Jet lag is a temporary sleep disorder, very common among people who travel through different time zones in a short period of time. It is characterised by symptoms that are transient and usually decrease naturally.

However, as a consequence of the great mobility that characterizes our current societies, science has done a lot of research on its effects as well as some ways to remedy it. Below we explain what Jet Lag is (and why it is called that), how long it usually lasts, what the symptoms are and what remedies exist.

What is Jet Lag?

Jet lag is a temporary disorder of the Circadian rhythm of sleep (CRSDs), also known as jet lag, which often affects people who travel through different time zones at short notice.

It is known as Jet Lag, for the Anglo-Saxon terms plane and delay, which more or less could be translated into the expression: jet lag. This is because the most common case is precisely that of having made a trip by plane from one country to another, whose time difference is significant (from east to west, or vice versa).

However, Jet Lag can also occur by making car trips through the same time zone, but which modify our waking and resting times. For example, if a trip is made overnight.

Even some of your symptoms may occur without the need to travel, if our daily activities require us to significantly modify the times when we activate and fall asleep.

It is characterized by some symptoms related to physical and mental performance, for example, difficulty in sleeping (at the times that the destination is used to), which in turn causes much fatigue and tiredness, little energy especially during the day, and a feeling of being less alert or less attentive.

Generally, all these symptoms are transient, however, if the person has the need to make long trips constantly, jet lag can cause more severe sleep disorders, as well as some alterations in cognitive functions and even other health damages related to the gastrointestinal system, especially as the traveler’s age increases.

Main causes

As we have seen, the cause of Jet Lag is to have made a long-distance trip in a short time, which implies an important change in the schedule of wakefulness and rest.

The latter is due to the fact that our biological clock is exposed to a very drastic modification that cannot be quickly assimilated. Specifically, our circadian rhythms are affected, which are the changes that occur in our body according to the natural external cycles, for example, as light and darkness change.

Thus, Jet Lag results from strong changes in our body’s internal rhythms, as we are not used to sleeping in the day and night cycles of the destination. Although these are very drastic changes, the body can get used to them naturally over the course of a few days. In this process, there is a hormone that plays a very important role: melatonin.

Remedies and treatment

While our circadian rhythms are quite flexible, Jet Lag decreases on its own, without the need for specific treatment . It is estimated that for every hour of difference between the country of origin and the country of destination, the organism takes a whole day to recover, although this may vary according to each person’s body, as well as according to the specific route followed.

Our circadian rhythms are regulated by a gland located in the center of the brain of all vertebrates, which is responsible for organizing various physiological and neurological processes. This is the pineal gland.

This gland produces and secretes a hormone called melatonin, which plays a central role in regulating sleep patterns.

1. Functions and benefits of melatonin

Among other things, melatonin helps our organism to synchronize with the natural external cycles (light and dark), thus influencing the time it takes us to sleep and to stay awake or at rest.

Therefore, it has been a much researched substance recently. Some studies have found that melatonin helps to “reset” the biological clock , that is, it favours the synchronization of circadian rhythms with the time of the destination.

As a hormone whose production is inhibited by light, and is stimulated in the dark, melatonin intake has more effects when it is ingested at night. In fact, taking melatonin during the day may have the opposite effect (making it difficult again for circadian rhythms to synchronize with external natural cycles).

Melatonin has gained much popularity in recent times, so it can be found in tablet or capsule form, although there are many foods that encourage its natural production within the body, such as rice, oats, corn, tomatoes or bananas.

Recommendations for prevention

It is important to take the hours of rest that the body asks us for , even it can work to take a whole day of rest before starting with the tasks or activities we have planned.

On trips from west to east it is advisable to lengthen the days and avoid light in the mornings; unlike trips from east to west where it is preferable to avoid any light at night.

Bibliographic references:

  • Sack, R., Auckley, D., Auger, R., et. al. (2007). Circadian Rhythm Sleep Disorders: Part I, Basic Principles, Shift Work and Jet Lag Disorders. SLEEP, 30(11): 1460-1483.
  • Davidson, A.J., Sellix, M.T., Yamazaki, M., et al. Chronic jet-lag increases mortality in aged mice. Current Biology, 16(2): R914-R916.
  • Herxheimer, A. & Petrie, K. (2002). Melatonin for the prevention and treatment of jet lag. Cochrane Common Mental Disorders Group. DOI: 10.1002/14651858.CD001520
  • Petrie, J., Conaglen, L. & Thompson, Ch. (1989). Effect of melatonin on jet lag after long haul flights. The BJM, 298:705 doi: