Jet lag is a physiological condition caused by disturbance to the body’s natural circadian rhythm, or internal clock. This condition is largely caused by air travel across one or more time zones, from which its name is derived, but can also be caused by shift work or other factors.
The effects or symptoms of jet lag generally last only a few days, but could last longer depending on the amount of disturbance the steps taken to combat them.
Circadian rhythm refers to the natural tendency of all living things, be it human, plant or animal to operate on a 24 hour cycle, and that cycle is further based on and influenced by the cycles of sunlight and darkness. When either of these cycles are dramatically changed, the lifeform can experience adverse and conflicting biological and brain wave activity as it attempts to cope to the new cycle. This can lead to feelings of fatigue, irritability and disorientation.
Jet lag can affect people of all age groups and both sexes. There are conflicting reports as to who is affected more by jet lag, younger or older. Some studies have indicated younger people can more easily handle the changes in circadian rhythm due to them being less ingrained in the body, while other studies show the complete opposite, that because younger people have less ingrained circadian rhythms they are likely to suffer more from the fluctuations. All studies agree that women are at a higher risk than men though, as estrogen is subject to jet lag like conditions.
As mentioned, travel across multiple time zones is the leading cause of jet lag. Contrary to a widely popular belief that it is simply the act of flying that causes jet lag, it is in fact the upsetting of the body’s rhythm by the newly introduced cycles of daylight, darkness, eating and other functions contrary to what the body is used to. As such, people on long flights in the same time zone (north to south for example) are much less susceptible to jet lag as are those on shorter flights that cross time zones. West to east travel is considered the more adverse than vice versa, as it pushes the cycles forward rather than back, which are easier to adjust to. Jet lag can be further induced by travel to areas of extreme darkness or sunlight in contrast to your natural environment, such as travelling to the extreme northern or southern regions of the world.
Nearly 93% of all travellers will experience jet lag at some point. It is generally accepted the body will take one day per time zone crossed to fully recover and adjust to the changes. This can vary, sometimes drastically, between individuals though, as some people can suffer severe, debilitating jet lag, while others are hardly affected by it. Jet lag can be further aggravated by other factors. Many people experience feelings of anxiety or nervousness when travelling by plane, and this can worsen jet lag. The dry air inside airplanes can also by hard on people used to humid environments, and may cause headaches and sore throats. Maintaining proper hydration during travel is important, so drinking water is advised. Of course, drinking alcohol either just before or during the flight is not wise. Alcohol will have a much stronger effect on you while flying, and will contribute to some of the other conditions that you are likely to experience.
Symptoms of jet lag are most fatigue and disorientation. Further symptoms may include loss of appetite, insomnia, mild depression, headaches and nausea. Disorientation is also contributed to by the travel to exotic locations, with various customs, foods, air quality, smells and so forth, and is otherwise known as culture shock.
The best method of combating jet lag is to plan ahead of your travel time by slowly adjusting your schedule to incorporate what will be your temporary new routine. This slow adjustment is not at all hard on the system, and will nearly eliminate the major effects of jet lag caused by circadian disruption, though jet lag may still be experienced due to other factors.
Shift work is the other leading cause of jet lag, and it potentially much more dangerous, as it is more likely to occur frequently and continuously over an extended period of time, usually many years. Some studies have shown drastically increased rates of heart disease in people with long histories of shift work. Shift work between day and afternoon shifts, while a change in schedule does not affect sleeping patterns, and is not nearly as hard on the body as shift work that alternates between day or afternoon and night shifts, or all three. There is very little that can be done to help the body through this process of constantly changing sleeping schedules, and it is recommended to avoid this type of shift work entirely if at all possible.
Reviewed September, 2007