Jet lag, resulting from long distance airplane travel, impedes physical and mental performance because of disruption of the internal body clock and irregular exposure to light. Common jet lag symptoms include fatigue; insomnia; swelling limbs; ear, nose and eye irritations; headaches; indigestion; lightheadedness; and anxiety. 

  As many as 94 percent of long-haul fliers experience some form of jet lag, which occurs because changes in time zones confuse the body's 24-hour inner clock, known as circadian rhythms. When traveling to a different time zone, the circadian clock needs time to adjust. 

  Crossing time zones can cause you to wake during the night and fall asleep during the day. Your built-in circadian rhythms have been disturbed, and it takes about one day for the body to adapt for each time zone crossed. In other words, five hours time difference will require approximately five days adaptation. 

  A melatonin supplement may be used to help alleviate the effects of jet lag, said Dr. Robert Schriner, medical director of the Baptist Sleep Disorders Center at Baptist-Collierville. Taking melatonin at bedtime three days prior to departure and at bedtime for three days after arrival is recommended. 

  Melatonin is a natural hormone made by your body's pineal gland, which lies at the base of the brain. Its secretion is stimulated by the dark and inhibited by light. As natural melatonin production rises, you begin to feel less alert, your body temperature starts to fall and sleep seems more inviting. Natural melatonin levels drop quickly with the dawning of a new day, but melatonin supplements can help induce sleep at irregular times, which helps the circadian rhythms adjust more quickly. 

  Melatonin is sold over-the-counter in health food shops, but Schriner advises travelers check with their doctor before taking any kind of medication, such as melatonin or any other sleeping agent. 

  If melatonin is not right for you, there are other ways of adapting to new time zones. 

  Use the power of light to reset your body clock by exposing yourself to bright light in the mornings and minimizing exposure of light in the evenings upon arrival, Schriner says. Also, before you travel, for each time zone you'll cross, try waking and going to sleep an hour later if you are traveling west and an hour earlier if you are traveling east.

  Another useful tip is to sleep on the airplane if you will arrive in the morning, or go right to sleep when you get to the hotel if it is nighttime at your destination. 

  While on the airplane, reading a relaxing book, drinking plenty of water, wearing an eye mask or using a neck pillow, blanket and earplugs may help you fall asleep.

  At the hotel, limiting caffeine, alcohol and tobacco use; requesting a room away from noisy areas; and using the television or fan to create background noise may improve your quality of sleep. 
Treatment for sleep disorders

  Sleep Disorders Centers treat a variety of sleep-related problems, including:

• Obstructive Sleep Apnea, a nighttime breathing disorder, is the most common problem seen in the center. Signs of this disorder include loud snoring, abnormal breathing and excessive daytime fatigue/sleepiness. Lung problems, heart problems and stroke may complicate this disorder. 
• Narcolepsy, a disorder of excessive daytime sleepiness, is characterized by sudden and uncontrollable attacks of sleep.
• Insomnia, difficulty going to sleep or maintaining sleep, requires specific diagnosis of the type of insomnia for the best treatment. 
• Restless Legs Syndrome and Periodic Limb Movement Disorder, repetitive movement problems that interrupt sleep, may be present in cases of insomnia.