NEW YORK, Sep 02 (Reuters Health) -- Melatonin, a hormone widely purported to stave off jet lag, may not offer much help to weary travelers, according to a new study of Norwegian doctors.
"The use of melatonin for preventing jet lag needs further study," according to a report in the September issue of the American Journal of Psychiatry.
In the new study, 257 Norwegian physicians who visited New York for five days received either 5 milligrams (mg) at bedtime, 0.5 mg at bedtime, 0.5 mg taken at various times each day, or dummy pills to be taken on the first day of travel and continued for five days. Participants rated their jet lag symptoms on the day they traveled from New York to Oslo, Norway, or 6 hours eastward, and for the ensuing six days in Norway. Results were compared to baseline measurement of jet lag taken when the doctors visited New York.
"Despite earlier studies that show positive effects from taking melatonin, our study showed that the different doses of melatonin were no better than placebo at preventing jet lag symptoms," lead study author Dr. Robert L. Spitzer, a psychiatrist at Columbia University in New York, told Reuters Health.
"The take-home message is that one should be cautious about concluding that melatonin necessary helps jet lag," he adds. "I personally have stopped taking it when traveling."
Although melatonin was not found to be effective in the new study, Spitzer and colleagues call for more study because perhaps melatonin may benefit a more diverse group of participants or those who make lengthier journeys
Jet lag typically refers to daytime sleepiness, fatigue, impaired alertness and other symptoms that afflict individuals for several days after air travel, Spitzer and colleagues note.
It is believed to be caused by failure of the body's internal clock to adjust to a change in time zones. Sold as a supplement, melatonin is released into the bloodstream by the pineal gland according to a daily cycle set by the body's internal clock. Jet lag may be caused by disruption to the body's internal clock or circadian rhythms.
In the study, about 63% of all participants reported at least moderate jet lag on their first day back in Norway, followed by improvements in the ensuing five days. The most commonly reported symptoms were fatigue, daytime sleepiness, decreased daytime alertness and trouble concentrating or thinking clearly, researchers report.
About one-third reported no jet lag at all or only a little bit, the study showed "Many people don't suffer from jet lag at all, it's very variable and can be extremely short-lived," Spitzer notes.
