Captain Lim Khoy Hing explains what causes jet lag and how we can reduce its effects.
Words: Captain Lim Khoy Hing
A frequent flyer once asked: “Do pilots and cabin crew have special abilities that help them cope with jet lag?” The answer is no. Pilots and cabin crew suffer just as much. Any traveller that crosses more than four time zones can expect to feel some effects of jet lag. However, if you know how to manage it, you can lessen its effect.
WHAT ARE TIME ZONES?
Before clocks were invented, time keeping was done by the use of the sun’s shadow or with a water clock, an ancient device that measured time by the gradual flow of water.
Many early towns observed time based on sunsets and sunrises but this system was flawed. Dawn and dusk occurred at different times in different locations and the use of solar time became too unreliable to be of any use for the standardisation of time.
Time zones were not well set up and as such, the early American railroads maintained more than 300 time zones according to the sun’s position, making it difficult to coordinate time schedules. But this stopped when time zones were properly established. Since then, air travel has also adopted these time zones in order to have a uniform air schedule for departures and arrivals worldwide.
THE START OF TIME ZONES
Greenwich, a town east of London in the UK, is used as the reference for the computation of the starting point of the time zones. Greenwich Mean Time (GMT) starts at 0.
Given that there are 24 hours in a day and 360 degrees of longitude around the earth, it is obvious that each of the world’s one-hour time zones have to be 15 degrees or 900 nautical miles wide on average.
In reality, this is not so. In Malaysia for example, although the distance between Kuala Lumpur and Tawau is more than 15 degrees in longitude and spans more than 1,000 nautical miles, the country has only one time zone (+8:00 GMT) for convenience of standardisation. Similarly, India (+5:30 GMT) and China (+8:00 GMT) both have great distances from east to west, but have only one time zone unlike other expansive countries like the US, Russia and Australia.
Now that we understand time zones, let’s see how it affects pilots’ (or your) fatigue and jet lag. Pilots are not superhuman; jet lag affects them just as much as the average air traveller. This is why there are regulations in place to lessen the effects on pilots on duty.
For instance, if pilots have to fly through many time zones, they are restricted to a shorter working period or an increasingly longer rest period to ensure they are sufficiently rested before flying.
CAUSES OF JET LAG
A tiny organ in the brain known as the pineal gland triggers your circadian system (body clock) when you travel at great speeds over many time zones.
When light conditions are dim, the eye cells send a message to this gland, which releases a sleep inducing hormone called melatonin, in response to the darkness. As you are crossing many time zones during your flight, there is an imbalance in your body’s circadian system.
At your destination, your circadian system is not in tune with the new location, as daylight and darkness take place at times that your body is not used to. Jet lag is the result of your body catching up and resuming its circadian system.
COMMON SYMPTOMS
Jet lag manifests through headaches, irritable behaviour, poor concentration and a whole lot of sleep issues like poor and disrupted sleep upon arrival. This becomes worse if the traveller flies from west to east or away from the sun. Travelling from east to west or to an earlier time zone will result in fewer jet lag symptoms.
OVERCOMING JET LAG
There is no magic cure for jet lag except to reduce the severity of its effects. It is not true that pilots and cabin crew don’t get jet lag. It’s just that they have learnt to overcome its effects.
Some passengers take sleeping pills to get a little shut eye and also to mimic natural sleeping rhythms but this is not a cure for jet lag. Others believe that if they travel in first or business class comfort, they may escape jet lag. Of course the perks you get in first class make your flight more comfortable but do not do much for the body clock, which must go through a re-adjustment period in the new time zone.
There is a general rule that one must allow a day’s rest for every time zone crossed for the body clock to re-adjust. However, the rules for pilots are even more specific.
Pilots must be given sufficient rest in order to prevent jet lag from affecting their flying performance. There are flight regulations in place to prevent pilots from being overly tired when flying through many time zones. These regulations define when a pilot becomes acclimatised or un-acclimatised to a new destination.
Pilots are required to spend three nights at their destination when they fly across two time zones or more. For instance when a pilot is travelling to London (+0:00 GMT) from Kuala Lumpur (+8:00 GMT), which has a time zone difference of eight hours, he is required to spend three local nights in London to acclimatise. If he spends only 24 hours in London, he is still un-acclimatised and his subsequent flying duty will be reduced.
TRAVELLING COMFORTABLY
In a nutshell, it is advisable not to smoke, consume alcohol or take unnecessary medication while in flight. Sleep well before and during a long flight, consume small meals and drink plenty of fluids while flying.
Jet lag affects anyone who travels across many time zones. In a new destination, the body must re-adjust and adapt to the new time zone. The process of readjustment manifests itself as jet lag and understanding the reasons behind it would definitely make air travel more pleasant.
TIPS TO REDUCE JET LAG
- Synchronise your watch early by setting it to the local time of your destination, as soon as possible to help your mind adjust to that time zone. You can also adapt faster to the time diff erence by eating and sleeping according to the time at your destination. ›
- Drink plenty of water during your flight. In fact, this is a common tip for general air travel. Some doctors recommend drinking at least two litres of water right before departure. You get dehydrated quite easily in flight due to the dry cabin air. This results in diminished blood flow to your muscles and reduced kidney functions, all of which induce jet lag.
- ›You can also choose to take melatonin capsules (as directed by a doctor). Melatonin is a sleep-inducing hormone that is naturally produced in the pineal gland. ›
- Exercise and consume food at the appropriate time.
Captain Lim Khoy Hing is a former AirAsia Airbus A320 and AirAsia X A330/A340 pilot who also used to fly the Boeing 777. He has logged a total of more than 25,500 flying hours and is now a Simulator Flight Instructor with AirAsia X. In his spare time, he shares his opinion on aviation issues with others. For more air travel and aviation stories, check out his website, ‘Just About Flying’ at www.askcaptainlim.com.
Captain Lim’s first book, LIFE IN THE SKIES and its Mandarin version 【飞行日记】 are now available for purchase onboard all AirAsia and AirAsia X flights. Enjoy these great collections of articles from a veteran aviator.
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