The jet lag (sometimes called dysrhythmia) is a form of disorientation and fatigue caused by an abrupt transition to a different sleep / wake time of several hours. It is caused by a quick trip through the Time Zones.
Causes and severity of jet lag
Some people suffer from it more than others, but in general jet lag tends to occur when two or more time zones are crossed on a single flight. The term itself reflects the origin of the phenomenon, since it is composed of jet - English for "jet plane", the most common means used in today's commercial aviation - e lag - delay, slowdown, time lag.
The phenomenon is caused by a series of factors, for the most part attributable to the fact that our biological clock (which regulates for example the cycles of sleep and wakefulness and the sensation of appetite) is not aligned with the local time. The most obvious symptom is sleep disturbance: for example, traveling east we tend to be sleepless in the evening and cataleptic in the morning; in some cases, especially when we have landed for at least a day and therefore the adjustment process has begun, sudden falls asleep can occur even at times that do not coincide with either the local night or the night in the country of origin. Another fairly common symptom is a lack of appetite at mealtimes (and, conversely, a feeling of hunger at unusual times). Side effects include bad mood, digestive disturbances, temporary and mild weakening of the immune system.
Understanding the causes of jet lag can help treat its symptoms. In the first 12 hours, the most problematic element is the absence (or unwanted presence) of sleep, for the simple fact that you overslept (or didn't sleep a wink) on the plane. This is not really a symptom of jet lag, in the sense that you can easily replicate the lack of sleep even at home by staying up all night and then making an effort, during the next day, not to fall asleep until the evening. The real jet lag is linked to some physiological functions that our body performs regularly during the day, in particular the production of melatonin. Melatonin is a hormone that regulates sleep and wakefulness: when it is produced and begins to circulate, we fall asleep. It is produced on the basis of exposure to sunlight (which stops its production and destroys the one in circulation), so that when it becomes day it is natural for us to wake up. Our body, however, also regulates the production of melatonin on a daily cyclic basis. For example, someone who had just arrived in London from New York would have a hard time falling asleep in the evening, because according to the biological clock, melatonin production shouldn't start for at least another five hours (the time difference between origin and destination). Similarly, those traveling west will be able to stay awake with relative ease at least until sunset, but will have heavy sleepiness as soon as it gets dark. Appetite is linked to the sleep cycle and is therefore affected by it; in turn, both sleep disturbances and lack of appetite (and therefore inadequate nutrition) can cause all the other effects already mentioned.
As mentioned, jet lag is also exacerbated by the fact that long hours spent on a plane can lead to sleeping too much, or not enough, or perhaps at the wrong time of day with respect to the time of destination. The fatigue of traveling plus the misalignment with local time can lead to falling asleep right after lunch, or being fully awake in the middle of the night.
The relationship between the number of time zones crossed and the severity of jet lag is not necessarily intuitive. Often a difference of 4-5 hours (which causes you to wake up at 2 am) can be more annoying and take longer to overcome than a complete reversal of day and night (i.e. 12 hours).
For locations near the date line (International Date Line or IDL), a time difference of 23 hours (for example, Hawaii and New Zealand), jet lag is contained, because at the biological cycle level it only detects what time it is, not what day it is; a difference of 23 hours is equivalent to a difference of 1 hour.
It is not the length of the flight that matters but only the time difference between the place of departure and the place of arrival. Flying by Paris to Johannesburg, it could take 15-20 hours but you wouldn't experience any jet lag as there is only an hour difference. One flight from New York to Tokyo, on the other hand, it involves a difference of 13 hours, and thus the sleep-wake cycle is effectively reversed.
Flights from east to west, where they earn a couple of hours, are usually a little easier to manage, as most people find it easier to stay up a little longer and then go to bed later. a little earlier. Obviously, the greater the time difference, the harder it will be to stay awake.
What strongly influences the ease of adapting to the new time zone is the time of departure and arrival of the flight: as mentioned, for many it is relatively easy to stay awake longer, accumulate a few hours of late sleep for when you have to fall asleep. in the evening, so for trips to the east it will be preferable to arrive in the morning rather than late in the evening (otherwise you will find yourself lying in bed sleepless). This, however, is a recommendation that depends heavily on personal preferences, in particular on how to "use" the time spent on the plane (v. Prepare for crossing time zones).
Prepare for crossing time zones
Some airlines are bringing Boeing's new model, the B787 Dreamliner, into service. This aircraft has advanced features capable of reducing the effects of jet lag, including an enhanced air filtration system as well as ambient lighting designed specifically to recreate a nocturnal atmosphere. It may be useful to choose flights operated by a 787.
You can't completely avoid jet lag, but you can make things easier to mitigate its effects. It is important to start using your destination time right away: just after boarding, set your clock and avoid thinking about "what time would it be at home". If you arrive in the morning, try to sleep as much as possible on the plane; vice versa if you arrive in the (late) afternoon try to stay awake for the whole flight. On longer flights, more precise and determined people will also be able to sleep for a few hours until morning at their destination and then stay awake or - depending on the direction of travel and arrival time - stay awake until evening at their destination and then fall asleep.
