Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, October 3, 1995 TAG: 9510030049
SECTION: EXTRA PAGE: 1 EDITION: METRO
SOURCE: JANE BRODY
DATELINE: LENGTH: Medium
Research interest in melatonin began with the discoveries that light suppresses its secretion and that the hormone has a strong influence on a person's circadian rhythm, as scientists call the body clock, which influences when people are likely to fall asleep or wake up, among dozens of other internal rhythms.
Perhaps, scientists reasoned, just as light can shift the clock, melatonin might be used to help reset a clock that is out of sync with a person's surroundings.
This loss of synchronization can happen when people fly across time zones or when workers shift from working days to nights, then back to days. In addition, some people suffer from a sleep disorder resembling permanent jet lag; their body clocks keep them awake at bedtime and asleep in the morning when they are supposed to get up and start their day.
Distortions in the body clock are also a factor in winter depression, the condition called seasonally activated depressive disorder, or SADD. Winter depression is typically associated with a body clock that behaves as if it were earlier than the actual time; as a result, those suffering from winter depression often have trouble waking up in the morning during the months when dawn breaks late and dusk falls early.
Melatonin is a hormone produced by the light-sensitive pineal gland at the base of the brain. Melatonin is secreted only during darkness. Its secretion stops when the eyes are exposed to daylight or its artificial equivalent, an exposure that can occur even when the eyes are closed.
The trick in properly using melatonin to reset the body clock, a step called phase shifting, is to take the hormone at the right time and in the right amount to adjust the clock without causing sleepiness at the wrong time. Unfortunately, both the melatonin dosages commonly sold and the instructions on how to use the hormone are inappropriate for adjusting a person's circadian rhythm.
Dr. Alfred Lewy, an expert on circadian rhythms at the Oregon Health Sciences University in Portland, said that it takes only tiny amounts of melatonin, much less than a milligram, to reset the body clock.
The higher doses, from two milligrams to tens of milligrams, that are now widely sold over the counter will reset the clock, but usually cause sleepiness, which is not what most people want upon arriving in Paris in the morning or when starting a night shift.
Furthermore, all products now marketed tell users to take melatonin only at night shortly before bedtime. But this advice, which is meant to keep people from falling asleep during the day, possibly while driving or operating hazardous machinery, is of no help to people who are trying to avoid jet lag.
To counter jet lag, the goal is to take a small amount of melatonin for several days at a time that will either advance the body clock or delay it, depending upon the direction of travel.
For example, when traveling from coast to coast in the United States, a three-hour shift in the clock is needed. If you travel from the West Coast to the East Coast, where it is three hours later, you want your body clock to advance by three hours so that you will feel tired on East Coast time.
Lewy said that when going from Pacific to Eastern time, melatonin should be taken about 2 p.m. the day before a person travels, the same time on the day of travel and at 5 p.m. on the first full day on the East Coast (which would 2 p.m. Pacific time).
This will advance the body clock and make it easier to fall asleep at bedtime in the East and to wake up at a reasonable hour the next morning. Upon returning to Pacific time, however, melatonin should be taken on all three days when you wake up in the morning. This will delay the body clock, which will help keep a person awake until bedtime and asleep until morning in the West.
by CNB