Air travelers pay twice for the pleasure of flying to exotic, distant places. There's the ticket to buy, of course, and then there's the biological tab.
"Jet lag is the price we pay for being able to travel the way we do now," says Lynne Lamberg, author of "Bodyrhythms, Chronobiology and Peak Performance" (William Morrow and Co., (Chronobiology is the study of body time.) But the price may be coming down if major studies confirm what a few small ones have called to light about what has been dubbed "the darkness hormone."
That hormone, melatonin, was the talk of last weekend's annual meeting of the Association of Professional Sleep Societies in Nashville, Tenn., says Ms. Lamberg. She had just returned to her Baltimore home from the conference, where she spoke on the biological effects of shift work. (She has written three other books on sleep and dreams, including one for the American Medical Association.)
The upset to the body's 200 or so internal clocks when working nights is akin to that of jet lag, she says. The body's time clocks were "set" by the thousands of years humans worked during daylight hours and slept while it was dark. Modern life with its odd work hours, conveniences and pleasures can throw those internal rhythms out of whack.
Melatonin, secreted by the pineal gland in the center of the brain, may be a key to more quickly resetting disturbed time clocks.
The hormone is secreted in the darkness," Ms. Lamberg says. "It starts about 9 o'clock and is secreted through the night -- unless a person is in a bright, lighted environment. Bright light, equal to the intensity of daylight, suppresses it. It's kind of like light central. It tells the brain what time it is by the length of the day and signals various other organs in the body about the length of the day."
The day's duration -- light -- affects both what our bodies expect to do at certain times and mental and physiological states, everything from depression and joy to when we urinate or have sex. If the day is lengthened or shortened -- as in traveling west or east -- the clocks get confused.
The theory is that synthetic melatonin could help the body reset its change-resistant clocks faster after they've been thrown off by working when the body thinks it should be sleeping or by crossing quickly through time zones. It might help the body adapt to different environmental time cues (such as daylight and mealtimes) more quickly.
"Scientists are being very cautious about it," Ms. Lamberg says. "So far, all scientists know is that there's a correlation, but it's not proven that it's a causation."
Because it's not a regulated substance, health-food stores carry melatonin for those who would try it as a jet lag preventive. Ms. Lamberg asked several doctors at the conference if they would take it or recommend it. They were, once again, cautious.
Ms. Lamberg offers a complete list in her book of techniques for helping the body adapt as quickly as possible when visiting distant shores for more than three or four days. Here are a few of those guidelines.
* Before departing: Go to bed and rise earlier if heading east, and later if heading west. Slightly shift mealtimes and daily routines toward your destination's time schedule, and begin the trip well rested. Sleep loss exacerbates other jet-lag symptoms.
* En route: Set your watch to destination time as a psychological step toward "doing what the Romans do." If it's nighttime at your destination, try to sleep on the plane. If daytime, avoid sleeping. Drink water and fruit juices -- no alcohol, carbonated or caffeinated drinks.
* After arriving: Expect a certain degree of jet lag and make allowances for lowered performance. When traveling east, schedule important activities in the afternoon; when traveling west, schedule them in the morning. Spend as many daylight hours outdoors as possible when you first arrive. (Travelers who spend time outdoors adapt twice as fast as those who do not.) Eat lightly and on local time, even when you're not hungry. And try to get at least four hours of sleep during your usual time period at home until you've adjusted. If feeling sleep deprived, take a short nap in the afternoon.