Brief overview
- Symptoms: Fatigue, sleep problems, decreased performance/motivation, headaches, gastrointestinal problems.
- Causes and risk factors: Daylight and darkness control an internal clock via hormones. If it gets out of balance, jet lag symptoms occur.
- Treatment: No medical treatment necessary. Targeted measures can alleviate and shorten the symptoms.
- Diagnosis: By taking a medical history from the family doctor.
- Course and prognosis: The symptoms disappear on their own after a few days.
- Prevention: Start adapting to the new time zone even before the flight.
What is jet lag?
Jet lag is not a disease, but a temporary condition caused by the rapid crossing of time zones (shifts in the day-night rhythm). Due to the rapid time zone change, the traveler’s internal clock and the external time of the environment are temporarily out of sync.
When traveling at a slower speed, for example by car, bus, train or ship, the internal clock, on the other hand, manages to synchronize with the new time zone – the typical jet lag symptoms do not occur.
Two-thirds of people feel jet lag symptoms when they cross time zones by plane. The rest are spared or experience only mild problems.
How does jet lag manifest itself?
If you suffer from jet lag, it means you may experience the following symptoms:
- Disturbed general condition
- Fatigue
- Trouble falling asleep and staying asleep
- Increased need for sleep
- Increased fatigue
- Daytime sleepiness
- Lack of concentration
- Decreased performance
- Headaches
- Loss of appetite
- Gastrointestinal problems
- Dampened mood
- Decreased motivation
In addition, jet lag affects kidney function, the cardiovascular system, and cortisol and melatonin secretion, among other things.
Jet lag: flight direction
Jet lag symptoms are usually more severe the more time zones you cross (a maximum of twelve is possible) and the faster this happens. Basically, they occur both on westbound and eastbound flights – but they are usually stronger on eastbound trips.
Jet lag: individual differences
Not all people react equally sensitively to a rapid change of time zones. Jet lag symptoms therefore vary greatly from person to person. Jet lag is therefore of varying severity for different travelers. In general, jet lag seems to be more pronounced in women and older people, while men and younger people usually synchronize more quickly with the new time zone.
In addition, evening people and people who change their daily rhythms often adapt to a new time zone more easily than typical morning people and people with fixed sleep-wake rhythms.
What causes jet lag?
There is an internal clock ticking in every human being. It determines whether you feel awake or tired and how much you are able to do. It regulates hormone and electrolyte balance and body temperature, for example. The control center for the internal clock is a specific brain region. It is calibrated by the alternation of daylight and darkness. If this internal clock becomes unbalanced, jet lag symptoms may occur.
How is jet lag treated?
Jet lag and melatonin
A supposedly effective drug against jet lag is melatonin. The body produces this hormone naturally: Darkness promotes its release; if daylight falls on the retina, this inhibits melatonin production.
Melatonin tablets may therefore normalize the disturbed day-night rhythm during jet lag. The danger here is that taking the tablets at the wrong time prolongs the symptoms.
The correct time to take melatonin tablets is particularly difficult to assess for flight crews. It is often unclear to them which time zone their internal clock is actually ticking. Another disadvantage of melatonin tablets: Little is yet known about possible long-term and side effects and what happens if you take them regularly.
How is jet lag detected?
Those who suffer severely from possible jet lag symptoms have the opportunity to seek advice from their family doctor. The patient’s information about his or her symptoms and recent travels is usually enough for the doctor to diagnose jet lag. Possible questions in the anamnesis conversation are:
- What are your symptoms?
- How long have you had the symptoms?
What is the prognosis for jet lag?
Jet lag symptoms disappear on their own after a few days – once the internal clock has synchronized with the new local time. This is usually faster for flights to the west than for flights to the east.
As a rule of thumb, people need an average of one day per time zone they fly through to get used to the new local time and recover from jet lag.
Different bodily functions adapt at different rates. People get used to the new sleep-wake rhythm more quickly, while hormone levels take a little longer to fully adjust. This is the case, for example, with cortisol, which ensures that you are able to perform at full capacity when you are under high stress.
Tips against jet lag
With the following tricks, you can help your body get used to a new time zone more quickly. In this way, you can prevent jet lag or alleviate or shorten the discomfort.
But be careful: this only makes sense if you stay in the new time zone for more than two days. For shorter trips, it is advisable not to allow your body to adjust at all.
- Start adjusting to your future time zone three days before you fly. If you’re flying west, go to bed one hour later and get up one hour later on each of those days. If traveling east, it works the other way around: go to bed one hour earlier and get up one hour earlier each day. Additionally, it helps if you shift your meals and your activity-rest cycle right along with them.
- Set your clock to the time of your destination as soon as the plane takes to the air.
- Sleeping on the plane? If you’re flying east, try to sleep during the trip. If you are traveling west, try to stay awake and sleep only when the sun sets in the destination country.
- Adopt the rhythm of the new time zone directly, so eat at the usual local times, use daylight for physical and mental activities, and go to bed according to the new day-night rhythm.
- Additionally, it may help you to take the first few days in the new place slowly – if that’s possible – and get extra sleep the first night after arrival.
Further examinations are generally not necessary in the case of jet lag. However, if one would like to record the type and severity of the difficulties in falling asleep and sleeping through the night more precisely, a sleep log is created.
For this purpose, it is necessary for the affected person to document important sleep parameters every day over a longer period of time, for example the time when he or she goes to bed and the time when he or she gets up in the morning, how long it takes to fall asleep, whether he or she wakes up during the night, and so on. The doctor then evaluates the data.
