Last Updated Apr 6, 2011 8:18 AM EDT
Jet lag occurs when your circadian clock gets out of sync with the time zone you're travelling to and your new sleep/wake cycle, explains Charmane Eastman, Ph.D. director of the biological rhythms research lab at Rush. When your natural "home zone" rhythm is shutting down for the day, the new time zone is having you eat, talk, negotiate and make business decisions. The fatigue you feel is not just due to loss of sleep, which can be pretty much made up the next night. As long as your circadian rhythm is out of sync, Jet lag can linger for days and you're more likely to be exhausted when you get home.
Here's how it works. To retrain your body clock, you have to advance the time your body hits its lowest low--when your body temperature drops to its lowest and you feel the sleepiest. Going East, say from Chicago to Paris, is harder for us to adjust to, so I'll focus on that.
If you follow these five steps, your body clock will advance about one hour per day, so that after a few days, your sleepiest time will occur while you're asleep, not in the middle of the day. To demonstrate, I'm using the Chicago to Paris flight, a seven-hour difference in zones and you can try to follow along on this chart:
- Know your temperature nadir. Take the time you'd naturally wake up, say, if you didn't have to get up for work, and count back three hours. Jot down what time that is in the zone you're traveling to. Say your nadir is 5 am. If you take the Chicago to Paris example, 5 am Chicago time is noon in Paris.
- Avoid light before your body temp nadir. When you arrive in Paris, avoid light exposure before your temperature nadir Paris time, or in this example, noon. Stay indoors or buy dark sunglasses like these Uvex blue blockers. They may not be the hippest but they work. If you don't avoid light, it actually worsens the jet lag, by shifting your body clock in the wrong direction, says Eastman.
- Now get light. After you pass your nadir in the time zone you're traveling to, you should then expose yourself to light for the rest of the afternoon. In this example, you'd go outdoors after noon.
- Take melatonin. Melatonin does two things, it resets your clock and makes you sleepy. On your first three evenings, take 3 mg of melatonin, available over-the-counter, before bedtime. On day 4, take 5 mg of melatonin before bed, and on day 5 and 6, take 5 mg but an hour earlier each night (progressively).
- Avoid light in the mornings. On day 2 wear your dark glasses until 11 (an hour earlier than your natural nadir), and on day three wear them until 10 (two hours earlier). Then toss them in yours suitcase.
Have you found other ways to prevent jet lag?
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