Times Zones and Jet Lag

The effects of world time zones and distance travel

The following article is a guide for crew members who are working a flight or travelling on vacation on how to best handle Jetlag.

What is Jetlag?

Jet lag, also called desynchronosis, is a temporary disorder that causes fatigue, insomnia, and other symptoms as a result of air travel across time zones.

 

What are other symptoms of jet lag?

Besides fatigue and insomnia, a jet lag sufferer may experience anxiety, constipation, diarrhoea, confusion, dehydration, headache, irritability, nausea, sweating, coordination problems, and even memory loss. Some individuals report additional symptoms, such as heartbeat irregularities and increased susceptibility to illness.

 

What is a time zone?

A time zone is a geographical region which has the same time everywhere within it. The world has 24 time zones, one for each hour in the day. Each zone runs from north to south in strips that are approximately 1,000 miles (1,600 kilometres) wide. (The actual width of each zone varies to accommodate political and geographical boundaries.) As the earth rotates, dawn occurs at a set hour in one time zone, then an hour later in the time zone immediately to the west and so on through the 24-hour cycle. Thus, in the U.S., when it is 6 a.m. in the Eastern Time Zone, it is 5 a.m. in the Central Zone, 4 a.m. in the Mountain Zone, and 3 a.m. in the Pacific Zone.

Why does jet lag occur?

The cause of jet lag is the inability of the body of a traveller to immediately adjust to the time in a different zone. Thus, when a New Yorker arrives in Paris at midnight Paris time, his or her body continues to operate on New York time. As the body struggles to cope with the new schedule, temporary insomnia, fatigue, irritability, and an impaired ability to concentrate may set in. The changed bathroom schedule may cause constipation or diarrhoea, and the brain may become confused and disoriented as it attempts to juggle schedules.

How does the body keep time?

A tiny part of the brain called the hypothalamus acts like an alarm clock to activate various body functions such as hunger, thirst, and sleep. It also regulates body temperature, blood pressure, and the level of hormones and glucose in the bloodstream. To help the body tell the time of day, fibres in the optic nerve of the eye transmit perceptions of light and darkness to a timekeeping centre within the hypothalamus. Thus, when the eye of an air traveller perceives dawn or dusk many hours earlier or later than usual, the hypothalamus may trigger activities that the rest of the body is not ready for, and jet lag occurs.

Does the direction of travel matter?

Yes. Travellers flying north or south in the same time zone typically experience the fewest problems because the time of day always remains the same as in the place where the flight originated. These travellers may experience discomfort, but this usually results from confinement in an airplane for a long time or from differences in climate, culture, and diet at the destination location. Time does not play a role.

Travellers flying east, on the other hand, typically experience the most problems because they "lose" time. For example, on an international flight from Washington, D.C., to Mecca, Saudi Arabia, a traveller loses eight hours. Meals, sleep, bowel habits, and other daily routines are all pushed ahead eight hours.

Travellers flying west "gain" time and usually have an easier time adjusting than eastward travellers. However, they too experience symptoms of jet lag after landing because they still must adjust to a different schedule.

Do the symptoms of jet lag vary in intensity?

Yes. People flying across only one or two time zones may be able to adjust without noticeable effects of the time change. Those flying across three or more time zones will likely develop noticeable symptoms of jet lag. Generally, the intensity of symptoms varies in relation to the number of time zones crossed and the direction of travel.

What are the best ways to cope with jet lag?

Tip 1: Stay in shape

If you are in good physical condition, stay that way. In other words, long before you embark, continue to exercise, eat right, and get plenty of rest. Your physical stamina and conditioning will enable you to cope better after you land. If you are not physically fit, or have a poor diet, begin shaping up and eating right several weeks before your trip.

Tip 2: Get medical advice

If you are not feeling well, consult your physician well in advance of your departure to plan a strategy.

Tip 3: Change your schedule

If your stay in the destination time zone will last more than a few days, begin adjusting your body to the new time zone before you leave. For example, if you are traveling from the U.S. to Europe for a one-month vacation, set your daily routine back an hour or more three to four weeks before departure. Then, set it back another hour the following week and the week after that. Easing into the new schedule gradually in familiar surroundings will save your body the shock of adjusting all at once.

Tip 4: Avoid alcohol

Crew members are not permitted alcohol intake while on duty. When travelling on vacation, do not drink alcoholic beverages the day before your flight, during your flight, or the day after your flight. These beverages can cause dehydration, disrupt sleeping schedules, and trigger nausea and general discomfort.

Tip 5: Avoid caffeine

Likewise, do not drink caffeinated beverages before, during, or just after the flight. Caffeine can also cause dehydration and disrupt sleeping schedules. What's more, caffeine can jangle your nerves and intensify any travel anxiety you may already be feeling.

Tip 6: Drink water

Drink plenty of water, especially during the flight, to counteract the effects of the dry atmosphere inside the plane. Consider taking your own water aboard the airplane if allowed.

Tip 7: Move around on the plane

When working a flight as a crew member, you will be moving around the aircraft throughout most of the flight. When travelling as a passenger, exercise your legs from time to time. Move them up and down and back and forth. Bend your knees. Stand up and sit down. Every hour or two, get up and walk around. Do not take sleeping pills, and do not nap for more than an hour at a time.

These measures have a twofold purpose. First, they reduce your risk of developing a blood clot in the legs. Research shows that long periods of sitting can slow blood movement in and to the legs, thereby increasing the risk of a clot. The seat is partly to blame. It presses against the veins in the leg, restricting blood flow. Inactivity also plays a role. It decelerates the movement of blood through veins.

If a clot forms, it sometimes breaks loose and travels to the lungs, lodges in an artery, and inhibits blood flow. The victim may experience pain and breathing problems and cough up blood. If the clot is large, the victim could die. Second, remaining active, even in a small way, revitalizes and refreshes your body, wards off stiffness, and promotes mental and physical acuity which can ease the symptoms of jet lag.

Tip 8: Break up your trip

When travelling as a passenger, and time permits, on long flights travelling across eight, 10, or even 12 time zones, break up your trip, if feasible, with a stay in a city about halfway to your destination. For example, if you are travelling from New York to Bombay, India, schedule a stopover of a few days in Dublin or Paris. (At noon in New York, it is 5 p.m. in Dublin, 6 p.m. in Paris, and 10:30 p.m. in Bombay.)

Tip 9: Wear comfortable shoes and clothes

When travelling as a passenger on a long trip, how you feel is more important than how you look. So, wear comfortable clothes and shoes. Avoid items that pinch, restrict, or chafe. When selecting your trip outfit, keep in mind the climate in your destination time zone. Dress for your destination.

Tip 10: Adapt to the local schedule

The sooner you adapt to the local schedule, the quicker your body will adjust. Therefore, if you arrive at noon local time (but 6 a.m. your time), eat lunch, not breakfast. During the day, expose your body to sunlight by taking walks or sitting in outdoor cafes. The sunlight will cue your hypothalamus to reduce the production of sleep-inducing melatonin during the day, thereby initiating the process of resetting your internal clock.

Tip 12: Sleeping wisely

Try to establish sleeping patterns without resorting to pills. However, if you have difficulty sleeping on the first two or three nights, it is okay to take a natural sedative.

Happy flying!