Causes
The symptoms of jet lag can vary considerably from person to person, both in their nature and in their severity. In addition, the time differences between the point of departure and arrival also play a decisive role. Pronounced fatigue, which only diminishes to a limited extent even after days, is one of the best-known symptoms of jetlag.
As a rule, affected persons report pronounced fatigue, which can last up to five days after landing. Even short periods of sleep during the day are usually unable to dispel the tiredness typical of jetlag. Furthermore, this fatigue is paradoxically often accompanied by severe sleep disorders.
This means that affected persons are unable to fall asleep at night despite persistent fatigue. In addition, jetlag at night often leads to an unscheduled awakening of the affected person. The reason for this phenomenon is the fact that the organism is still adjusted to daylight during the night.
Only after several nights is it possible to sleep through the night again. From this point on, jet lag-related fatigue typically decreases significantly. Another frequent symptom of jetlag is pronounced dizziness.
This symptom, too, usually disappears completely several days after landing. Since the time change also affects the gastrointestinal tract, loss of appetite, constipation or diarrhea can also occur. Sometimes the affected persons also suffer from pronounced mood swings. It is not yet clear whether the typical depressive moods are caused directly by the time change or rather by the other jet lag symptoms.
Duration of a jet lag
How long a jet lag lasts varies from person to person. For one thing, it seems to depend on age. Often it is more difficult for older people to adapt to a time change than for young adults.
Furthermore, the direction of flight plays a decisive role. A journey to the west and an apparent extension of the day can usually be better compensated by the body than the other way around. This is probably due to the fact that the natural human biorhythm is somewhat longer than 24 hours.
It is said that the body needs about one day per time zone to adjust. Further flights therefore result in a longer jet lag than short flights with only two hours time difference. The individual organ systems can also take different lengths of time to adapt. Thus it can be that the eating habits have already become accustomed to the new time, sleep disturbances however still some days longer exist.