The hormone melatonin, in conjunction with exercise and exposure to light, may help the body resynchronize sleep patterns after traveling across several time zones, according to a new study in the Journal of Pineal Research (2002;32:41-6). Melatonin, a hormone manufactured in the brain that promotes sleep, is produced in high amounts during periods of darkness. Research suggests that taking supplemental melatonin may help travelers get back to a regular sleep pattern more quickly than waiting for the body to regulate the sleep cycle on its own.
Researchers investigated the effects of 3 mg per night of supplemental melatonin on 22 professional soccer players and coaches traveling across twelve time zones. All participants engaged in moderate exercise outdoors twice a day for a total of six hours. The athletes recovered from their jet lag after approximately two days, whereas the expected time of recovery after traveling across 12 time zones is about six days. These results show that melatonin, exercise, and light exposure significantly decrease the time required to return to normal sleep patterns.
While this study examines the effect of melatonin on people traveling halfway around the world, other studies have shown that melatonin has the same beneficial effect when shorter distances were traveled. The optimal intake amount of melatonin ranges from 0.5 mg to 3 mg and is best taken 30 minutes before bedtime.
In addition to treating jet lag, melatonin may also help those suffering from insomnia and swing shift workers whose sleeping time changes from week to week. Although there is little research to support using melatonin for swing shift workers, given its safety record it would be reasonable to try.
Although melatonin is generally safe, too much may produce side effects, especially a feeling of being overtired or groggy. Because of this potential side effect, it is recommended not to drive or operate machinery for several hours after taking melatonin. In addition, the long-term safety of melatonin has not been adequately studied; therefore, one should consult a physician before beginning treatment with melatonin to determine whether it is appropriate and in what amounts.