Unusual sleepers helped by melatonin

Researchers have found that melatonin is the most affective antidote for sleeplessness when used for sleep at non-regular hours.

Brigham and Women’s Hospital and Harvard Medical School researchers conducted a double-blind placebo-controlled clinical study using melatonin during non-typical sleep times.
 
They found that orally taken melatonin during abnormal sleep times significantly improved an individual’s ability to sleep.
 
The findings are expected to be particularly important for night-shift or rotating workers, travellers suffering jet lag and individuals with advanced or delayed sleep phase syndrome.
 
Melatonin is a hormone that is naturally-produced by the body at night.
 
The hormone helps the brain determine when it is day and night, which promotes regular sleep cycles and circadian timing.
 
Retinal light exposure inhibits the release of melatonin.
 
The trial used thirty-six participants (21 men and 15 women), between the ages of 18 and 30 with no significant past or current medical, sleep or psychological disorders.
 
All participants abstained from alcohol, caffeine, nicotine, illicit substances and prescription and non-prescription medications for three weeks prior to commencement of the study.
 
Partakers were studied in sound-proof suites that were free of ‘time-clues’, and were examined for three days and nights in the lab on conventional sleep schedules to measure their normal sleep structure and melatonin production.
 
“Participants were then kept on a 20-hour sleep-wake schedule, simulating a traveller crossing four time zones eastward every day,” explained Dr Charles Czeisler, Chief of the Division of Sleep Medicine at Brigham and Women’s Hospital and senior author of the study.
 
“For the next three weeks, thirty minutes before each sleep episode, participants ingested either a placebo, 0.3milligrams (mg), or 5.0mg of pharmaceutical grade melatonin.”
 
The results of the study detailed sleep efficiency over six-hour and 40-minute episodes and was found to be significantly higher in groups that took melatonin during times when the body was not naturally producing the hormone.
 
During those times, participants taking 5.0mg of melatonin had a sleep efficiency of 83 per cent and persons taking 0.3mg melatonin had a sleep efficiency of 84 per cent.
 
Sleep efficiency in both of these groups was significantly greater than that in participants taking placebo, who had a sleep efficiency of 77 per cent.
 
There was no significant difference in sleep efficiency among all participants during times when melatonin was being produced in the body.
 
Czeisler concluded: “Melatonin enabled these participants to obtain an extra half hour of sleep when they attempted to do so during the day, at a time when they were not producing melatonin themselves. 
 
“Melatonin did not help these young adults sleep at night, when their body was already producing melatonin.” 
 
Co-author Derk-Jan Dijk, Director of the Surrey Sleep Research Centre, added: “These data leave little doubt about the effectiveness of melatonin in alleviating sleep disturbances when attempting to sleep at the wrong time of day, at least under laboratory conditions.”
 
The findings appear in the 1 May 2006 issue of the journal Sleep.

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