Causes of Jet Lag


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A condition that many travellers will have to contend with at some point, jet lag can cause tiredness, sleeplessness, and irritation over the first few days of your trip away. In this article we look at what causes jet lag.

Jet lag is product of modern travel, and the condition derives its name from airplane travel, the only means of travel quick enough to expose our body to the environmental changes underpinning jet lag.

The condition is caused by travel across different time zones, an action which exposes our light sensitive biological clock to abnormal amounts of sunlight. The result of this is a disruption of key hormone levels responsible for regulating our bodily functions and entraining them to a 24 hour day-night cycle.

This hormonal rhythm is vital to a number of bodily processes, and informs your body with regards to when it should eat, sleep, and so on. The period during which you are out of synch with the time at your target destination is jet lag.

Jet lag is strongly influenced by how far you travel and in which direction. As has already been mentioned, you need to cross time zones to experience jet lag. Typically crossing fewer than three time zones will not cause jet lag as you will only be out of synch by a couple of hours, and can quickly adjust without any major physiological effects.

Crossing more than three time zones will cause jet lag, and the more time zones you cross, and hence the further out of synch you are, the more severe and long lasting the jet lag will be. That being said even severe jet lag will clear in a few days once your body has adjusted to the change.

Direction of travel is also an important factor in causing jet lag. Travelling north to south or south to north will usually not cause jet lag, regardless of the length of the flight. In order to cause jet lag you will need to travel either west to east or east to west. This directionality can influence your symptoms as well, with people travelling from west to east often experiencing difficulty staying asleep and abnormally early waking times. Conversely people traveling in the opposite direction will have trouble getting to sleep.

Jet lag is very much a condition that is a product of modern travel habits. Unfortunately while we can travel halfway across the world with relative ease, our bodies can sometimes struggle to keep up with the transition. The cause of jet lag, as discussed in this article, is travel across time zones and the resulting effect this can have on our physiology.


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