How To Cope With Jet Lag
When travelers pass from one time zone to another, they suffer from
disrupted circadian rhythms, an uncomfortable feeling known as jet lag.
For instance, if you travel from California to New York, you "lose" 3
hours according to your body's clock. You will feel tired when the
alarm rings at 8 a.m. the next morning because, according to your
body's clock, it is still 5 a.m. It usually takes several days for your
body's cycles to adjust to the new time.
Disruption of circadian rhythms is involved in changes in sleep
patterns and can exacerbate the course of serious mood disorders, such
as bipolar disorder and depression. Other types of illnesses also are
affected by circadian rhythms; for example, heart attacks occur more
frequently in the morning while asthma attacks occur more often at
night.
To reduce the effects of jet lag, some doctors try to manipulate the
biological clock with a technique called light therapy. They expose
people to special lights, many times brighter than ordinary household
light, for several hours near the time the subjects want to wake up.
This helps them reset their biological clocks and adjust to a new time
zone.
Symptoms much like jet lag are common in people who work nights or
who perform shift work. Because these people's work schedules are at
odds with powerful sleep-regulating cues like sunlight, they often
become uncontrollably drowsy during work, and they may suffer insomnia
or other problems when they try to sleep. Shift workers have an
increased risk of heart problems, digestive disturbances, and emotional
and mental problems, all of which may be related to their sleeping
problems. The number and severity of workplace accidents also tend to
increase during the night shift. Major industrial accidents attributed
partly to errors made by fatigued night-shift workers include the Exxon
Valdez oil spill and the Three Mile Island and Chernobyl nuclear power
plant accidents. One study also found that medical interns working on
the night shift are twice as likely as others to misinterpret hospital
test records, which could endanger their patients. It may be possible
to reduce shift-related fatigue by using bright lig hts in the
workplace, minimizing shift changes, and taking scheduled naps.
Many people with total blindness experience life-long sleeping
problems because their retinas are unable to detect light. These people
have a kind of permanent jet lag and periodic insomnia because their
circadian rhythms follow their innate cycle rather than a 24-hour one.
Daily supplements of melatonin may improve night-time sleep for such
patients. However, since the high doses of melatonin found in most
supplements can build up in the body, long-term use of this substance
may create new problems. Because the potential side effects of
melatonin supplements are still largely unknown, most experts
discourage melatonin use by the general public.
Melatonin, a hormone of the pineal gland also produced by
extra-pineal tissues, acts as a biological response modifier; it is
postulated to act as a mediator of photic-induced anti-gonadotropic
activity in photoperiodic mammals (Budavari, 1989; Calbiochem, 1995).
Secretion is reported to increase during the night; and in humans it is
implicated in the regulation of sleep, mood, puberty, and ovarian
cycles. The synthetic counterpart, which is available as a prescription
and over-the-counter (OTC) drug/nutritional supplement as well as a
fine organic chemical, has been promoted as an anticancer,
radioprotective, contraceptive, antiobesity, antiaging and antifatigue
agent, and antidote to jet lag and degenerative diseases
(Garcia-Patterson et al., 1996). According to Olin (1996) melatonin is
an FDA approved "orphan drug" prescribed for the treatment of circadian
rhythm sleep disorders in blind patients.
You can't ask a fly to read, add, or operate heavy machinery," says
Dr. Michael Young of Rockefeller University. But you can rely on
Drosophila (fruit flies) to help fit all the pieces of the clock
together, he notes. Dr. Young and other scientists think that, in flies
and mammals, those pieces are a set of probably a dozen or so proteins.
It all started nearly 30 years ago, when scientists first stumbled
upon mutant fruit flies with a permanent case of jet lag. Since then,
NIGMS (National Institute of General Medical Sciences)-sponsored basic
research has fueled the fire for a recent explosion of discoveries in
the field of circadian rhythms.
So-called clock researchers now appreciate a striking evolutionary
parsimony in the molecules and pathways used by seemingly every
organism on the planet--including bacteria, fungi, plants, silk moths,
mice, and humans--to establish a 24-hour physiologic day. Many of the
protein parts of biological clocks in such widely diverse life forms
appear remarkably alike.
Such conservation of function has clock scientists excited that they
will be able to use fruit flies and other genetically tractable model
organisms to dissect the mammalian biological clock, a feat that would
lead to a better understanding of a host of human afflictions,
including not only jet lag but also a variety of sleep disorders and
mental illnesses.
In humans and other mammals, the body's "master clock" resides in a
small sliver of brain tissue called the suprachiasmatic nucleus, or
SCN. Light streaming into the eye of an animal sends a signal to the
SCN, where 10,000 individual cellular pacemakers are housed. Within
each of these SCN neurons, levels of a cast of protein characters--with
names such as Period, Timeless, and Clock--rise and fall throughout the
course of the day. Each protein helps keep cellular time by acting in a
feedback loop in which the other proteins' production is shut off
during certain parts of the day.
