provided below: Delayed Sleep Phase Syndrome Characterized as night owls, people with delayed sleep phase syndrome often have difficulty falling asleep. This insomnia may result in a natural ability to fall asleep that is closer to 2 to 4 AM. It is also extremely difficult to wake up, resulting in profound morning sleepiness. The preferred wake time may be observed on weekends or days off and is usually from 10 AM to Noon. It is estimated that about 7% of people are night owls, and it usually begins in teenagers and can persist throughout life.

About 40% of night owls will have a family history of the disorder. Advanced Sleep Phase Syndrome The opposite of night owls, people with advanced sleep phase syndrome are sometimes describes as being morning larks. They fall asleep very early and wake too early as well. This advance in the timing of sleep is usually 3 hours earlier than typical. For example, someone who is affected may fall asleep at 7 PM and wake by 3 AM, far earlier than desired. This condition may affect 1% of adults and can be confused with other causes of early morning awakenings such as sleep apnea. Nonentrained (Non-24) Circadian Rhythm Sleep Disorder Non-24 rarely occurs in sighted people, but it affects 50 to 73% of blind people. In the absence of effective synchronization of their internal clock with light exposure, they run a day-night pattern that is determined genetically and often runs a little long. For example, the internal clock might run at 24 1/2 hours in length. Therefore, the desire for sleep and waking occurs 30 minutes later each day.

This results in a shifting sleep schedule with increasing insomnia and daytime sleepiness that unfolds over several weeks as the misalignment continues. Irregular Sleep-Wake Rhythm Though the exact prevalence is unknown, people with neurologic disorders like dementia or children with intellectual disability may more likely experience an irregular sleep-wake rhythm. This may be worsened among those who are institutionalized with inadequate exposure to natural day-night light patterns. It seems to occur when the circadian rhythm degenerates or becomes unmoored from natural influences. Sleep becomes very fragmented, often with 3 or more periods of sleep lasting a few hours and scattered throughout the 24-hour period. Irregular bouts of sleep may be accompanied by insomnia and excessive daytime sleepiness complaints. The total amount of sleep is often normal. Jet Lag Jet lag occurs after travel across multiple time zones. Its intensity may depend on the length of the trip and how quickly the travel occurs. It is generally easier to travel shorter distances, slower, and in a westward direction. It takes about 1 day to adjust to each time zone crossed. Beyond trouble with insomnia and sleepiness, jet lag can also contribute to symptoms of malaise (feeling unwell) and an upset stomach.

Shift-Work Sleep Disorder People who work when they are meant to be asleep are at risk of having difficulty sleeping during the daytime and trouble staying awake during the night. This can have important safety consequences with increased risks of accidents. There also may be long-term effects, such as an increased risk of developing colorectal and breast cancer among shift workers. Diagnosis and Treatment of Circadian Rhythm Disorders Circadian rhythm sleep disorders often result when the desire to sleep is misaligned with the day-night cycle. This may occur in medical conditions such as blindness or as the result of long-distance air travel or even from working the graveyard shift. Fortunately, the conditions are easily diagnosed by using sleep logs and actigraphy and effective treatments including behavioral changes, light boxes , and melatonin can be helpful. If you feel like you may be suffering from the ill effects of a circadian rhythm disorder, speak with a board-certified sleep physician about your concerns and discover the effective treatment that you need. Source: American Academy of Sleep Medicine. "International classification of sleep disorders: Diagnostic and coding manual." 2nd ed. 2005. Continue Reading

Question: What is disrupted when "Jet lag" occurs?
Answer: Circadian rhythms