What is it?

Travel is an amazing activity one can take up to explore beyond the horizons of their knowledge. However, there are two sides to everything, both good and…not so good. Jet lag is one of the major drawbacks when one travels past multiple time zones (five or more) by plane. It is a physiological condition that affects the human body when the circadian rhythm, or the body’s internal clock, desynchronises from the time zone it finds itself in. When this happens, one would find themselves experiencing fatigue, sleep disturbance, headaches, indigestion, etc. In simpler terms, the body is normally used to functioning according to an invisible 24-hour clock that physically responds to certain environmental factors. But when these factors change and turn different to what the body is accustomed to, it causes jet lag.

The discovery

The first description of the symptoms of jet lag arose in 1931, from the book Around the World in Eight Days, which was co-authored by aviator Wiley Post. However, the Federal Aviation Administration did not see the connection between the symptoms and the disruption of the body’s circadian rhythm until a study conducted in 1969. Before that, the symptoms were considered to be the collective result of travel fatigue. Jet lag gained attention with the introduction and rise in entrainment (synchronisation of one’s biological clock to an environmental cycle) research. The term ‘jet lag’ was created based on the experiences of people who travel at high speeds across various time zones on a jet-like mode of transport. The body quite literally lags or falls behind the cycle of the time zone. The term was first used in an article by Horace Sutton, written in the Los Angeles Times in 1966. 

What causes it? 

So what exactly are the main causes for the body experiencing jet lag? It is just an intangible time difference. How can that affect the body so strongly and create a wide array of symptoms? Well, the answer to that lies in a few things. For one, the environment. Time may be intangible, but the physical connection between our bodies and the environment is what must be focused on. For example, there is the light-and-dark cycle. This is how the body synchronises its functions to the Earth’s day-and-night rotation. The sunlight detected by the retinal ganglion cells present in the eyes sends signals to the brain that affect body temperature, melatonin secretion (melatonin is a sleep hormone that is secreted in response to dim light or darkness), etc. Another main cause for jet lag is the disruption that occurs in the suprachiasmatic nucleus (SCN), a region in the brain that is located in the hypothalamus and is mainly responsible for the sleep cycles in organisms. The time taken to adjust to different time zones differs from person to person. The more time zones that are crossed within a low amount of time, the higher the risk factor of jet lag. One would be both mentally and physically affected by the alteration of the time zone, which is further emphasised by the symptoms of anxiety, irritation, fatigue, insomnia, headaches, reduced appetite, etc. 

Small solutions

The effects of jet lag can be prevented or at least reduced if proper steps are taken. For example, slowly and gradually shift your sleeping schedule three to four days before you are to head to the airport. Advance your normal bedtime by one hour if you are planning to travel east, and in case you are going west, try and go to sleep one hour later than normal. While you are on the flight, slowly change the timing of basic tasks like eating to match that of the destination’s time zone. Ensure that you are properly hydrated and take short naps. Once the flight lands at the destination, the first thing to ensure is that your body receives light exposure. Morning light in the case of eastward travel, and late afternoon light if it is a destination from westward travel.