See also: Insomnia
When travelers pass from one time zone to another, they suffer from
disrupted circadian rhythms, an uncomfortable feeling known as jet lag.
For instance, if you travel from California to New York, you "lose" 3
hours according to your body's clock. You will feel tired when the
alarm rings at 8 a.m. the next morning because, according to your
body's clock, it is still 5 a.m. It usually takes several days for your
body's cycles to adjust to the new time.
Disruption of circadian rhythms is involved in changes in sleep
patterns and can exacerbate the course of serious mood disorders, such
as bipolar disorder and depression. Other types of illnesses also are
affected by circadian rhythms; for example, heart attacks occur more
frequently in the morning while asthma attacks occur more often at
night.
To reduce the effects of jet lag, some doctors try to manipulate the
biological clock with a technique called light therapy. They expose
people to special lights, many times brighter than ordinary household
light, for several hours near the time the subjects want to wake up.
This helps them reset their biological clocks and adjust to a new time
zone.
Symptoms much like jet lag are common in people who work nights or
who perform shift work. Because these people's work schedules are at
odds with powerful sleep-regulating cues like sunlight, they often
become uncontrollably drowsy during work, and they may suffer insomnia
or other problems when they try to sleep. Shift workers have an
increased risk of heart problems, digestive disturbances, and emotional
and mental problems, all of which may be related to their sleeping
problems. The number and severity of workplace accidents also tend to
increase during the night shift. Major industrial accidents attributed
partly to errors made by fatigued night-shift workers include the Exxon
Valdez oil spill and the Three Mile Island and Chernobyl nuclear power
plant accidents. One study also found that medical interns working on
the night shift are twice as likely as others to misinterpret hospital
test records, which could endanger their patients. It may be possible
to reduce shift-related fatigue by using bright lig hts in the
workplace, minimizing shift changes, and taking scheduled naps.
Many people with total blindness experience life-long sleeping
problems because their retinas are unable to detect light. These people
have a kind of permanent jet lag and periodic insomnia because their
circadian rhythms follow their innate cycle rather than a 24-hour one.
Daily supplements of melatonin may improve night-time sleep for such
patients. However, since the high doses of melatonin found in most
supplements can build up in the body, long-term use of this substance
may create new problems. Because the potential side effects of
melatonin supplements are still largely unknown, most experts
discourage melatonin use by the general public.
Melatonin, a hormone of the pineal gland also produced by
extra-pineal tissues, acts as a biological response modifier; it is
postulated to act as a mediator of photic-induced anti-gonadotropic
activity in photoperiodic mammals (Budavari, 1989; Calbiochem, 1995).
Secretion is reported to increase during the night; and in humans it is
implicated in the regulation of sleep, mood, puberty, and ovarian
cycles. The synthetic counterpart, which is available as a prescription
and over-the-counter (OTC) drug/nutritional supplement as well as a
fine organic chemical, has been promoted as an anticancer,
radioprotective, contraceptive, antiobesity, antiaging and antifatigue
agent, and antidote to jet lag and degenerative diseases
(Garcia-Patterson et al., 1996). According to Olin (1996) melatonin is
an FDA approved "orphan drug" prescribed for the treatment of circadian
rhythm sleep disorders in blind patients.
You can't ask a fly to read, add, or operate heavy machinery," says
Dr. Michael Young of Rockefeller University. But you can rely on
Drosophila (fruit flies) to help fit all the pieces of the clock
together, he notes. Dr. Young and other scientists think that, in flies
and mammals, those pieces are a set of probably a dozen or so proteins.
It all started nearly 30 years ago, when scientists first stumbled
upon mutant fruit flies with a permanent case of jet lag. Since then,
NIGMS (National Institute of General Medical Sciences)-sponsored basic
research has fueled the fire for a recent explosion of discoveries in
the field of circadian rhythms.
So-called clock researchers now appreciate a striking evolutionary
parsimony in the molecules and pathways used by seemingly every
organism on the planet--including bacteria, fungi, plants, silk moths,
mice, and humans--to establish a 24-hour physiologic day. Many of the
protein parts of biological clocks in such widely diverse life forms
appear remarkably alike.
Such conservation of function has clock scientists excited that they
will be able to use fruit flies and other genetically tractable model
organisms to dissect the mammalian biological clock, a feat that would
lead to a better understanding of a host of human afflictions,
including not only jet lag but also a variety of sleep disorders and
mental illnesses.
In humans and other mammals, the body's "master clock" resides in a
small sliver of brain tissue called the suprachiasmatic nucleus, or
SCN. Light streaming into the eye of an animal sends a signal to the
SCN, where 10,000 individual cellular pacemakers are housed. Within
each of these SCN neurons, levels of a cast of protein characters--with
names such as Period, Timeless, and Clock--rise and fall throughout the
course of the day. Each protein helps keep cellular time by acting in a
feedback loop in which the other proteins' production is shut off
during certain parts of the day.
See also: Insomnia
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