Traveling west it is likely that you will wake up in the middle of the night. The best strategy is to force yourself to stay in bed with the light off and your eyes closed: even if you can't go back to sleep and although this type of rest is not "real" sleep will still help you during the day. If you really can't sleep, try planning activities for the first morning by taking advantage of the fact that you are already up. For example, coming from America you can visit the Tsukiji fish market to Tokyo and have a sushi breakfast, or hike up Diamond Head at Hawaii to see the sunrise, while coming from theEurope you can enjoy the sunrise somewhere in the Rocky Mountains.
New scientific research suggests that fasting (not eating) can help overcome jet lag by resetting the body's circadian rhythm (biological clock). Not eating 24 hours or more before arriving at your destination helps you feel less tired once you arrive. Earth's light / dark cycles affect our circadian rhythms, but so do our consumption patterns. Resetting our feeding cycles can reduce the effects of jet lag. If fasting isn't your thing, still strive to eat at the correct times and eat lightly to avoid adding indigestion to the general malaise of jet lag. Airlines usually try to match the time of meals served in flight with the "normal" time you would eat at your destination. Contain - better: avoid - the consumption of alcohol during the flight. Alcoholic beverages dehydrate quickly and this, coupled with the fact that the body dehydrates much faster on the plane than on the ground, results in an overall unhealthy effect. Plus, alcohol-induced sleepiness doesn't help prevent jet lag, nor does fainting from a blow to the head! Hydrating properly with soft drinks does not eliminate the problem of jet lag, but it does reduce other hassles of air travel that often contribute to the general feeling of lightheadedness after a long flight. Drinks rich in caffeine should be taken at the right time and only if you want to stay awake.
You can help the process of adapting to the new time zone by working on it early, for example by gradually bringing the hours of sleep and wakefulness closer. Some even advise, if given the possibility, to start adjusting to an intermediate time zone one or two days in advance (going to sleep and waking up three hours earlier or later than usual, depending on the direction of travel).
Medicines and supplements
There are many sleeping pills and other drugs on the market that are used to reduce the main effect of jet lag, which is sleepiness during the day and the inability to fall asleep in the evening. Some use drugs containing sedative-hypnotic active ingredients such as zolpidem, zopiclone, zaleplon to induce sleep at bedtime, while others rely on anxiolytic drugs such as diazepam or alprazolam which also have a calming effect; finally there are those who rely on the side effects of an antihistamine to fall asleep. For those who prefer to focus on staying awake at the right times, there are stimulant medications such as those containing modafinil that help keep you awake and alert (they are also used by those in a night shift profession). However, it should be borne in mind that all the drugs listed above have important side effects and in some cases can induce addiction or withdrawal phenomena: it is always advisable to evaluate the advantages, risks and alternative options with your doctor before taking drugs.
Less radical solutions than taking sleeping pills and stimulants include herbal supplements and preparations.
The easiest supplement to take to combat jet lag is probably melatonin itself, which is available in 1 or 2 mg pills and can be purchased at the pharmacy. It is best to start taking it between one and three days before leaving, at bedtime, also to understand what the ideal dose is (which can vary between 1 and 3 mg depending on body weight, metabolism and many other factors) . Another mild sleeping pill with limited side effects is valerian extract.
Other supplements include both solutions marketed by well-known pharmaceutical companies and packaged preparations by individual pharmacies. Among these, some also integrate sleep induction ingredients that strengthen the immune system and soothe digestive disorders. The latter can also be faced with lactic ferments, especially in the case of travel to tropical countries, where high temperatures can compromise the integrity of the intestinal flora.
Recovery from jet lag
The jet lag recovery it is a process that takes time. A general rule of thumb is that you can recover about 1 hour a day. You may notice improvements during your stay even after just a couple of days, but in the case of a short trip you will have more difficulty regulating yourself when you return: at that point your biological clock will be really confused and it will take a while to get back to full normal.
Try to follow the activities of a normal day in terms of the time zone you are flying in. If you land at 7:00 am, for example, you have probably been served breakfast on the plane, so go to your accommodation, drop off your luggage, take a shower (if the hotel offers you a room in the morning) and go to see some of the local attractions, making sure to stay in natural light and outdoors. As mentioned, it is sunlight that controls the production of melatonin, so it is essential to stay outdoors as much as possible: it is particularly difficult to stay awake if you remain indoors exposed to artificial light all day (museums, offices, halls meetings ...). And if you find yourself indoors and sitting when "at home" it is getting evening, you will suffer from real falling asleep (needless to say that giving in to sleepiness and taking a nap will only complicate your adaptation). The first day it is useful, regardless of the direction of travel, to accumulate a few hours of overdue sleep in order to arrive tired in the evening, have dinner and lie down so that you can enjoy a good night's sleep. Adopting timetables from active people from the first day (e.g. waking up early if traveling east) will help you set the pace and better adapt to the time zone.
See also
Travel by plane
