Overcoming Jet Lag: Alternative Models - Seminar, April 27, 2000

Helmut Müller-Ortstein, MD, Centrum für Reisemedizin

DR. DIMBERG: Thank you very much, Mark. That was comprehensive.

Now we have Dr. Helmut Muller-Ortstein who will give a presentation. And Dr. Muller-Ortstein is a general practitioner, occupational physician and specialist in psychiatry and neurology. He has been a ship doctor and has worked for Lufthansa. He has published several books on flight anxiety and fitness for air travel, and he will make a presentation on business prophylactics for business travelers.

Please.

DR. MÜLLER-ORTSTEIN: For myself, I am a member of the Travel Medicine Institute in Dusseldorf and Berlin, and we give some lectures in travel medicine, one side for medical doctors and we give lectures for business travelers.

For example, we have themes like LTD on mountain sickness or vaccination or like jet lag, for example, for the business traveler. And I speak now to you what we give on content on important points for the non-doctors for business travelers.

I'll give you some facts.. The biological rudiments of the human body are controlled by internal clocks. These endogenous rhythms, however, need to be synchronized by external stimuli with a 24-hour day. This synchronization is performed by signals called sight gables or pacemakers such as bright light and social contact.

If the sight gables are not present or are too weak, there is a danger that optimum phase adjustment cannot be sustained. This condition brought about by circumstances in everyday life can be observed in shift and night workers as well as in air passengers after long-haul flights.

It is also possible, however, for problems in the adjustment of biological rhythms and subsequent impairment of performance to occur without any identifiable external cause.

The first slide: Normal circadian rhythms include the hormonal rudiments of cortisol and melatonin, body temperature and sleep weight patterns. The synchronization of these endogenous rhythms with the external day/night rhythm through the action of melatonin. If this connection fails, the circadian rhythm still continues to manifest somehow, but they are no longer synchronized. Instead, they run freely and independently of each other.

This process of uncovering or resynchronization occurs in long-haul flights which pass through more than three time zones. The main results are sleep disturbance, impairment of psychological performance and wide variety of effects of well-being, known collectively as jet lag.

Jet lag manifests itself in many different ways. For myself, I will see people with reduced cognition. They have reduced vigilance.

Experience has shown that crossing time zones in a westerly direction, which has the effect of lengthening the day and prolonging the period of light, is generally easier to cope with because normal circadian rhythm in the majority of people is 25 to 26 hours, longer than the normal 24-hour days. There is generally always a time lag when a person's internal clock is set to a new time.

The changes are much more pronounced, following an eastbound flight, and typical symptoms include tiredness during the day and reduced performance. When crossing time zones of over eight hours on an eastbound flight, a person's internal clock can adjust backwards where the day is perceived as being shorter or forward where the time difference is correspondingly greater, depending on the individual.

There are often considerable variations in the speed at which different people's internal clocks readapt to exogenous sight gables at different destinations.

The average readjustment time for the sleep/wake rhythm in two to three days is considerable shorter than the readjustment time for body temperature five days or cortisol concentration eight days. Experiments have shown that older people tend to have greater adjustment problems and more pronounced symptoms of jet lag on long-haul trips than younger people.

The flattening out of the circadian rhythm of melatonin in old age is very well documented and could be one of the factors responsible for increased sleep disturbance at night and daytime fatigue in the elderly.

A key role in the synchronization of the external day and internal biological clock is played by the production of melatonin regulated by the suprachiasma nucleus SCN, an area in the hypothalamus.

There have also been increasing indications recently that various parameters of different body functions that were once sought to be mutually independent, in fact, interact with each other and regulate each other both up and down. There are also many questions still to be answered in the field of psycho-neural endocrinology. While there is still much that is not known or understood, it is clear that hormonal and immunological reactions and the reactions of the neural transmitters are clearly related to each other to and hence to performance.

Progress has also been made in identifying the genes in various spaces which are responsible for the way the internal clock operates. In the modern world, normal circadian rhythms are constantly being disturbed by such factors as shift work, night work, work in different global locations and also the process of crossing time zones in airplanes.

