Jetlag

( Circadian dysrhythmia - circadian rhythm ) as jet lag ( from the English by jet, jet plane ' and was, time difference ') after a long-haul flights occurring over several time zones disorder of the sleep -wake cycle is called. It is sometimes referred to as the German transmission and as jetlagged.

Jetlag belongs to the classification system for sleep " International Classification of Sleep Disorders " ( ICSD -2) to the Circadian sleep-wake rhythm disorders and is "Type Circadian sleep-wake rhythm disorder, jet lag " in this context as well.

After the quick travel across several time zones, the body clock is out of sync with the new local time. Light and darkness occur at unusual times; the natural rhythms such as food and sleep, hormone production, body temperature coming out of the clock. Since the internal clock can not adjust to a new local time short, different physical and psychological ailments of shape. The prevention and treatment are particularly behavioral recommendations that help to adjust to the time zone of the destination.

• 4.1 General behavior recommendations
• 4.2 Influence of light
• 4.3 Melatonin supplements
• 4.4 drugs
• 4.5 nutrition

Discomfort

The most common symptoms of jet lag are sleep disorders in the form of initiating and maintaining sleep, fatigue, dizziness, mood swings, loss of appetite and decreased energy in physical, manual and cognitive demands. The subjective symptoms usually disappear after a few days, during the match objectively measurable in the sleep laboratory parameters, body temperature and hormone status only after a long time (up to two weeks). Although almost all travelers perceive complaints with a time lag of more than five hours, the severity and the recovery of which is individually very different. Although the influence of many factors has not been systematically investigated the complaints at a lower age seem to be more pronounced.

Influence the direction of flight

The direction of flight experience, has an influence on the severity of jet lag, and this is usually felt more strongly during air travel to the east. The internal clock usually does not run exactly in the 24 -hour clock, but with slightly longer stroke phases, so it is easier for many people to stay up longer than get up earlier. Flights to East demand accelerated, thus reducing cycle phases (corresponding to early sunrise or sunset, and thus getting up earlier ), Flights to West, however, extended clock phases (equivalent to delayed sunrise or sunset, and thus extended up late ).

• To the west of Frankfurt am Main to Denver eight time zones

• Eastward from Munich to Seoul eight time zones

After the flight westward shown in the table, it is equally so, as if you were the night remained monitored and only by 6 clock in the morning went to bed, so eight hours later than normal. According to the illustrated flight eastward, it is as if one would also be the night remained wide awake, but only went to bed by 14 clock, or 16 hours later than usual.

Basics

The aim of the research is to explore the understanding of the underlying mechanisms of jet lag. These are methodological reasons, primarily animal experiments.

Circadian rhythm

The most important timing in humans is the light-dark rhythm of the day. The mechanisms underlying this basis, were remarkably stable during evolution and typically consist of self-regulating cycles in which specific proteins (so-called " Uhrproteine ​​" ) control their own gene expression. Such regulations retain the 24 -hour cycle of RNA and protein expression. Despite the retention of these mechanisms now questions were the same, according to the relevance, after which it could be proved that the oscillation important " clock " genes can be eliminated without loss of essential internal clock. In the early 1970s could be documented by Seymour Benzer in the fruit fly Drosophila melanogaster genetically predisposed to different timings of the circadian rhythm.

Internal clock (mammals including humans)

In mammals, the circadian rhythm is determined by an internal clock, whose seat was in a part of the hypothalamus, the suprachiasmatic nucleus, identified. The circadian rhythm affects numerous body functions such as body temperature, blood pressure, urine production and hormone secretion, and could also be detected in individual cells. The internal clock usually does not run exactly in the 24 -hour clock. You will, under normal, stable conditions daily by exogenous timer (eg living conditions, timing of meals and bright light ) influences; so it remains synchronized under normal circumstances. These timers are also important in the readjustment in case of jet lag, the melatonin is involved. This is augmented in the dark and in bright light - paid reduced - eg daylight. The most important timing in humans is the light-dark rhythm of the day. The circadian rhythm is changing only slowly, so that it is not changed abruptly in spite of a unique disorder of sleep.

Basic research on animal models

Although the jet lag is very common these days, so far only a few high-level studies have been busy. Shift work and jet lag often reduce mental performance and increase the risk for health problems. Examples of these digestive problems, stomach ulcers, sleep disorders and cancers are called in the literature. Some of these problems take over the working years, as a result of the aging process or an accumulation ( accumulation ) of damage, too. Also inherently assumes the morbidity rate to over the years; However, the role played by the internal clock here, is so far poorly understood.

When a mammal is exposed to bright light and this information is relayed to the suprachiasmatic nucleus, where glutamate and PACAP are ( pituitary adenylate cyclase activating polypeptide ) are released that reach the local nerve cells ( neurons) and lead to an adjustment of the internal clock. Delayed light in the early night phase and light in the late phase accelerates this adjustment. In both cases the increase intracellular calcium ion level and the activity of certain enzymes, such as phosphatases and kinases (including the mitogen-activated protein kinases, and the Ca 2 / calmodulin-dependent protein kinase ). This process is dependent on CREB ( cAMP response element -binding protein ) and ELK- 1 (member of ETS oncogene family) and the " Uhrgenen " (English Circadian Locomotor Output Cycles CLOCK for out of order ). In contrast to these nocturnal animals involved processes respond during the day also to stimuli such as saline injections, involuntary activities in a new environment, or even darkness. In these cases, the cAMP / PKA pathway is involved, and the administration of cAMP analogs then accelerates the phase sequence. In addition, there is evidence that the cAMP / PKA pathway also plays a role at night. He seems to support the effects of the above glutamate and PACAP release in the early hours of the night and to counteract them in the late.

