Tuesday, April 10, 2007

Tired of jet lag - Jet lag is more severe where you cross several time zones

I RECENTLY went to the US for the first time, and found it very difficult to sleep. I would wake up at 2am and feel sleepy about 7pm. My friends said I was experiencing jet lag. l'd always thought jet lag was a sort of tiredness you get from sitting still in a plane for too long and being unable to sleep properly.

Jet lag is now known as one of the 84 known or suspected sleep disorders. It is also known as desynchronosis.

It happens when your biological or internal clock is out of sync with the local time. This occurs when you are travelling
to a new time zone or more specifically, crossing the earth's meridians.

In general, jet lag is more severe when:

  • You cross several time zones. You are more likely to experience severe jet lag when you cross over to the other side of the world.
  • You fly east rather than west. That's why you are more likely to take longer to recover from jet lag when you return from Europe to Malaysia than flying from Malaysia to Europe.
  • When you fly east, you will have difficult , trying to get to sleep, because the time zone there is several hours ahead of you. Luckily for us in Malaysia, not many countries we typically fly to are many hours ahead of us. When you fly west (Europe, Middle East), you tend to feel very sleepy early on and wake early. This is because they are several hours behind US.

Some people are more susceptible to jet lag than others, usually those with increasing age. If you have a pre-existing
sleep disorder, your jet lag tends to be more severe. Jet lag can last for several days as your body remains in its original
biological clock. But when your body tries to adjust its circadian rhythm to the new time zone, symptoms result.

What is my body's circadian rhythm? Do I have a rhythm?

Your circadian rhythm (circa = about, dian = day) reflects changes in your bodily function that occur within a 24-hour period. This includes maintenance of body temperature, airway function, glandular and hormonal function and kidney maintenance.

Have you ever noticed that your body temperature rises throughout the day, drops around midnight and begins to rise again before 6am? This is the same with mental alertness and ability to fall asleep. These rhythms donot occur with light or dark. Even in full Antarctic winter, when it is fu||y dark people continue to wake up and sleep according to their 24-hour circadian cycles.

You are most likely to fall asleep during 3am to 5am and 3pm to 5pm. That's why you feel sleepy in the afternoon, especially after eating lunch. This natural sleepiness is not necessarily associated with having a heavy lunch.

To maximise daylight, the human body has long synchronised itself to be awake during the day and to sleep at night. This is regulated through the eyes, in particular, the retina, which feeds through a nerve network in the hypothalamus, the chief regulator of circadian rhythms.

Is difficulty in falling asleep or sleeping too early the only symptoms of jet lag? What about mood alteration?

There are many symptoms associated with jet lag other than sleep alterations. Some people feel bone tired.

In the next moment, they can feel elated and excited.

You can also have stomachaches and headaches. You can become irritable, have decreased awareness and decreased con-centration. Some symptoms you might experience are related more to the dry environment of long haul flights, like dry eyes, irritated sinuses, earaches, muscle cramps and bloating.

Most travellers return to their normal sleep-wake pattern after a day or two, although in some, this may persist for a week.

What can ! do for jet lag? Will taking sleeping pills during the flight help?

Sleeping pills may help some, especially those short acting ones, but are not always the answer for many, especially since they can have a lot of side effects that can impair your enjoyment of your trip once you get there/or home. Always consult a
doctor before you take a sleep aid of any sort.

There is actually no specific treatment for jet lag. However, here are some helpful

  • Get a good night's sleep the night before you take your plane. Avoid alcohol, caffeine or cigarettes.
  • Some people psychologically help themselves to adjust by resetting their watches to the new time zone as soon as they depart inside the plane itself. (The airlines certainly help you do that, serving meals as according to that particular time zone you are crossing, and not according
  • to the time of your departure area.)
  • Take a daytime flight if you are flying east (for example, from London to Malaysia). Then you can arrive almost at home time, or in the afternoon.
  • Try to sleep at the normal time for that country When you arrive in your new time zone.

What about melatonin?

Melatonin is a hormone that is synthesised naturally by the pineal gland and is inhibited when your eye retina is exposed to light. Some people think it helps influence your circadian rhythm i.e advancing your biological clock so you need less sleep. Some people with jet lag benefit from it and some don't. More studies need to be done on it before it can be truly recommended for jet lag.

* Dr YLM graduated as a medical doctor, and has been writing for many years on various subjects such as medicine, health advice, computers and entertainment. The information contained in this column is for general educational purposes only. Neither The Star nor the author gives any warranty on accuracy, completeness, functionality, usefulness or other assurances as to such information. The Star and the author disclaim all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.



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