Gradually, those two points are becoming the focus of attention in professional aviators and in business people who fly great distances. Such people often exhibit a combination of disturbance factors.

For business people to be able to adapt to useful strategies to counteract jet lag, they need to understand the nature of the phenomenon and to appreciate the fact that jet lag can manifest itself in a variety of forms. They must also be made aware of the fact that jet lag can only be minimized, not prevented.

It is important to note that problems generally disappear after three to seven days in the case of westbound flights and after five to fourteen days in eastbound flights. Problems with psychological and mental performance may last a day or two longer.

However short of time one may be, it is important to give one's internal clock the opportunity to adapt to the new time and to the new environmental signals. Former American President Eisenhower had the right idea. He would always take the wise precaution when traveling abroad of arriving at his destination a few days ahead, ready to start talks only after having allowed himself a suitable time to adjust to the new time zone.

An alternative strategy is to adjust the internal clock before leaving home by shifting the time of various daytime activities to coincide with local time at one's destination. Some people find success in adjusting to the new time by going and getting up earlier for a few days prior to departure in order to gradually shift their sleep pattern.

However, the maximum shift of using this method is likely to be three hours. The disadvantage is the disruption to one's routine at home. The method is costly, requires careful planning and is difficult to integrate into one's daily life. Sportsmen and women are known to have had success with this approach.

When flying westbound, it is a good idea to take naps; for eastbound, most night flights, passengers are asked to try to sleep on the aircraft. Whatever the case, appropriate sleep management is important.

On reaching one's destination, it is important to keep strictly to local time, have increased social contact, take physical exercise and spend as much time as possible in the fresh air. Bright light is one of the most important sight gables for the internal clock. It is also important to bear in mind, however, that light can put back or bring forward the body's own rhythm within a period of twenty-four hours.

Business travelers should, therefore, study take-off times, flight duration, time zone difference and the scheduling of business meetings carefully in order to be able to plan accordingly. It may also be an advantage to fly on business trips in the right direction.

When flying eastward to Europe from the USA, for example, an American business traveler, providing he has had enough sleep onboard, is likely to be more awake than his European colleague in the evening of the first day after his arrival, since most of the circadian rhythm is connected with performance demonstrates their peak afternoon, the acroface, and the period of least activity in the early hours of the morning.

In this scenario, the American should not be at a disadvantage around the negotiation table with the European counterpart. The matter should be after an eastbound flight, get down to business as quickly to possible when the time is right for the body and before desynchronization manifests itself.

Then, it is advisable to have a break from negotiations for a few days. When flying westbound from Europe to American, for example, it is unwise for a businessman to allow himself to be persuaded to start business within two to three hours upon arrival, since this could work to one's disadvantage.

The amount of time a traveler needs to wait after a westbound flight until the time is most advantageous for business is considerably however. The biological clock normally adjusts to local conditions more quickly in this direction.

Benzodiazopines which are often mentioned as fast action remedies for jet lag add only to improve sleep requirements. A symptomatic therapy of jet lag symptoms with a short acting benzo, for example, like triatsolam may be tolerated.

The downside is that they can induce a hangover, sensitivity to sleep; it also varies from person to person. Melatonin is not yet officially approved in Germany; for short stays or frequent long-haul fight travelers are recommended to stay on their home time.

Whether a man or a woman, you must look before a flight, no stress during the flight, no alcohol, drink a lot of water during the flight, eat little; after the flight, bright light, social contacts and activities. And for us flight-smart, we can say study the route, take-off times, flight duration, time zone duration; scheduled and non-stop flight, follow the safety demonstration, do not drink alcohol, eat little, check out the aircraft, and choose reputable airlines.

Thank you very much.

Disclaimer: These Proceedings have been produced from transcripts made from audio tapes. Efforts were made to check the accuracy of information with the various authors, but this accuracy is not guaranteed. If there is information that you believe requires correction, please send a message to our e-mail address.