When night and night-active hamsters, the mechanism that is responsible for light-induced Phasenvorläufe, ie glutamate, Ca2 / calmodulin -dependent protein kinase and the neuronal NO synthase involves putting in turn ends up affecting the " clock genes ". This influence can be found again in the early and late hours of the night different place. In the late night hours, it leads to activation of the guanylyl cyclase cGMP-dependent protein kinase ( PKG cGMP -dependent protein kinase ), which in turn accelerates the phases. In the hamster, the levels of cGMP in the suprachiasmatic nucleus is the day the highest. The change seems to the cGMP - phosphodiesterase activity and not to be associated with the guanylyl cyclase. In light stimulation in the late night hours, the levels of cGMP increases significantly, but not at the same stimulation in the early hours of the night, from which it can be deduced that it leads to a phase of acceleration rather than a delay. cGMP-specific phosphodiesterase inhibitor to prevent the hydrolysis of cGMP, allow the enrichment of the substance in the cell. Sildenafil prevents the effect of the phosphodiesterase -5 and cGMP to the extended, thereby increasing the effect of the NO-Synthase/cGMP-Stoffwechselweges described above. The cGMP levels is of particular importance for the accelerated phase shift of the circadian clock.

Prevention and treatment

For the prevention and treatment of jet lag, there are a variety of behavioral recommendations that aim to facilitate the adaptation to the time zone of destination and so alleviate symptoms of jet lag. For short trips, however, can also be taken into consideration to maintain the day-night rhythm of the home against the encountered reality.

General behavior recommendations

The following behavioral recommendations are based in most cases on experience and are not supported by medical studies.

• Already in the aircraft clock switch to the time of the destination country to mentally get used to the new rhythm of time
• Join the daily rhythm of the destination
• Spend a lot of time at the destination outdoor
• Provide sufficient sleep the first night after arriving at your destination
• Avoid during the first two days after landing strenuous activities
• Neither are taking sleeping pills or alcohol

Influence of light

In analogy to the basics found in the animal model is based on laboratory studies, however, only a few field trials, announced that the time of exposure to bright light - relative to the phase of the lowest core body temperature (3 to 5 clock sense of time ) - a special impact on has to adapt to a time change. Has a bright light in the six hours before a, it delays the changeover, in the six hours after it encourages them. On a flight to the east up to nine time zones so the internal clock must be the goal, by light exposure in the six hours after the body temperature is at its minimum to adjust. At the same time such a light exposure should be previously avoided because it leads to a delay in the conversion. In hours converted it means that you (on the perceived time, not to the local time based ) suspend after 5 clock bright light and should avoid ago 3 clock. On all flights to the west and over nine time zones to the east, however, a delay in the conversion should be sought in that one exposes oneself in the six hours ago 3 clock bright light and it avoids the six hours after 5 clock. So if you are on a flight to the west there lives according to the usual habits of life analogous to the local time, which is in accordance with these rules, but not on a flight to the east. This concept explains the often described sensation that travel to the West are better tolerated than those to the east. As an aid to the implementation of this concept battery-powered " light goggles " and corresponding tables for travelers have been developed. These laws can also be used preventively.

Melatonin supplements

The frequently advocated use of melatonin preparations for the relief of jet lag remains controversial. Although a meta-analysis of several clinical studies showed evidence that melatonin may be effective at a dosage of 0.5-5 mg, another meta-analysis, the efficacy of melatonin in question, however, and also highlights the problem of possible drug interactions (eg. antithrombotic agents and antiepileptics ).

Drugs

The use of medication has to be adapted to the new daily rhythm. This is particularly relevant for some hormone preparations such as insulin or the mini pill. Before traveling between different time zones you should always consult with an appropriately retrained doctor or pharmacist travel medicine therefore.

Nutrition

An adequate fluid intake during the flight can help prevent dehydration and to improve the well -being after the flight, regardless of the jet lag syndrome. Whether a special diet actually has a positive effect on jet lag symptoms, will have to confirm further investigation; recent studies seem to confirm this influence, however.

Origin of the term

Historically, the worldwide spread of the term " jet lag " goes ( in the sense used today ) back to the work of Charles Ehret ( American Chronobiologist, 1923-2007 ). Through his 1983 published along with Lynne Waller book Overcoming Jet Lag, the term first came to the general public. The book was sold over 200,000 copies. It attracted attention at that time not only with musicians, athletes, business people, diplomats and shift workers, but also when U.S. President Ronald Reagan and the military.

Demonstrably, the term was, however, in the mid- sixties of the 20th century at the rainbow pages of the press. More or less it was ironic then called one of the chic new ailments or used as alliteration to jet set. Also in the Anglo-American literature, he appeared before 1983.