combating jet lag
Crossing time zones
This confuses the body clock because it has to adjust to a new time and new patterns of light and activity. To make matters worse, not all internal body functions adjust at the same rate. So your sleep/wake cycle may adjust more quickly than your temperature. Your digestion may be on yet another schedule. Confusing the clock like this causes the mental and physical upset we call jet lag.
Go west
Though the body clock has difficulty adjusting to time zone travel, it prefers flying in an east to west direction. This is because although we live on a 24 hour day, the natural rhythm of our clock is programmed to operate on a day that is longer than 24 hours. So our internal clock can naturally extend our day but it finds it very difficult to reduce the hours in our day.
When flying west you are adding hours and going in the natural direction of your internal clock. For example, flying westward from London to New York involves extending your day by five hours, while the eastward flight from New York to London results in shrinking your day by five hours.
Managing jet lag
Because it can take the body clock anything from several days to several weeks to fully adjust to a new time zone, it may be less disruptive to keep yourself on your home time schedule if you are only going to be away from home for a short time (about 48 hours or less).
If your trip is going to be longer, you should start to adjust to your new time zone as soon as you board the plane.
How to keep your body clock on home time
You need to do a bit of advance planning, but these steps will help:
1. Calculate the time difference between your home time and the time at your destination
2. Consider when you normally would be asleep and awake on your home time compared to the times at the new destination
3. Make a note of the destination times that correspond with times when your body clock would be at maximum sleepiness at home (3-5am and on a lesser level 3-5pm)
4. Try to avoid important business meetings scheduled at these times of maximum sleepiness at home
5. Try not to be in the light at your destination if you would normally be in darkness at home. You can do this by staying indoors or wearing sunglasses when you go out
6. When planning meals try to keep your stomach on home time. So if it is dinner time at your destination, but breakfast on your home time, try to have something light, rather than a full heavy dinner that your stomach may not be ready to digest
from british airways