There are several ways and methods of accelerating the resynchronization of the interior clock. Examples for this are the use of bright light or that of the neuro-hormon melatonin and/or melatoninagonists.The application of light and of melatonin has been tested several years ago already. Now, a melatoninagonist was tested in the Arbeitsmedizinischen Simulationsanlage (medical simulation facility)AMSAN
BRIGHT LIGHT: A COUNTERMEASURE FOR JET-LAG?
Abstract
After time zone flights, the environmental time is shifted abruptly. The sleep-wake cycle and the circadian system cannot follow this sudden phase shift. Therefore, some or several days are necessary to achieve complete adjustment to a new time zone. The effects resulting from the displacement between internal and external time are well known as jet-lag. In principle, timed bright light is able to enhance the resynchronzation process of the circadian system after advance or delay shifts. In this report, the effects of bright light exposure on circadian phases and amplitudes after real or simulated time zone transitions are reviewed from the accessible literature and are critically dicussed. It can be concluded that laboratory studies have not been unequivocally successful to support the hypothesis that bright light alleviates jet-lag. The sparse number of field studies do not yet allow a clear judgment on the beneficial effect of bright light treatment on jet-lag.
Essential Reading [1] A. Samel, H.M. Wegmann, Bright light. A countermeasure for jet-lag?, Chronobiology International 14, 173 - 183, 1997. Click here for further reading on the topic of jet-lag.
Melatonin
The human interior clock, the nucleus suprachiasmaticus (SCN), programs a day of 25 hours for us. Due to the external day of 24 hours, the interior period is shortened to 24 hours. There are different external "timers", the most important of which is light. The activity of the pineal gland is regulated by the SCN. With young people, the pineal gland produces a lot of melatonin by night, while there is almost no secretion of melatonin by day. Melatonin has the ability of influencing the activity of the SCN and of inducting sleep. The sleeplessness of many elderly persons is due to a lack in melatonin production. As melatonin is able to alter the interior clock and to induce "natural" sleep, it is used increasingly against jet-lag - although the use of melatonin in cases of jet-lag is not authorized in Germany. Because of this, many travelers procure melatonin e.g. in a supermarket in the USA and use it e.g. in single doses of 0.2 mg before the planned sleep.Melatonin is involved with a high number of mechanisms of reactions of the circadian rhythm. As it is also a potent catcher of radicals, some researchers also claim for it to have a restraining effect on aging and on the formation of cancer. Finally, individual tests on animals showed an influence of electromagnetic fields on the melatonin rhythm. Although all these additional effects of melatonin are not yet confirmed, melatonin has drawn a lot of attention in the last years.Since melatonin has a rather short half-life and is processed very differently from the intestine after oral application, several manifacturers are currently testing analogues for melatonin that are better directable for the treatment of jet-lag and for the induction of sleep. Because of this, several new medicaments will probably hit the market as melatonin replacements. Thus, a generation of medicaments will for the first time be developed for an original area of flight medicine (for jet-lag).
Essential Reading [1] A. Samel, Melatonin and Jet-Lag, European Journal of Medical Research 4, 385 - 388, 1999. Click here for further reading on the topic of jet-lag.